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Trying to identify these LEGO pieces
Does anyone know what set(s) these belong to? I have been searching but have had no luck. Thank you.

Both the top build and the bottom left build are not LEGO, but from a clone manufacturer.

Really? I just checked and the bricks and they do not say lego on the dots. Thank you very much for pointing that out to me. I was very confused as to why I couldn't identify the set. Lego 101.

The back part of this set is from set 7693 ETX Alien Strike from the Mars Mission theme from 2007. I found this by looking for sets that had at least 4 of the “Plate 1x2 with bar - free ends” in Orange, and then looked at all the matching sets to find the “flag” piece with the (in your case) badly placed sticker.

The front slope with the circled 4 is not from that set; in fact, I cannot find any such piece on BrickLink at all, so this might be from a clone set as were the other items you originally posted in your question but since removed. Does it have LEGO markings anywhere on the piece?

Thank you again. I found a box of broken legos when clearing the attic. This was built like this so I just assumed that it fell off as is. I took it apart now and the "4" does not have lego on the dots.  I know my nephew had purchased a bag of pieces at a flea market years ago. He may have built this, and now I figured it was a broken set. Thank you for your time!


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Size of packaging of Battery Box 88015
I am interested in the dimensions of the packaging of this product. I am able to find only the dimensions of the battery box itself, but not the box.

The packaging's dimensions are just slightly bigger than the battery box in it (it fits with little headroom, and room for a booklet). Specifically, 8 x 7.5 x 4.5 cm (ref. 88015-1 (Original Box Entry)).

Thank you. I have ordered this component. I will confirm the dimensions here after I receive it.

I received the component today. The exact dimensions are 43 mm x 72 mm x 77 mm.

source: Stack Exchange

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

sort: votes


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LEGO Express 60197 displays low battery
Using new batteries to power the controller - however on connecting the app using Bluetooth the status immediately shows low battery.
Uninstalled the app and reinstalled it with new set of batteries, but no change.

Are you using rechargeable batteries? Rechargeable batteries have a lower nominal voltage (6 batteries is only 7.2V rather than 9V) and hence the hub will report the batteries being low much faster. The powered up team indicated that rechargeables should work, but perhaps thats false.

all_licenses: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/


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Which LEGO set is this vehicle assembly from?
I found this in my LEGO box. I’ve looked up the brick numbers to try and identify, but I can’t for the life of me figure out what set it’s from or a part of. Looks fairly recent, though I have LEGO sets that are at least 30+ years old. It’s not something I would have built without a plan. Would appreciate the help! I’d like to find the rest of the parts and finish it!

It is a 4x4 from Extreme Team Challenge (6584) set released in 1998.


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Should the LEGO Batcave step 264 use 1x1 Technic bricks?
I've been building the Batcave – Shadow Box (76252):

I have gotten to step 264 and it seems odd to me that the single back bricks have a hole in them as they seem to go in sideways in the picture blocking the holes - hence only a single solid brick was really needed?

This is likely correct. Here's the instruction step that you mentioned:

In order to keep costs lower, TLG tries to limit the number of unique elements in a set and in an individual bag within a set.
The part you mentioned could have been a 1x1 system brick, but using a Technic brick here also works fine. Bag 9, the bag used for this step, already includes 1x1 Technic bricks as they are needed for subsequent steps, such as 265:

None of the other steps related to bag 9 use a 1x1 System brick. It is likely that the 1x1 Technic brick was used in step 264 in order to avoid having to include another element in this bag.

As well as keeping costs low, it also reduces the risk of using the wrong part by mistake, leading to much frustration later in the build

@MatthewJensen UGH, you just gave me flashbacks to building the Colosseum.  I think I averaged 2 wrong bricks or plates per 3 segments of the build.


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Which LEGO set is a gray vehicle frame from?
I bought a bag of LEGO in 2020, there is a frame which I think belongs to a vehicle. I have tried to search for the gray bricks with holes of 14x1 , but I could not identify the set. I might make a mistake with the color. Can anyone can identify the set from the photo? Any help is greatly appreciated.

This appears to be set 75086 Battle Droid Troop Carrier.


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Unable to open port error
Since today, no matter what program that uses sensors I try to run on my EV3 I get the following error:
lejos.hardware.DeviceException: unable to open port
    at lejos.internal.ev3.EV3Port.open(EV3Port.java:75)
    at lejos.hardware.sensor.AnalogSensor.<init>(AnalogSensor.java:24)
    at lejos.hardware.sensor.AnalogSensor.<init>(AnalogSensor.java:35)
    at lejos.hardware.sensor.EV3TouchSensor.<init>(EV3TouchSensor.java:61)
    at ia.Sensor.<init>(Sensor.java:19)
    at ia.Robot.<init>(Robot.java:16)
    at ia.Jeu.main(Jeu.java:16)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at lejos.internal.ev3.EV3Wrapper.invokeClass(EV3Wrapper.java:62)
    at lejos.internal.ev3.EV3Wrapper.main(EV3Wrapper.java:46)

I've checked the ports, the cables and my ultrasonic sensor (which seems to be where the problem is) but nothing. I get the same error when I try closing the sensor.

This is a stack trace. What is the actual error? Are you using LeJOS firmware or ev3dev-lang-java?

@DavidLechner Sorry, I didn't paste it correctly, it should appear now. I'm using ev3dev-lang-java.

Do the sensors show up in the in the "Device Browser" on the EV3?


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What can I do to use my RCX brick?
I got this old mindstorms invention system 2.0 and I can't get the tower to connect. I have the right battery and adapter and a working brick. I have tried the Bricx program and it is not working. I don't know much about the situation, so I'm sorry for any lack of information.
I'm wondering if its because I have a 2.0 tower and a 1.0 brick? Or maybe my tower is broken. Is there any sign of the tower being on?
Please tell me if there is something I need to do.

Hi Joey, do you have a LEGO serial tower or a LEGO USB tower? You could open a serial terminal program and check if the transmissions are echoed back.


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Which LEGO set is this from?
I recently bought a second hand LEGO set which contained 1 random sealed bag from another set.
Its bag #3, the QR code on it gives number 6171968. Can anyone identify the set from the attached photo?
Many thanks!

Based on

White Plate, Modified 2 x 3 with Hole
and
Tan Brick, Round Corner 3 x 3 x 2 Dome Top

this would be from
41349: Drifting Diner

Very much appreciated, thank you.
Now to find out how to get the other bags in the set / whether it’s worth it!!

Hi @Richard, if an answer has helped you, please click the tick mark next to it. That tells the system (and other contributors) that the question has been answered satisfactorily and is not looking for additional answers. See more in the [help], specifically here.


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Recognize these white and gray ships?

I want to get missing pieces but don't know Lego set number.

The top ship looked like a Star Wars X-wing, and after a bit of searching it can be identified as set 75218:

Notably, the stickers in its sticker sheet match your photograph:

Based on trans-blue 2x2 radar dish alone, the smaller ship can be identified as set 8085 "Freeco Speeder":


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DUPLO train engine base part# 28743 engine is not working
I've went through all of the steps here:
How to disassemble the propulsion wheels of the LEGO/DUPLO train engine base part# 28743 drivetrain?
which was a great learning exercise but unfortunately it seems like the actual motor itself has kicked the bucket. I can hear it activating when I try to push start it and kick it off from Bluetooth. It even works for a half a second.
Any idea where you can get a spare or even people who have been able to go in and fix it?

Bricklink is often the best place to find individual LEGO and Duplo parts.  The 28743c01 "Duplo, Train Locomotive Base Push & Go Motor" is currently available 18 times from $17.04 to $53.99.  This is perfect if you just want the one part and you don't want to deal with other new parts.
Bricklink also has new-in-the-box sets that include this part such as the 10874-1 Steam Train for $41.08.  Getting some extra parts and having it all be new-in-the-box sounds like a better deal to me.  This motor was in a total of 3 sets, so you may prefer one of the other two Duplo trains that have this part.


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Identify this part, looks like a black handheld controller
Does anyone have information about this LEGO item?
It appears to be an infrared controller.  Maybe for an old LEGO train.

A quick image search points to part 40529c01, which appeared only in two sets from 2006: 7897-1 Passenger Train and 7898-1 Cargo Train Deluxe.

You are making me feel old, I'd consider that part of a relatively new train ;) I'll try to put your train into context by briefly describing what came before it, then describing the system you have, then briefly describing what came since.

In the pre-9V era there were 4.5V and 12V trains. The main rails were blue or grey plastic and sleepers and rails were supplied separately. The blue rails just used ordinary lego studs to attach to the sleepers, while the later grey track added special clips for more rigidity. The 4.5V trains were battery powered and controlled by physical switches on the train while the 12V trains used a central rail.
When trains came into the "Electric system 9V" era, the system was radically redesigned. The separate plastic rails and sleepers were replaced by single clip-together panels of track, with metal-covered rails. Trains were powered via the rails from a mains powered "transformer and speed regulator".
This system lasted a very long time with sets released all the way from 1991 to 2006.

Towards the end of the "Electric system 9V" era, Lego introduced a couple of trains with infrared remote control instead of track power. This is what you appear to have one of the parts of. There were three main functional components to the system.

The remote control which you have.
The train motor. This was similar in size and shape to the previous 9V train motor, but the electric wheels were gone, it had to be powered by a cable within the train.
The "train base". This contained the infrared receiver and the battery box. It also had the main chassis plate for the train to which the train motor and the free-wheeling bogie would be clipped.

Alongside this Lego introduced a new type of track. This was non-conductive, but was made out of fixed panels similar to the 9V electric track. The new plastic track connected together with the 9V electrified track so both could be used for the new infrared trains.
This system did not appear to last long, it appears there were only ever two sets made, both released in 2006. The train base made the system inflexible, giving little choice in the design of the train. The motor also seems to have been released separately as an accessory in 2009.

The next revision of Lego trains kept the plastic track but switched from "Electric system 9V" to "power functions". This system split the infrared receiver from the battery box, allowing more flexibility in train design (and also allowing the same parts to be re-used in train and non-train applications). This lasted longer than the first generation of RC trains, though not as long as the 9V track powered trains, with sets released in 2010 to 2015.
The current revision of Lego trains, with sets released from 2018 to 2022, moves to the "powered up" system. This re-integrates the receiver with the battery box, but it uses Bluetooth instead of IR, so the receiver doesn't need line of sight.

"I'm not sure if the new plastic track would clip together with the 9V electrified track or not." They certainly did.


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Finding minifigs in a specific theme
A couple of times I've been asked by people what is the cheapest or easiest way to buy some random complete minifigs in some theme.
For example:

they have a couple of fairground sets and they want to create a diorama populated with minifigures is summer/leisure attire...
they have a winter village they want to populate with minifigs that are warmly dressed...
they have a shopping mall or business district, they want minifigs in more formal attire...
some workers on a construction site...

They usually don't want to spend the time picking out individual minifig elements, just some random complete figs with some restrictions on their attire and preferably as cheap as possible.
What would you recommend to these people?

BrickLink has minifigures broken out by category and many people sell them this way because often the minifigs are the most valuable part of a set.  The biggest problem I foresee in using this method is that the categories might not line up with what you are looking for very well.  You might need to search through a few categories to find all of the options.

Where I live, Brisbane Australia, we have BrickResales online as well as an actual shop. They often sell packets with six or eight minifigs relating to a theme. I've purchased half a dozen construction workers in one lot, for example. Have a look in your area for similar.


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Identify my old motorbike
My old motorbike part, I want help to identify please.

BrickLink calls it a Fabuland Scooter. In white, it seems to have been in two sets.

Thanks RSchulz
for your help !!!

@Georgios If RSchulz answered your question, you should accept their answer with the check mark to the left.


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Fixing a LEGO M Motor connector
I have several broken "Powered Up" M motors and I took one apart to see what was wrong. I ended up snipping off a section of the wire and re-soldering it back together but testing with an Ohm meter results in infinite resistance between the connector pins and the soldered points in the motor. So I took the connector apart (nearly destroying the thing), and I removed the wire and snipped an inch off. Using an Ohm meter now shows 0 resistance through the wire.
I have a problem putting the connector back together now. I put the pins back in place on the plastic pieces and then pressed the plastic pieces back in place with the hopes that the metal pins pierce the wires and allow for electricity to flow. It's not working.
Anyone here have any experience putting the connectors back together or pointers to resources on how people did it? I haven't found anything so far applicable for the M motor.

A quick search sends me to https://www.biasedlogic.com/index.php/lego-powered-up-connector/ - it's possible to 3d-print a new male connector and solder it.

I thought about the 3d printing too. Just adding the wire to the connector though is very difficult because the pins have these little spikes that pierce through the wire to complete the circuit.

You mean the male connectors have to be crimped, like male RJ45 connectors? The usual way to repair a crimp-on connector is to just replace it with a new one, and apply a specialized tool to crimp. :-(

I think I kind of got it. I pressed down really hard and the wire did get pierced by the spikes on the bottom part of the connector. The top spikes aren't working but I think I'll let that slide.

Can you share a picture?

Have you tried asking LEGO for a replacement?


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Would this be a Star Wars ship? It's full of greys, has round bits on the sides, and a trap door on top
I cannot find which set this is.

Based on

Dark Bluish Gray Slope, Curved 4 x 1 x 2/3 Double
Light Bluish Gray Plate, Modified 6 x 8 Trap Door Frame Horizontal (Long Pin Holders)

It looks like 75152-1 Imperial Assault Hovertank


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Identify bricks, similar to LEGO without bottom tubes
I have a box of bricks with some age, that I'm unable to identify.
They have some numbers on the inside which don't help and no identifying markings. I thought they could be by Halsam, however that is not the case.


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Converting Nanobocks builds to LEGO
Had anyone attempted and had any success in converting a nanoblocks build to use LEGO bricks?
On the horizontal plane, the nanoblocks bricks seem to be half the size of LEGO bricks (4mm x 4mm versus 8mm x 8mm), so a purely 2D model could be simply reproduced at double (or four time considering the area) the size.
However, I am finding it harder to determine how to scale the two vertically - nanoblocks quote a height of 5mm, but this is to the top of the stud rather than the height of the brick, which seems to be roughly half as high. This means nanoblock scaled up to the same width would be half the height of LEGO bricks. So perhaps replacing every nanoblocks 1x1 brick with a LEGO 2x2 would work?
Another problem is that nanoblocks produce a 'T' shaped piece which LEGO is missing, but this could be much easier to work around.
Has anyone experimented with this and have any conclusions?
[I'll tag this with clone brands, but I don't think nanoblocks actually qualifies as a clone (different size, not compatible)!]

I was thinking that Nanoblocks are the same height as Lego plates, not counting the stud. I've built a church from Lego, then tried to build one just as big using Nanoblocks: it having a 30-brick tall tower, but found it to be about 1 brick short, so I estimate Nanoblocks are 3•1mm tall which is what it says on LNO Nanoblocks box, with double height 6•3, guess they expect a 0•1 gap. The 5mm given as their height includes the stud.
So 2 Lego plates will be just over twice as tall as Nanoblocks. One may as well do each level of Nanoblocks as the 2 Lego plates levels using joins in differing places. 1st layer Lego plate, then bricks where also wanted for 2nd layer of Nano, then finish 1st layer Nano with 2nd layer of Lego plate, or maybe start with bricks.
Kawada Nano Block of Japan don't use tubes, but a ridge. This lets the brick below to be positioned anywhere along its length. It is the same with the 1×x pieces as they have no bars. Lego tiles 1×2 with 1 stud & 1×3 with 2 studs can position under their studs if they have groove.
Looking at building a Lego elephant from Nano instructions, it uses 1×4's with round ends. These Lego plates are only in 1 set. To be able to move the ears back to ~45°, I considered using hollow bricks, so square end bricks could turn like a round 1 can. A panel corner 1×1 does the job & needs to be mounted 1 plate lower so the corner of the brick is over its base.
Back of Lego elephant, black = 1×3 +2 studs & groove, white = 1×2 +1 stud & groove, yellow = 1×2 +1 stud normal & grey = 2×2 corner. There be 2 ways of doing the top part of legs. Used plate 6×x & so not hollow. Nano, red when I've not dark gray, 2×2 corner as not Kawada.
Photo of orca (killer whale), I do not have the right Lego ball joints, see 1 full brick on fin, some clone brand, 2nd black from front are 2 1×3's with 2 studs with 1×2's atop (I've none for the Nano, so got there a 1×3 atop).
As for T shape, as 2 layer, 1 using 1×3 & other 2×2 corner both with a 1×1.
Bulldog, from Wise Hawk, full brick for mouth with top part hidden for Lego.
With the beagle dog there is a 1×2 at 90° under centre of a 1×4, as can't be seen can use a 1×2 with holes as its hollow studs fit to bars. Maybe use a 1×2 slope. (Has a 1×1 atop, so full brick & plate for 2 Nano.)
Cow's udder, this = 2×3 central under 3×4, if 3×4 brick used then no problem as 2×3 fits to tubes, but slope or 2 of 2×3 wedge won't do, with 1 row of studs okay. Other way is 1×3's with 2studs across mid 2 'then 2 other way under,

Hi Andrew, I tried to fix up your answer, but at certain places I could only guess at your intended meaning. Please take a look at my edits and fix anything I might have gotten wrong or missed altogether. And I'd appreciate if the next time you could use a bit more professional language, including but not limited to proper punctuation, complete sentences and full words. That way your intention would be clear even without copyediting. Thanks!

If you want more exact measurements, this Nanoblock vs Lego article shows the exact figures for 1x1 pieces from each brand, not including the studs:
Nanoblock: 3.8 x 3.8 x 3mm
Lego: 7.8 x 7.8 x 9.6mm
That means they're just under half the width and 1/3 the height.
However, you can also see from the images in the link that a standard Nanoblock piece is just a hair shorter than a standard Lego plate (3.2mm), not including the studs.
Therefore, if you simply use two stacked plates instead of standard-height Lego pieces, you can easily replicate Nanoblock builds using Lego by doubling the other dimensions. This is also a better solution to match color profiles.
Of course, this doesn't solve other problems, like the lack of L-shaped pieces and different locking mechanisms, but those should be easy to overcome with a few simple design changes.


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What is the carbon footprint of running a Spike Prime robot?
We are trying to calculate how much carbon is emitted from running a Spike Prime robot off one charge (roughly 8-10 hours)?

I dont’t think Bricks.se.com is the right place to get answers to homework questions,

I’m voting to close this question because this is asking the community to complete a homework assignment

no, answers are here

@PhilB. Even if the question is about a homework assignment, it has a clear connection to LEGO bricks with a less-known but exactly available data (the total amount of energy in a SP battery), which is essential to calculating the answer. Providing this information would be squarely in the focus of Bricks.SE - but solving the assignment on the other hand is of course not. I'd suggest editing the question to emphasize this information need.

None, running the robot doesn't produce any carbon as it doesn't run on fossil fuels but consumes electrical energy.
Producing the electrical energy to charge the battery does have a carbon footprint, so I'm going to assume you meant to ask that.
I'm also going to assume that you completely deplete the battery before you recharge it.
Specs say that the battery capacity is 2100 mAh at 7.3 V...
Hence, power usage is 2100 x 7.3 / 1000 = 15,33 Watt hours (Wh) = 0.01533 kWh
How much carbon is emitted depends on how the electricity to charge the battery is produced, which basically depends on how electricity is generated where you live.
assuming you are from the US I found the following data:
https://www.eia.gov/tools/faqs/faq.php?id=74&t=11
Which states that 0.855 pounds of CO2 is produced per kWh
So I get 0.01533 kWh times 0.855 ~=~ 0.0131 pounds = 0.209 ounces

Thanks for this answer!

The official rechargeable battery for the large hub has 2100mAh capacity at 7.3V - This lets you calculate the total watt-hours in one full charge (let us know if you need help with this), which you'll then need to multiply by the CO2-factor of your current local energy provider.
This last part makes the question ultimately not answerable in a universal way, as you'll get entirely different results if the electricity you use comes from a hydro power plant or from a plant burning brown coal.


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Lego Mindstorms EV3 broken screen cable
While taking apart my EV3 brick I accidently pulled on the ribbon cable connecting the screen to the motherboard too hard and it broke.
I figured I could just get a replacement fpc ribbon cable with the same number of pins and swap out the cable, but turns out the other end is soldered to the screen, so that isn't going to work.
I looked around a lot on the Internet and found several other people with the same issue, but no solutions to the problem. Any advice on what I can do from here?

First of all: before doing anything else, contact LEGO customer support. There's nothing to lose by doing so.

According to the video at https://www.youtube.com/watch?v=gPNJC5Uz9HY , it's possible to replace the screen with a 1.8 inch colour TFT display with the aid of a flat ribbon adaptor.

I'm unsure if you would need to replace the Lego firmware with https://www.ev3dev.org/ or not.

Edit: Lego offers electronic schematics of the EV3 as part of the "Hardware developer kit" that can be downloaded from https://education.lego.com/en-us/product-resources/mindstorms-ev3/downloads/developer-kits . It tells us that the display connects through SPI, and contains this diagram of special relevance:

You should be able to connect any SPI display, which would need 5 connections: +3.3V (or VDDA), 0V (or GND), clock (CLK), MOSI (or DIN or RX in a SPI peripheral), and CS (or SS). Be aware that the nomenclature for SPI is confusing. The screen does not send data back to the board, so a MISO/DOUT/TX connection is not needed.
The stock firmware should work with any monochrome SPI display, but we hobbyists cannot offer you any guarantee at all.

Anyway, the original screen seems to use a pretty standard 18-pin 1.0mm-pitch ribbon cable. You should be able to unsolder it and replace with a new one. But since the connector at the board is a 18-pin 0.5mm-pitch, you'd need to use an adaptor like the aforementioned one.
Bear in mind that soldering tracks with a 1.0mm pitch requires precision soldering skills (and you can imagine that 0.5mm pitch will just be harder). I strongly recommend practicing your soldering skills first.

Edit: According to the folks over at the Electronics stackexchange, it's possible to repair a flat ribbon cable.

Thanks for your reply Ivan. I did go through that video earlier and it seems like the stock firmware doesn't support the color LCD display. I wanted to know if it was possible to get a screen that is similar to the existing one and works directly with the stock firmware. I'm not very experienced with electronics like these so it'll be quite difficult for me to figure out what wiring goes where, but I'm open to learning.

I think I added enough information about wiring to get you started.

Yes. The added information is of great help. I’ll do some more reading on this and get back to you. Thanks a lot!

I was also wondering if screen size would be an issue. The stock display has a resolution of 178x128 pixels, which seems to be custom designed for the EV3, and I can't find that screen size anywhere. The closest I can find is a 160x128 pixel display. I'm assuming that the EV3dev kernel can adapt the display contents to the screen resolution, which is why it worked with the adafruit 160x128 LCD display (in the video you linked), but I'm not sure if that is the case with the stock firmware. Any idea about this?

Alas, I haven't worked enough with SPI displays to know that. You might wanna ask in https://electronics.stackexchange.com .


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Why does my 60198 train get lots of wheel spin?
I was running my 60198 train with the 60197 carriages attached (carriages from 60198 also on the train). My train has started to get lots of wheel spin even while on flat ground. What can I do?

Slipping of a wheel is caused by a too low friction between the wheel and the surface. The most straightforward solution would be to reduce the mass of the carriages the locomotive has to pull, but that would be the least desirable too as you probably want to keep all currently attached carriages.
The other solution would be to increase the friction, for this you have two ways. The first is to increase the gripping forces between the wheel and the rails, for example by adding a rubber band or a thin piece of rubbery plastic (duct tape?) to the rim of the wheel. Texturing the wheel and/or the rail surface would work too, but you probably don't want to damage your pieces that way. The second way to increase friction forces is to add more mass to the locomotive itself, preferably directly above the wheels. This will increase the weight (downward acting force) pressing the wheels to the rails.
An additional, out-of-the-box option would be to convert one of the carriages into a support locomotive, thereby distributing the forces experienced by the drive wheels across more wheels.

Would it be possible to increase the traction by adding weight to the locomotive?

@IvanSanchez "The second way to increase traction forces is to add more mass to the locomotive itself, ..." from the answer already suggests doing just that.

As a more specific suggestion, I can attest that thin rubber O-rings work wonderfully for increasing traction, and they visually blend better with the black wheels found on 60198 (one of my friends had exactly the same issue with one of his builds using the locomotive from 60198, and this was his solution). And, with a bit of leg work, you can find ones that are exactly the correct size for this, which will help them last longer than something that needs to stretch out would.

There is a third option as well, which is to reduce the acceleration. A locomotive that tries to accelerate very quickly will just spin its wheels, but even a train with very little friction in the wheels can accelerate without slipping, so long as it does so gently enough. This solution requires changing nothing about the train itself, only how it's driven.

For a locomotive counterweight, you might consider the 73090a 2x6x2 weighted brick https://www.bricklink.com/catalogItemIn.asp?P=73090a&in=S
Bricklink shows them with train sets, but I never had any of the sets they list - I think mine was from a floating boat kit: 4011 Cabin Cruiser.

Welcome to Bricks.SE, Chris! Thank you for a great answer, hope you'll enjoy contributing to the site. Feel free to browse the [help] and [tour] pages if you have any questions. A quick advice: all posts have a transparent edit history, so it's unnecessary to mark your edits as such if not for avoiding confusion (e.g. when editing a post as a reaction to someone's feedback).

Thanks for the edit pointer.


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Need help identifying an unopened LEGO bag - lime green and black pieces
We found an unopened bag of lime green and black pieces. Son does not remember what or where it came from which is odd because he's always eager to assemble sets when he gets them. Looks like some sort of vehicle since there is a windshield, wheels and steering with pieces that are smooth on the outside.

I fixed the photo links - if I had done that first, it might have been easier to find, as I only went off the first photo.

76899-1 Lamborghini Urus ST-X & Lamborghini Huracán Super Trofeo EVO
Based on

Black Brick 1 x 10
Lime Plate 1 x 6
Lime Slope, Curved 8 x 2


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What are these magnetic LEGO-like bricks?
Can anyone identify these? The tin they are in is dated around 1967 so bricks might be of a similar age. They are magnetic.
Any help greatly appreciated.

According to this article these are called "Bombo Magnet".

Bombo Magnet-1963.
Bricks made of a metal plate with studs, a magnet, and its plastic cover. The plastic "grid" on the underside leaves exactly room for the elevations of the upper metal plate ensuring that bricks can be built precisely on top of each other. First presented at the 14th Toy Fair in Nuremberg. Made by: BOMBO GmbH in Bad Honnef am Rhein, Germany.

Amazing. Thankyou very much!


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What will the size of finished set be?
How can you tell from information on the box or manual what the size of the finished set will be? I'm thinking of space needed to create and store, etc.

Modern largest sets usually state on the box how big they are. But this isn't a case for smaller sets.
However there is another option. Based on brick dimensions it is possible to estimate the size of a set. Assuming set is built in traditional "studs up" approach:

each stud on horizontal plane would be 8mm
each brick on vertical plane would be 9.6mm, where each plate is 3.2mm.

Bricklink (and other sites) give dimensions of most elements in studs, but looking that up for each element in a set is probably a major task - and given the number of ways elements can be combined and the amount of air "trapped" in models, I doubt that the size of the elements can be used to estimate the size of the finished set.

@Henriksupportsthecommunity I don't see where your concern is coming from. It is fairly easy to roughly calculate everything in studs/bricks and later convert to Metric/Imperial system.

Yes, but even though we know the dimensions of an e.g. 2x4 brick, that doesn't tell us much about the dimensions of a "model" consisting of two of them. If the two bricks are placed fully on top of each other, we only have to add the heights, if they're combined in a different way, we also have to look at the other dimensions. And that was just with two bricks that combine in 24 different ways (several has the same size), with 6 2x4 the number of combinations rise to above 900 million.

@Henriksupportsthecommunity it seems to me we are looking at this at a different angle. My idea is that you count your bricks of final model from pictures, rather than checking the part list to estimate the variety this have and resulted dimensions. Assembly of two stacked 2x4 bricks have dimensions of 163219.2mm, same two 2x4 bricks in cross configuration will be 323219.2mm. Same goes if you have more of them, even in odd shapes.

The question does say "or manual", and I guess you can see the final model at the end of the manual. It might not be possible to see if e.g. anything sticks out of the back without going through the manual. But I guess that will work - I was thinking about estimating the size from just the box (where some size information is given for large modern sets).

LEGO shop site
In the marketing for large LEGO sets, they typically make a big deal about advertising the dimensions. In the case of the Apollo Saturn V for example you can find the dimensions under the 'Specifications' section:

Measures over 39" (100cm) high and 6” (17cm) in diameter.

You might also be able to find this on the set box.
Bricklink Studio
Bricklink Studio also has a feature that displays the dimensions and weight of models. This can be found under the menu bar 'Model' and then 'Model Info'.

If you can find an existing model of the set you are looking for you can download it and import it into the software. Of course you can also make modifications to the model or build your own too.
You can import LEGO Digital Designer files into Studio as well and there is a huge collection of fan-made models of existing sets at Eurobricks.


text:
How does the play experience work in the City Missions sets?
I recently saw one of the LEGO City Missions sets:

According to the box, these sets are "built with stories, not instructions". How does this work in practice?

I saw these on the shelf recently and wondered how they worked. TLG was kind enough to send me a copy to explore.
The experiences for this set are available in the LEGO Builder app. The box itself does not come with any form of paper instructions aside from a single page directing builders to access the app:

The app allows you to select a set and explore its missions:

The build and play experience is driven by a series of "missions" inside the app:

I initially expected these sets to be a bit like a Creator 3-in-1 sets with app-based instructions and light "story" elements between certain steps based on this image from the box:

I was pleasantly surprised that there is quite a bit more opportunity for creative building here than I initially assumed. The first mission allows builders to create a couple minifigs with a few accessories. There's not a huge amount of creativity involved here, but you can mix-and-match minifig parts.
The second mission provides the build for the core element of the set and is built using regular in-app instructions. This provides the structure for future missions and steps. Here's the completed core for the space set:

The core elements for the sets feature a few play features and numerous attachment points for accessories and modifications.
Subsequent missions provide short video and text descriptions of challenges to overcome by adding or changing features of the core set. These missions may not include additional instructions:

Builders are provided with extra pieces and high-level goals for the build (e.g. rescue an astronaut floating in space). There are also ideas provided for possible minibuilds that can be added to the main build:

Once the self-guided creative modifications have been completed, builders can finish the mission and participate in an imaginative play experience (test the booster, fly to Mars, look for clues related to a crime, rescue an animal, etc),

Aside from a brief video, the missions do not include any digital play component. This isn't a series of digital minigames between building steps. There's not much to do in the app other than follow instructions, read, and watch short videos.
As far as I know, there are 3 sets available following this format. They are:

60353 Wild Animal Rescue Missions
60354 Mars Spacecraft Exploration Missions
60355 Water Police Detective Missions

They each include a base model that can be customized with an array of parts:
Animal Rescue

Space

Water Police

In terms of the play experience, these sets feel a bit like Education sets, Boost, or Robot Inventor where the builder completes a series of builds and tasks in an interleaved manner.
As far as parts go, these felt a little bit like the 2018 Builder Bigger Thinking sets, where builders are given a variety of imaginative parts and minifigs:

For my child, it was helpful to have a base to build from and then have a palette of distinctive pieces to use for customization. Here's what they came up with:

Overall, I appreciate seeing LEGO try something a bit different in the City line by making use of some of the techniques used in more educational sets. This seems like it could be a good way to get certain types of kids more involved in creative build and play experiences.

Animal rescue seems rather lacking in actual animals - there's a rabbit that looks like a glove puppet, and a fish, but a chicken drumstick? That rescue can't have ended well, at least not for the chicken.

@ChrisH The chicken is bait for catching a bigger animal. Although, now I'm worried about the bunny...

@ChrisH Not to mention the generic bone next to the fish.  I guess that's what the drumstick looks like after you bait said bigger animal?

Good spot @DarrelHoffman, I missed that in white on white, and there must be dozens of them at my house (very common in Friends sets with dogs)


text:
Brick labels to be printed
I am new to the LEGO "business". But I am building up my inventory, getting close to 100.000 pieces now, and before shooting off, I want to have my "system" organized. That also includes print off labels for every small part, to glue on the separate box/draw for item. This makes it easier, and more safe for proper work by several people, assuring that the right part is picked.
But, where do I find info about this? My wish is to print a few, important key words about the part - part.no., picture...
Any suggestions?

Tom Alphin has a template of labels you can download and print with the appropriate label printer.
Sample:

You can try to use www.bricklabels.com
It allows you to select which parts you want to print and allows you to print the labels in your custom size, fitting the drawers perfectly.

Full disclosure: I made the app :-/, but it's free and open-source: https://github.com/Gottwik/legolabels

This looks great! Thanks for building this and sharing it here!

Wow, thanks for the encouragement. Let me know if something doesn't work or you would like more features.

Since you're already using the Rebrickable API, it would be cool if this imported a users parts so that they don't have to manually enter everything. If you include filtering, this could make it trivial to do something like print a label for every gear element that a user owns.

That's a good idea. I will sure implement this. I would often reprint labels when the container got too small as the amount of bricks increased or as I got some new parts, so it was always easy to just input the part id from the previous label and reprint it.

@MartinGottweis Just to point out, when I click on the link you pasted (http://www.bricklabels.com/), I end up at a GoDaddy landing page. Maybe you forgot to renew the domain??

I would start with looking at the way Bricklink has their catalog organized, or look at LDraw's catalog. They have a fairly basic system segmenting LEGO into bricks, plates, tiles, beams, rods, minifigs etc. Should get you going.
EDIT: And if you really want to ID each part, just use the Bricklink part numbers (same as LDraw's numbers) to print on the bins. The Catalog feature should help you getting those, once you are familiar with the Bricklink naming schedule.

Hi;  I dont' want to ID mark every part, I want to ID mark every box where I put the certain item.

Ok - then never mind my edit.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/3.0/


text:
Help with this .nxc Tripod program
I am getting a file error when I try to run this on my NXT 2.0. It's my first time using NXC and the program compiles and transfers fine...
I tried replacing the batteries, the only other thing is that I thought maybe there was a firmware problem. Only thing is, I'd rather not get a custom firmware if I don't have to.
/**
 * Tripod walker
 *
 * Description:  This the Tripod program, to make it walk, turn, and avoid obstacles
 *
 * Notes: Compile for 2.0 NXT firmware (1.028)
 *
 * @author Daniele Benedettelli, MCP http://robotics.benedettelli.com, Copyright (C) 2012.
 *
 * @see The GNU Public License (GPL)
 */

/*
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
 * for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

#define STEP_PAUSE 80

#define LEFT_LEG OUT_C
#define REAR_LEG OUT_B
#define RIGHT_LEG OUT_A
#define EYE IN_4

#define NEAR 25
#define NONE -1
#define LEFT 1
#define RIGHT 2
#define FRONT 3
#define BACK 4

#define CW 1
#define CCW 0

#define KP 30
#define KD 10
#define KI 0
#define DAMP 60
#define SCALE 5

#define MID 60

int ref[3];

void Set(byte rear, byte left, byte right)
{
   ref[REAR_LEG] = rear;
   ref[LEFT_LEG] = left;
   ref[RIGHT_LEG] = right;
}

void Pulse(byte motor, int times, bool long_pulse)
{
   repeat (times)
   {
      ref[motor] = MID+10;
      Wait(80);
      //Wait(70+long_pulse*30);
      ref[motor] = MID-10;
      Wait(80);
   }
}

void PulseDouble(byte motor_one, byte motor_two, int times, bool long_pulse)
{
   repeat (times)
   {
      ref[motor_one] = 80;
      ref[motor_two] = 80;
      Wait(50+long_pulse*40);
      ref[motor_one] = 40;
      ref[motor_two] = 40;
   }
}

void Walk (int dir, int times)
{
   repeat(times)
   {
      if (dir == FRONT)
      {
         Set(MID-20,MID,MID);
         Wait(300);
         Set(MID+10,MID,MID);
         Wait(200);
      }
      else if (dir == BACK)
      {
         Set(MID-10,MID+20,MID+20);
         Wait(150);
         Set(MID-10,MID-10,MID-10);
         Wait(300);
      }
      else if (dir == RIGHT)
      {
         Set(MID-10,MID-20,MID-10);
         Wait(80);
         Set(MID+10,MID-20,MID+10);
         Wait(150);
         Set(MID-10,MID-20,MID-10);
         Wait(300);
      }
      else if (dir == LEFT)
      {
         Set(MID-10,MID-10,MID-20);
         Wait(80);
         Set(MID+10,MID+10,MID-20);
         Wait(150);
         Set(MID-10,MID-10,MID-20);
         Wait(300);
      }
//      if (times>1)  Wait(STEP_PAUSE);
   }
}

void Turn(int wise, int times)
{
   repeat (times)
   {
      ref[REAR_LEG] = MID-10;
      ref[wise==CCW? RIGHT_LEG:LEFT_LEG] = MID+10;
      Wait(100);
      ref[wise==CCW? LEFT_LEG:RIGHT_LEG] = MID+10;
      ref[wise==CCW? RIGHT_LEG:LEFT_LEG] = MID-10;
      Wait(100);
      ref[wise==CCW? LEFT_LEG:RIGHT_LEG] = MID-10;
      ref[REAR_LEG] = MID+10;
      Wait(100);
//      Pulse( wise==CCW? REAR_LEG:LEFT_LEG, 1, false);
//      Pulse(RIGHT_LEG,1,false);
//      Pulse( wise==CCW? LEFT_LEG:REAR_LEG,1,false);
   }
}

void Demo()
{
   Walk(FRONT,10);
   Turn(CCW,10);
   Walk(FRONT,10);
   Turn(CW,10);
   Walk(FRONT,10);
   Walk(LEFT,10);
   Walk(RIGHT,10);
}

task motorAcontroller()
{
   int err, P, I, D, PID, Apos, Aold;
   ResetAllTachoCounts(OUT_A);
   ResetRotationCount(OUT_A);
   while(true)
   {
      Apos = MotorRotationCount(OUT_A);
      err = Apos - ref[OUT_A];
      P = KP*err;
      I = err + KI*I*(100-DAMP)/100;
      D = KD*(err-Aold);
      PID = (P + I + D)/SCALE;
      PID = abs(PID)>100? sign(PID)*100 : PID;
      OnRev(OUT_A,PID);
      Aold = err;
   }
}

task motorBcontroller()
{
   int err, P, I, D, PID, Bpos, Bold;
   ResetAllTachoCounts(OUT_B);
   ResetRotationCount(OUT_B);
   while(true)
   {
      Bpos = MotorRotationCount(OUT_B);
      err = Bpos - ref[OUT_B];
      P = KP*err;
      I = err + KI*I*(100-DAMP)/100;
      D = KD*(err-Bold);
      PID = (P + I + D)/SCALE;
      PID = abs(PID)>100? sign(PID)*100 : PID;
      OnRev(OUT_B,PID);
      Bold = err;
   }
}

task motorCcontroller()
{
   int err, P, I, D, PID, Cpos, Cold;
   ResetAllTachoCounts(OUT_C);
   ResetRotationCount(OUT_C);
   while(true)
   {
      Cpos = MotorRotationCount(OUT_C);
      err = Cpos - ref[OUT_C];
      P = KP*err;
      I = err + KI*I*(100-DAMP)/100;
      D = KD*(err-Cold);
      PID = (P + I + D)/SCALE;
      PID = abs(PID)>100? sign(PID)*100 : PID;
      OnRev(OUT_C,PID);
      Cold = err;
   }
}

void triped_init()
{
   //SetSensorLowspeed(LEFT_EYE);
   //SetSensorLowspeed(RIGHT_EYE);
   SetSensorLowspeed(EYE);
   OnRev(OUT_ABC,20);
   Wait(80);
   Float(OUT_ABC);
   Wait(500);
   start motorAcontroller;
   start motorBcontroller;
   start motorCcontroller;
   //Set(MID+40,MID+40,MID+40);
   //Wait(1000);
   Set(MID,MID,MID);
   Wait(1000);
   /*
   repeat(3)
   {
      Set(MID,MID+20,MID+20);
      Wait(200);
      Set(MID+20,MID+20,MID);
      Wait(200);
      Set(MID+20,MID,MID+20);
      Wait(600);
   }
   Set(MID,MID,MID);
   */
}

void Jump( int times )
{
   repeat (times)
   {
      Set(90,90,90);
      Wait(1000);
      for (int i=90; i >=30; i--)
      {
         Set(i,i,i);
         Wait(1);
      }
      Wait(1000);
   }
}

task main()
{
   int count;
   triped_init();
   while (true)
   {
      if (ButtonPressed(BTNCENTER,true))
      {
         Set(MID+50,MID+50,MID+50);
         while(ButtonPressed(BTNCENTER,true));
         until(ButtonPressed(BTNCENTER,true));
      }
      if (SensorUS(EYE)>NEAR)
      {
         Walk(FRONT,1);
      }
      else
      {
         Walk(BACK,3);
         count = 0;
         while(SensorUS(EYE)<=NEAR && count<20)
         {
            Turn(CCW,3);
            count++;
         }
         if (SensorUS(EYE)<=NEAR)
         {
            count = 0;
            while(SensorUS(EYE)<NEAR && count<20)
            {
               Turn(CW,3);
               count++;
            }
            Walk(LEFT,4);
         }
         else
         {
            Walk(RIGHT,4);
         }
         //Turn(CCW,5);
      }
   }
}

the error

@jdv "File error" on the NXT, literally... here, take a look - http://imgur.com/kzjuc0N

@jdv It could be a memory error, because I've got a bunch of other stuff on there. I'll check a simple program later.

Scratch the possible memory problem. I deleted huge amount of stuff, and the error is still exactly the same.

I got this to work. Set the optimisation level to 1 on the NBC/NXC tab of the compilation options. Then recompile and download.

I had the exact same problem when I built the tripod. This program is written in BrickCC, instead of the standard NXT-G. The way to solve this is to download and install the compiler for brickCC, which can be found by browsing the tripod section on robotsquare here.
Sources: robotsquare.com

Umm, I used BricxCC 3.3.8.9 to compile and transfer the program.

Oh. Ok. Um. I haven't got anything else.

all_licenses: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/3.0/


text:
LEGO minifig authenticity
I bought 3 mini figures from Amazon because I wanted specific mini figures and did not want to spend $30 plus doing so with bag ordering and opening. I got the figures and they look authentic.
The LEGO logos are on the nub of the torso and the little bridge part of the legs. However, not on the bottom of the legs.  I have 20 something minifigures that I opened from bags, they all have the logo on the bottom of the legs.  So I'm a little confused by it?

Can you share a picture of the minifig? Or even better - comparing it with a confirmed LEGO minifig to show the perceived differences?

Some of the minifig parts that are officially made in China (often including the Collectable Minifigures) don't have the copyright/logo stamp on the inside toe - I noted that in a comment to my answer on What does the imprinted information inside bricks mean?

I would say that it all depends on the age of the piece. Throughout lego history they have changed through various different manufacturing methods. one of the biggest being the change from yellow to skin colour and some smaller ones being the ventilation on top of the head. It would also provide a lot of help with an addition of a picture.

There is a bootleg version of lego from china. If the minifigure print wears off in a few days, its  probably bootleg. It is probably made by lele, sheng yuan, or sluban.


text:
EV3 Programme won't load to brick
I have installed EV3 on my PC and am trying to load a program into an NXT 1 Brick.
When I click the down load button on the EV3 screen the Brick beeps twice and the program does not load.
What am I doing wrong?

Did you check if there aren't any logic problems like for example putting a motor in a infinite loop with no end?

EV3 software can be used with the NXT brick. It may require a firmware update. I think firmware 1.31 is the minimum.


text:
I need a block that can combine a movement program with NXTbee radio
I am a student. I am working on a science project using LEGO Mindstorms robots enhanced with NXTbees creating a mesh network.
My engineering mentor has me using LabVIEW. I am trying to find a block that can combine a movement program (senses a block in the robot path, stops, then change direction) with NXTbee radio.
I want the NXTbee to override the Bluetooth in the LEGO Mindstorms program. I have tried a number of avenues seeking help, but they haven't worked out.  Can anyone help?

There is a LabVIEW block for the NXTBee. For example, here is a tutorial from the manufacturer.

For mesh you will need the series 2 XBee's I think. It is doable by putting the series 1 to broadcast mode, but series 2 can do real mesh.


text:
Help Identifying a LEGO Set from bag 7
I have a sealed bag of LEGO bricks that I am trying to identify. The bag is labelled with a large number 7. The pieces are dark blue, light gray, dark gray. It looks like there is a smaller bag of pieces within the larger bag. I took photos, but can't figure out how to add them to this post. Can anyone help me?

Hi Bethany, you should be able to press the small picture frame icon when you edit your post and upload an image to your post. It's possible that as a new user this option wasn't initially available.

Without pictures it would be extremely hard to tell, especially since both dark and light gray are very common colors. However you might be able to identify some of the dark-blue color pieces to see which set the bag is from. Dark-blue is a much less common color than the grays, so it would be quicker to identify what you have. The fact that it is a #7 bag seems to indicate that it is coming from a larger set.
What I would do is look at the dark-blue pieces and find one that is NOT a common piece (so anything that is NOT a plate, tile or brick). Then go to the BrickLink color-guide for dark-blue pieces, and find the one you have. From there you will see which sets the part comes in. Identify another 3-5 less common pieces, and you should be able to see which set the bag is from. Here is the list to all the elements that come in dark-blue: http://www.bricklink.com/catalogList.asp?catType=P&colorPart=63&v=3


text:
What is LEGO Junior?
Are LEGO Junior bricks bigger than regular LEGO?
I can't decide between Junior LEGO and Duplo for my son who is just over 3.  I had thought the Junior sets might constitute a happy medium, but am now less sure.

LEGO Juniors sets use normal LEGO System bricks.  In other words, they are exactly the same size as the "normal" LEGO bricks.
However, the Junior sets are specifically designed for younger children.  They often have large single-use pieces (for example, for walls or frames), and are generally very easy to construct.  They also limit the use of small or difficult to handle pieces as much as possible.
Depending on how advanced your son is, my guess is that Duplo is the most appropriate.  If he no longer attempts to put toys in his mouth, and can focus/concentrate on a task for a decent amount of time, and has started developing fine motor skills, then Junior would probably be the most appropriate.
For reference, LEGO labels the Junior sets as appropriate for 4-7-year-olds, but I have met only a couple 4-year-olds that I would give the Junior sets to.  Most 3-year-olds should probably be playing with Duplo.

excellent answer, though did you mean 3 yrs old in that next to last sentence? my 4 year old and his friends love lego jrs sets...seem age appropriate for age 4 to me. on the other hand many 3 yr olds dont have the dexterity for little legos nor the attention span to follow the directions. but they like the lego figures and vehicle bases...so a lego jr spiderman car would be ok for a 3 yr old imo...lego jr batcave not so much.

Lego Juniors is fine for 3-year-olds who know not to put toys in their mouths. My son, when he was three, was playing with regular System Lego (of which Juniors is a subset) and it was okay. If it's important to you that your son have things like vehicles, or minifigs, and that he build the whole set himself, then Juniors is the way to go.
Otherwise, I see Lego as a longer-term investment: most kids enjoy playing with it from 3 to 13 or later. Stuff like the Juniors kits, or Duplo, gets to be too babyish after a couple years, but the regular stuff is still good forever. So if you just want your son to build, get a box of basic bricks (regular Lego bricks, not Duplo) and let him build. There are no instructions for him to worry about.
If he has any interest or aptitude he'll be ready for the kits that say they're for 5+ or 6+ in no time, and those kits will mesh well with the stuff you've already bought.


text:
TIE Fighter instructions
Need to know what instructions go with this set. Bought them this year from LEGO store.  My kids lost the instructions. Comes with three separate bags in the set. Please help I'm trying to give it to my neighbor kid. My boys are still way too young for this set.

Welcome to Bricks.StackExchange! Do you know the set number of this TIE Fighter? Is it the First Order Tie Fighter (set number 75101)? http://brickset.com/sets/75101-1/First-Order-Special-Forces-TIE-Fighter ... Instructions for this set are found here....

LEGO have instructions for all their recent sets, and many older ones available directly from their website:
https://wwwsecure.us.lego.com/en-gb/service/buildinginstructions
There you can search for a specific set number, or search by theme ("Star Wars TM") and year of release - for example 75101 can be found here.


text:
Is it possible to build a decimal to binary converter (binary counter) with LEGO?
I have seen many papers on logic gates built with LEGO, but I want to make a decimal to binary converter. There should be a counter as an input, with each press of the counter, the output 8 block shelve changes its configuration giving a binary conversion of the count.
Please help me as to how can this be achieved or at least how should I start the project given that I am new in logic and boolean algebra!

The easiest way is to use balls falling down a series of binary switches.  The disadvantage is that you will have to reload it with balls every so often.

Hi @PGmath, Any alternative, because this approach does not work with a standard apparatus. The LEGO model should be a static model that could be implemented at a molecular level, so any suggestions/alternatives?

Yes, of course, you can
As jncraton mentioned in a comment:

The answer to whether this is possible is definitely "yes". NAND gates can be built, and the required logic can be implemented using NAND gates. The questions is primarily about how this can be achieved.

Logic gates in LEGO
As you can see here folks have put extensive work into creating logic gates in LEGO.  The article referenced has AND and NOT gates.  You would need to put those together to get the aforementioned NAND gate.  If you're not familiar with logic gates it may be surprising that NAND gates can do it all.
Binary counters
As this articles shows you can build a binary counter out of flip-flops and NAND's.  And as wikipedia shows you can make a variety of flip-flops out of logic gates.
Now put it together
I'm sorry there aren't LEGO-level instructions for making all of this happen, but hopefully those are enough leads for you to figure it out.  Good luck.  I hope you put this together and turn it into a lovely youtube video or article to show us all how you did it.  You'd probably be a hit too on the LEGO convention circuit.  You can do it.

You could adapt the following mechanical binary counter from wooden pieces to Lego
https://www.youtube.com/watch?v=uotLQjvaG34

The answer is yes: This is a "mechanical counter" with the base being 2.
Google for "mechanical binary counter design".

Welcome to LEGO Answers! The answer to whether this is possible is definitely "yes". NAND gates can be built, and the required logic can be implemented using NAND gates. The questions is primarily about how this can be achieved. Can you expand your answer to help with that?


text:
How steep a grade can a LEGO train go up?
I realize this would change based on how much weight it's pulling. How about using an engine pulling 3 cars? I'm guessing that sets available for sale now would have similar power. I have the engines from sets 60052 and 60098.
Thanks for any input you can provide.

Carriages can be very different, and as such a poor unit of mesure for weight. Typically we say that any train should be able to handle a climb of one plate for each piece of track (16 studs).

I've successfully run a single motor pulling two cars from 7938 and the locomotive all the cars from 79111 up a spiraling incline of two plates per track segment. I terminated the experiment after I ran out of track and table space. If the track was straight I probably could have pulled more weight.

Anecdotal input:
I run my 7745, 7740, 7735 (with extra carriages), 4458 (with 2 clubcars), 4563 and 4564 up a 14 brick total height using 16 sections of straight track.
On the main sections this is one brick per 16 long track section but at the top and the bottom I smooth out the incline with 2 plates and then 1 plate. (Otherwise the carriages, especially the club cars, bottom out on the track).
These are 12v and 9v models and not the Power Functions models you list so your motor and track characteristics are likely to be different.
Space limitations are the reason I use such a steep incline and I do have to make sure I keep the electrical contacts clean to ensure constant power delivery or I can get some slipping and wheelspins.
Also this is likely putting a fairly heavy load on the motors, luckily I have spares and I don't run my trains for long periods of time but I don't run my 7727 on this section of track for fear of damaging it's precious red motor!
I think this is the absolute steepest you could get away with and if you have the space, two plates or one plate per track section as suggested here and in other places on the web should be your goal.

Thanks for your input! I've been doing LEGO for a long time, but this my first foray into trains and I'm hooked.


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Where can I find a good tutorial on programming with Lejos?
I want to get started with LeJOS and use Java to check to see if an EV3 touch sensor is pressed, but I can't find any decent tutorials.  Are there any good resources for this?

The makers of LeJOS maintain a blog on WordPress: https://lejosnews.wordpress.com/ where they also give tips and write howto's. I think that is the best place to get started, apart perhaps from the LeJOS.org wiki pages which are located here: https://sourceforge.net/p/lejos/wiki/Home/.
Those wiki pages tend to have some inconsistencies between versions (some of it is not yet updated to the latest version of LeJOS EV3) but when I got started with LeJOS 2 years ago I found it quite easy to get going using those pages.
Of course, all of these pages assume you understand how to write programs in Java - otherwise you'd need to look for a Java tutorial, like the ones published by Oracle at https://docs.oracle.com/javase/tutorial/.


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EV3 won't connect through bluetooth anymore
I was using VS2015 (C#) to write simple programs for my EV3 using a bluetooth connection.  This was working fine for several days and then suddenly stopped.  I can't for the life of me figure out why.  It's not my code, I don't think, because the sample program that came with the API also won't connect.  However, I can connect with LEGO LabVIEW just fine.
What I've tried:

Flashed the brick and updated firmware to 1.09H
Reinstalled BT devices and drivers on host PC
Reboots of brick and PC

I'm not receiving any exceptions on instantiating the brick, ConnectAsync(), nor any DirectCommand calls.  Connections with USB do work fine.
Any ideas?
EDIT:  I had typed firmware v1.06H (I believed this is what it was).  It's currently 1.09H, although I did manually update to 1.07H to no effect.

My son's new EV3 with 1.09H doesn't connect the official Android Programmer app, even though Android can see/pair the device. :( (They're not called Brick for nothing?)

You should always be using the latest firmware. If you have an EV3 brick that was produced in mid 2015 or later, it may have a newer Bluetooth chip that requires firmware v1.07 or higher. See https://bricks.stackexchange.com/a/7237/3498 for an unofficial firmware changelog.
If updating the firmware does not fix the problem then the name of the comm port probably changed. This is something like "COM1" or "COM5". Look in the Device Manager to see what comm port is assigned to your EV3 and make sure it matches your C# code.

Thanks for the answer, but unfortunately upgrading the firmware had no effect (see my edit).  Also, in case this helps anyone, if you attempt to connect to the wrong COM port an exception will be thrown.


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How can I make Custom Instructions for my MOC?
I'm a huge AFOL and recently have quit my job in order to take my part time job of selling Lego to the next level.
However, there's a new venture I'm having difficulty with and I would greatly appreciate if anyone has any advice for me...
** I have made a number of custom MOC's and my plan is to create instruction booklet's for the best ones and hopefully sell those online as well. I'm aware that Lego creator is available, however, I'm trying to construct a more tangible set of directions similar to the official Lego instruction booklets you'd receive with one of their sets.
I've seen similar custom directions (without any bricks included) on eBay and so basically I would like to know how that's made possible.
**Are there any businesses or individuals whom have the capability to create such instructions? Any representatives or recommendations you have for me would be great appreciated.
The Lego and AFOL community is amongst the nicest/helpful groups of people I've ever had the pleasure of being involved with, and I'm looking forwards to meeting even more of you this upcoming weekend at The Philly Brick Fest!!!!!!

I'm assuming you have looked at LDD and LIC from this question already? if so, could you specify exactly what you want that those are unable to provide?

To be honest, I am not very skilled when it comes to using LDD So I was hoping to possibly hire somone whom is much better than I am...also what is LIC? But before I do that, I wanted to see if it was possible to hire someone, send them my completed set, and then they would be able to create an actual Instruction booklet that is not a digital copy but rather an actual, tangeable, Paper instruction booklet much like that you might get from an official Lego set...my buyers have expressed they prefer the paper copy over a digital one.

If I were you I would change the title of this question to something indicative of your search for someone to do this work for you.
LIC is the Lego Instruction Creator - it's a tool some people use to make instructions.  I would say it's for "power users" though, so it may not be for you.

LIC is the Lego Instruction Creator

it's a tool some people use to make instructions.
I would say it's for "power users" though, so it may not be for you.

If I were you I might change the title of this question to something indicative of your search for someone to do this work for you.
As you are probably aware, there are Lego forums which are devoted to MOCs -- so I would solicit for some help there  (Try https://rebrickable.com/forum/ )

Film while you take it apart, then playback in reverse.

Have you tried this?  How did it work out?  When will you post it on youtube?

I never tried it myself, but I've seen vids. Looks kinda weird how parts fly into hands.

Google LDraw. It takes some knowledge to use it, but the LPub software that optionally comes with it can make custom instructions.
PS: I personaly recommend using MLCad.

I never made an instruction but to build some MOC's I have used the OpenSource Software Blender to create 3D-Models. There you can create the bricks needed and put them togehter in an easy way and render the images.

Are you still looking for lego instructions? I actually offer a service for this (through Fiverr), which I feel is quite affordable and rather professional.
Let me know if you are interested! I have 4 years experience with ldd and can help with that too.
Hopefully I can help you with that :)

Hi, and welcome to Bricks! As per our stance on self-promotion - it would be great if you felt able to register and not use a generic handle :) I believe you've been upfront about your affiliation here, so this shouldn't be considered outright spam.


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Printing an actual suit on a LEGO figure
I love LEGO bricks, and I'm always looking for more unique figs. I go on eBay all the time, and one person named onlinesailin makes AMAZINGLY detailed and cool guys. I want to know how to actually PRINT on costumes like the Joker's suit, or Batman's armored suit from Arkham Knight. What do I need? A certain printer or what? Thanks for answering guys!


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Interface between keyboard and NXT mindstorm
I want to make an NXT program that handles key presses from a user. First, I'd like a message to display asking the user to choose a key on the keyboard (S or M), and then depending on the chosen key some actions take place (e.g. starts counting the time). How can I do this? Do I need Bluetooth?

I think you should buy a Bluetooth Card for your PC to connect the NXT with your PC. After that you should program your Bluetooth Card to send specific Bluetooth Signal to the NXT while you are pressing a key. Next you should program your NXT to "react" to the specific signal sent from PC... That's all, it's not too easy...


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Multiple Powered Up trains on 1 Bluetooth controller?
My daughter got a Passenger Train for Christmas and I converted one of my old 9v trains to run using the powered up system. Is it possible to run the 2 trains independently or concurrently (preferably independently) on the one remote?
I’ve tried all sorts and have struggled to find anything that helps me.

Based on https://bricks.stackexchange.com/q/10486/6174 it seems like there is a 1:1 relationship unless you use some sort of proxy.

This is a video tutorial that describes how to control two motors or hubs with one controller. They are on the same channel so when the plus button is hit, both motors react to it and start rolling. This solution is useful when one needs two or more motors in a larger train.

Each train needs the following two components:

Hub
Train motor

I'll assume you purchased a second set of these to convert your 9V train with, since you're asking how to control both trains using the same remote.
The LEGO Powered Up team has provided an FAQ for Powered Up which contains instructions for how to pair multiple Powered Up Smarthubs with one remote, on either the same channel or different channels:

How can one single BT remote be used to control multiple receivers or switch among them? Will this be possible in the app?
You can link up to 5 devices (Smart Hubs or Smart Controllers) together.
To create a network you first need to connect a Samrt Hub [sic] and a Smart Controller.
First Hub connection
Turn Hub and Controller ON by pressing their green buttons and they will link. The LED will blink white and then shift to same channel color e.g. blue. You can now change the channel color by pressing the green button on the hub and toggle through the 5 channel colors. When turning OFF the Hub or Controller the last connection is remembered and re-established when turning both ON.
Adding Hub to network
With the first Hub and the Controller ON and connected you can add extra Hubs to the network by turning the new Hub ON and then press both green buttons simultaneously on the new Hub and one of the components in the network (Hub or Controller). The new Hub is now added to the network with the same channel color as the currently selected channel. Again toggle to another channel by pressing the green button on the Hub. When more Hubs on different channels are added to the network you toggle between the different channels by pressing the green button on the Controller.
Note: The current Powered UP app supports control of a single train.

Note that when you have two Smarthubs paired with the remote on the same channel, when you press a speed control button on the left side of the remote, both Smarthubs will respond. This is shown in a video by HispaBrick Magazine. This means you'll start both trains concurrently with a single button press. To avoid this:

Change the channel on one of the hubs by pressing the green button once. You can then switch to this channel on the remote by pressing the green button on the remote, and cycle through all 5 channels back to the other hub to control that other hub again.

Or if you want to be able to control each hub independently using each side of the remote without having to change channels on the controller, simply switch the plug on one of the hubs to the other port while both are still paired on the same channel.
The second port is typically used with a different device such as a Powered Up LED Light which you can install into your Passenger Train and you'd control the train motor and the LED light independently; however, it's not possible to have both motor and light controls and control two independent trains all on the same channel.

Ah, your answer is much better then mine! Upvoted. :)

Thanks very much for your detailed response. I have had continued problems linking the second train, it just continues flashing but I will reset everything and try again this evening following the above.

@Stereo: Let me know if it works out!

@LegoSonicBoy. I have tried to pair it as per the instructions (which incidentally is pretty much the way I had bee previously trying) and the second train/hub fails to join the network. The second hub when switched on flashes white but I cannot get it to then pair with either a hub or controller on the network.

@LegoSonicBoy. I have since followed the HispaBrick video you linked and have managed to link the 2 trains to one controller and all is working as desired! I have hunted youtube and failed miserably finding anything that worked for me so thanks for the link.

@Stereo: Glad you got it working! You can mark my answer as accepted by clicking the checkmark under the voting arrows. Oh and welcome to Bricks SE!

According to the LEGO Customer service website, you can control multiple train with the remote control, but not the app. Currently the Powered Up App only controls one Powered Up Hub at a time. Source: https://www.lego.com/en-MY/service/help-topics/digital/device-guides/powered-up/control-multiple
A more specific answer can be found in the LEGO City website: You can run up to 5 trains at the same time from one remote control. There are 5 channels on the remote control (you can tell them apart by their different colors) that can connect to up to 5 Smarthubs. Source: https://www.lego.com/en-us/themes/city/articles/question-06-028c2ae86b684ac78d5c7448e869c88a


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Are these old car models legit sets or MOCs?
Are these 4 historic car models legit sets or MOCs? If official sets do you know the set numbers?
How can I add more pictures then one?

These are indeed legit sets of the 70's.
390-2: 1913 Cadillac

391-1: 1926 Renault

395-1: 1909 Rolls-Royce

Only the red car in the top right looks like a MOC version of the red Cadillac  set


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What set do these large white pieces with Technic pins and an orange winch come from?
I found this at home with many other scattered parts and set, but I'm unsure what this one belongs to. What set is it from?

It looks like part of a Jack Stone 4618-1: Twin Rotor Cargo

Alexander O'Mara answered it quite well but if you are looking for instructions as well, then toysperiod have you covered.


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How to prevent discoloration or parts in storage?
I recently moved into a 1 bedroom apartment, and I am storing my Lego sets out in the living area. There is one problem: one wall is practically all window. Since it is unrealistic to have the blinds closed all of the time (since the lighting isn't great), and I don't have the space or money to buy display cabinets with the special glass that filters UV light, I installed UV film to the windows.
Will this be enough to save my Lego sets from suffering from discoloration, or should I be doing something else? This situation is only for a year or two, then I hope to buy a house where my sets can safely live in the basement, away from sunlight.

Product description says:

UV protection helps reduce fading on flooring, furniture, portraits, blinds and draperies

Reduce, not eliminate, because such film cannot remove 100% of UV, and regular light can also participate in fading a bit.
If you want to store them, not to display them, then box will do. One that isn't transparent. There are opinions that airtight boxes help, too, but I haven't tested that. Regular dark box did a pretty ok (not perfect) job for me when I stored my bricks for many years.

I want to have them on display, has anyone (Lego or someone independent of Lego) measured how long it takes before white starts to turn yellow/tan?  I have never had my bricks turn this color, but I have inherited some sets with white bricks that are so discolored they almost match the light tan bricks.

@Jedi_Maseter_Sam measurement is impossible - exact recipe for LEGO plastic was changed a few times, so any long term results had to be outdated. Modern recipe is supposed to be rather resistant to color changes. Also, it depends where on Earth you are, on what side are your windows, is ozone layer good where you live and so on.


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Black 2x4 curved top piece of assembly
This piece does not have an identification number on it. It appears to be part of a larger assembly. At each side are two 'legs', neither of which have stud receptacles, so it doesn't hook on to studs.
I'm guessing it slides down inside something as a top piece.
Can someone tell me what element it is?

Technically you don't ask what that element is, but I'm guessing that's what you want to know.
I think it is:
LegoFabuland Container, Side Bags / Saddlebags

ah true, I tagged it as piece-information and forgot the actual question


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How could I make a golf robot from a LEGO NXT kit?
I want to make a golf robot. It will be placed straight in line with the ball. It will approach the ball and swing.
The part where I get confused is how to get it to swing in a left-right motion when the motor attached is heading towards the ball.
I want to know how to build it!! I tried following some images I found online but there weren’t any details about the design.
This is what I would like to build. I'm curious about the motor and the golf swing part!

Welcome to Bricks.SE! Can you expand your question and show us what you have already tried? Right now your question is quite vague and likely to be closed for being too broad,

This model uses gears to do 2 things:

Change the direction of motion:

The motor turns an axle, on which a gear is attached (partially hidden black disk in the picture).
The first two gears shift the rotation out in front of the motor.
The next two knob wheel "gears" turn the rotation 90 degrees, resulting in the golf club motion you see in the picture.

Increase the speed of the golf club:
When you combine gears of different sizes you can change how fast or how strong the output is.
The first two gears have 36 teeth and 12 teeth, in that order. This makes the golf club move 3 times faster than the motor.
If you were to swap the gears, putting the small 12 before the 36, it would make the club 3 times slower than the motor.

You can find building instructions here. This model was designed to be built with the NXT Education Base Set. If you have the normal NXT retail set, you won't be able to follow the instructions exactly; there will be a few missing pieces, but it should still be pretty easy to find suitable replacement parts from what you have in the kit.

I’m new to this flatform so I am not sure if you’ll see this but.. Wow You really gave me a specific and amazing answer!! Thank you so much bless you!


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What is this short blade with a hole at one end?

What is this element ID?? Can you please help?

That's a 98347, a.k.a Wing 1 x 4 with Pin Hole


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Unknown Set: White spaceship? with clear blue canopy
Do you know which set this is? It's incomplete, and I would like to get the instructions. It looks a bit like a spaceship...

Hey Mc5,
Set #76028 Darkseid Invasion.
Build instructions here.

Have fun!

Awesome! Many thanks Rin Rio-Oki!


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Unknown sticker on a dark grey 1x2 tile, black lines, printed handled?
I bought a big bundle of LEGO, and I'm trying to find out the sets.
This one is on a dark grey 1x2 tile, with black lines and printed handled.
Can you identify this sticker?

Comes from Set #75038 Jedi Interceptor.

Many thanks! Unfortunately, I miss too many pieces. I'll move to something else.

That's cool.  Keep on asking.  That's why we're here;)


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Do you know which set these large grey ball and socket pieces belong to?
Does anyone know which set this piece belongs to:

The top two pieces there (not the 2x2 square) are
Cylinder Hemisphere 2 x 2 Ball Turret Socket Base

and
Cylinder Hemisphere 3 x 3 Ball Turret

The top appears in 28 sets, the simplest of which is this ion cannon


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Help identify this white and medium grey ship section
Can you help identify this ship section from a box of LEGO parts we have now?  It looks like it was in an epic battle.

Based on Engine 3X3X6 in white, this is from 7166-1: Imperial Shuttle

Or as Syberion mentioned it can also be
7264-1: Imperial Inspection

Which has almost the same build. The only difference I could find is the color of the 6 x 12 plates on the bottom of the build.

7166: Dark Gray Plate 6 x 12
7264: Dark Bluish Gray Plate 6 x 12

Based on the photo, I think its Dark Bluish Gary so it's 7264.
If you still have the minifigs for this set they will also tell you which set it is, as 7166 had the yellow faced figures and 7264 had the flesh tone figures.

It could also be from 7264-1: Imperial Inspection
they have the same build

Indeed I stopped looking when I found the first one at brickset.


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Which LEGO figure is this with white cape and red suit with a lightning bolt?
Could somebody please identify the minifigure in the picture please?

This is Shazam, a superhero from DC,

Paint seems a bit faded in your case, but this is the one.
This is a very rare minifig because it's a Comic-Con 2012 exclusive.
ID sh042 in Bricklink

As posted in the other answer, you have a knock-off version of sh042. Not worth much, if anything at all. Print on yours is all wonky, misaligned and definitely not something that would have passed LEGO’s QA stage.

Looks like the Comic-Con 2012 exclusive Shazam / Captain Marvel: https://www.bricklink.com/v2/catalog/catalogitem.page?M=sh042#T=I
From the quality of the lighting in the photo it's hard to be definitive but if I had to guess I'd say this isn't genuine Lego but a reproduction figure or knock-off (KO).

Thank you for your information. The lighting wasnt the greatest and picture was taken on older mobile phone , will try and poat a better quality photo now. Thanks again

Compared to the Bricklink photo, this opened mouth is skew. Also, the fabric of the cape is not LEGOlike at all. This is definitely not LEGO.


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Can you identify these (possibly) LEGO horses?
We got these old LEGO-compatible horses from the LEGO collection that used to belong to my wife's brothers (which means they are probably 20-30 years old). I'm wondering if they are genuine LEGO pieces.
If not, I wonder what brand are they.
Either way, I wonder which set, if any, they belonged to.

I think there was another black horse, which I couldn't find, and some or all of them also had a brown saddle part.
EDIT:
I managed to take a good photo of the stamp on the black horse, so it's definitely genuine LEGO.

Those horses look like legit LEGO-brand horses.
Specifically:
White Horse with Black Eyes, White Pupils and Dark Orange Bridle Pattern: 4493c01pb04

Black Horse with Black Eyes Circled with White, Brown Bridle Pattern: 4493c01pb02

In order to be extra sure they are genuine LEGO, look for the "LEGO" stamp on the inside of the hollow studs on their back where the saddle goes (it's a little hard to see).
These horses each came in a fair number of sets. Check the BrickLink links for a list of possible sets. If you are sure they both came in the same set, these are the sets both came in:

5394-1
6021-1
6042-1
6055-1
6073-1
6074-1
6080-1
6081-1
6085-1
6086-1
6090-1
6095-1
6419-1
6761-1
6762-1
6769-1
8777-1
10039-1
10176-1

Now that you mentioned it, there is some stamp on the inside of the hollow studs. I didn't notice it earlier. It could be LEGO, though it's hard to read properly.

It was already identified, but just to mention, recently there was a set (10676) that contains the white horse. I can confirm because I have it. Also, when I was a kid I had a set that had the black horse (now lost because I was a dumb kid)

@Moacir: 10676 has a different white horse (10352c01pb04).

@kundor Oh, sorry. It is a similar piece but not the one OP asked for. Thanks for the correction

They are:
LEGO Animal Minifigure - WHITE HORSE

and
Horse (Black) - LEGO Animal Minifigure

But if it does not have the logo or part ID then it must be a copycat.
Refer this post for real LEGO identification help:
General guidelines to identify real Lego pieces from fake or copy?

I owned these two medieval castle sets as a child. Both came with different coloured horses (white, brown and black).
There are also a number of knight sets containing horses, for example this one.

Since you are asking for a set too,
I remember playing with this sort of horse long ago.
Mine was the horse of a knight, like in this set.


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My 8880 Super Car: Quality criteria for potential buyers?
A couple of years ago I bought a used 8880 Super Car for around 50 Euros. I thought it was an exceptional bargain but now I am not so sure any more. I want to sell the set and want to avoid a disappointed buyer. The picture below shows the most obvious show-stoppers: stickers, prints and yellowing of the wheels. The stickers are more or less OK, headlight prints are very good. The round plate is only a "reference white" for comparison. There is some yellowing on the wheels, but it is moderate, same for the gear plate.
My question is: What else would you as potential buyers of this set consider important, before bidding?

First of all, let me congratulate you, that was indeed an amazing deal you made back then. This 8880 seems to be near mint condition, and should fetch you a nice return should you choose to sell it.
Speaking both as an experienced buyer of used LEGO sets as well as an owner of an used 8880, my personal priority list of criteria is the following:

Completeness: are all pieces present, are they the correct ones (color, part design, prints, stickers)?
Physical state of the pieces: are the rubber parts cracked or still flexible, do the bricks have scratches, teeth marks, scribbles, or ...gasp... maybe even glue on them?
State of the prints: were they preserved in a good condition, or have they chipped, faded, discolored, etc?
State of the stickers: are they even applied at all or still on the sticker sheet, if applied then how precisely, did they fade, discolor, crack or chip?

For STOMPs (STicker Over Multiple Pieces): were they applied correctly, were any torn or were they cut neatly, is there maybe dirt or dust on the strip of sticker exposed between two pieces?

Instruction sheet(s): are they present, in what condition: earmarks, tears, binding, have they been doodled upon, have they faded or discolored?
Box: Is it present, does it show any damage due to storage, water, mold, shipping, was it opened carefully or torn open?
(Disclaimer: This criteria is actually a lot more important than many above but it can almost never be known or judged before buying.)
Shipping: Does the set ship with adequate packaging that ensures no pieces get lost in transit (I have received boxes that had holes in them large enough for smaller pieces to fall through), does the seller use appropriate amounts of packaging material to ensure the pieces don't get scratched up too much during transit?

Note again, these are MY PERSONAL priorities, and thus reflect my attitude which priorizes function over looks, over collectability. Other possible buyers might not care for the exact design of a half-bush or the correct generation of a 8T gear, but might place more emphasis on the stickers or the box for example.

Thank you for the assessment. Are you aware of any parts that need special attention in this set? Apart from some dust I didn't see any damaged parts in my set. I don't have a box, but the instructions are in good (not perfect) condition.

There are a few pieces unique to this set: on your picture I can see the transmission cover and handle, wheel rims, the white steering arms and the grey connector pieces. The blue wishbone pieces for the suspension are also quite rare and prone to breaking (IIRC). Your best bet would be to take the inventory of this set from a trusted source (Bricklink, Brickset, etc) and check the part IDs along with the count of each type of piece. This way you can be 100% sure your set is complete, the rest can be photographed to show the general quality. If a buyer is picky about something, they would ask.

Besides the obvious quality checks, something that is quite important to me when buying second hand: in what state of assembly will the set be shipped?
Unless it's a set I'm desperately searching, I will almost certainly forego bidding if the set appears to be shipped entirely assembled.
Partially disassembled is even worse in my opinion.
Also not acceptable is the set entirely disassembled but all pieces thrown together, I believe this causes scratches on the pieces and makes it easy to have pieces missing (with the mistake possibly happening on my end while resorting the pieces).
Ideally the set is shipped entirely disassembled and the pieces sorted in zip-lock bags in a logical way: large pieces with large pieces, smaller with smaller... In such a manner that it's easy to check for completeness and I'll have fun rebuilding the set.
Problem is that the shipping manner is seldom described in any online advertisement, one needs to ask for this...

Michael, this is a good general comment on selling LEGO. Care about wrapping/boxing AND advertise it.


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Please identify this black 2x2 tile with sticker, sunset with 2 palm trees and boat
Can someone identify the set origin of this sticker on a black 2x2 tile?

This is part #  3068bpb0183 : Tile 2 x 2 with Hovercraft Sunset Pattern (Sticker)
From 8485-1: Control Centre II


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Can I still motorize Universal Building Set 8034 and other from that time with modern elements?
Set 8034 was supposed to be motorized using 8700. Of course,  this is way outdated and kinda pointless to buy motor this old.

Current set for this purpose is 8293. Problem is, old motor was 5 studs long, new one is 6, and new set does not provide rubber band for power transmission. Can these be easily fixed? And is there anything else I  should be aware of?

The length of the wire is another thing to be aware of. The wire attached to the motor in 8293 is only slightly more than 20 centimeters (might be a few centimeters more, I don't remember), you can double that by putting in the switch which has about the same length of wire, but it's still not much. I don't know how long the wire in 8700 was, but it looks longer.
You should also be aware that the new motor doesn't have a pin sticking out that rotates, but a pinhole, if you put in a 2L axle it will look about the same, but the notches on the newer (part 32062 - the older part 3704 didn't have notches) are in a different position (I believe they are in the middle of "each L", while the pictures show that the notch on the axle extending from the old motor is in the middle of the "half L" closest to the motor, the belt wheel was about ½L thick), so you'll have to think about how you place the belt wheel if you want to use a rubber band directly from the axle to transfer the motion. You can work around that with a (half)bush on the axle, but that significantly changes the circumference the rubber band goes around, as thus the gearing. (This section was significantly extended to address Michael Verschaeve comments, thanks goes to him for pointing out the issues I believe I have now addressed)
I don't know set 8034, but from the pictures it looks like it would be hard to fit the new motor due to the increased length.

I'll wait with accepting 'till I'll have a chance to assembly this car again, but I'm afraid you may be right that cable length and motor length will make it fail. Also, good catch about notches on 32062 - I didn't even thought about that to be an issue

If the notches indeed do not align, easily adressed by putting a bush or halfbush on the 2L axle ...

Also, I doubt I have ever seen the notches in a 2L axle being used as a pulley for a rubber belt, I kind of doubt they are deep and wide enough...

I have extended the answer (the middle paragraph) to address those issues. (It became a rather long comment and felt like something that belonged in the answer).

8700 came with two wires.  The short one was about 20 cm (suitable for adding a battery trailer to your self-powered vehicle), while the long one was 75 cm (suitable for a remote control).

Agreed with the issue of the notch in the 2bar, a better option might be the technic smooth half-bush?


text:
How to use the direct command to make EV3 motor backward?
I write the java language. I use ev3 direct command make ev3 motor to run,
example:
"opOUTPUT_POWER,LC0(0),LC0(0x01),LC0(20), opOUTPUT_START,LC0(0),LC0(0x01)"

In this case, the power is 20 so I write value (byte)0x14 resulted ev3 forward.
When I want to make the ev3 backward, how can I do??
I think change power 20 to -20, but I don't know -20 hex value.

The LC0() macro treats the value as a signed 6-bit integer.
From bytecodes.h...
#define PRIMPAR_CONST_SIGN 0x20
#define PRIMPAR_VALUE 0x3F

PRIMPAR_VALUE is where the 6 bits come from. PRIMPAR_CONST_SIGN means that the 6th bit is the sign. This means it has a range of -32 to 31, inclusive.
We must also keep in mind that computers use the 2's complement for negative integer values, so we can't just use 0x34 (0x20 | 0x14) and expect it to be -20.
0x20 will be -32, which is the lowest number possible. So, to get -20, we would need -32 + 12 = -20. In 6-bit hex 0x20 + 0x0c = 0x2c. But, you don't actually have to use hex formatted number. We can let the compiler figure it out like this: (-20 & PRIMPAR_VALUE). This trims the number -20 down to 6 bits. In fact, this is what the LC0() macro does internally, so we can just write LC0(-20).
If you need values larger than this range (e.g. -100 to 100), then you need to use the LC1() macro, which uses 8-bit signed integers. It has a range of -128 to 127. So, this will work too: LC1(-20).


text:
Is the LEGO Space theme discontinued?
I really liked Space when I was a kid. And now is the time when my friends have kids old enough to play, and I'm old enough to admit I like to play. But I can't see any space sets except realistic City ones, and Star Wars.
Is there any official or trustworthy unofficial source that says if Lego own Space series are officially over, or will reappear in future? Note, I'm not asking you to guess, I'm asking about possibly existing sources.

At this time, there has been no announcement of a scheduled unlicensed LEGO Space theme. LEGO is not going to make an announcement that "We forever and ever retired LEGO Space, and it will never-ever come back." It's just not going to happen. In addition, they don't reveal what they are working on, until it is time for an official announcement - usually about six months or less before release.
However, there is no need to wait and hope that LEGO Space will come back soon. You can still buy all the previously released LEGO Space sets on the secondary market like eBay and BrickLink. You can buy them brand new in the box, or used, or anything in between. Many of the sets sell for very reasonable prices - especially those from recently retired LEGO Space themes like Alien Conquest, Galaxy Squad, Space Police, etc. I would suggest first checking the BrickLink Catalog to familiarize yourself with all the unlicensed LEGO Space sets ever released on this page.
Also check the going prices for the sets you would like both in new and used condition (all of this is listed in the BrickLink Catalog). Besides buying individual sets on eBay or BrickLink, once you get a sense of what LEGO Space themes you would like to focus on, you can also check on eBay for bulk lots. These will likely be in used condition, and there may be some parts missing, so make sure you read the description carefully. Bulk lots can be great starters for a kid's collection.

I  mostly agree, but for example Miners could be considered discontinued when their specific website went down. Sometimes there is something  that is a pretty official sign.

Are you talking about LEGO's webpages for different themes? Those constantly change and come and go. They only keep the ones up and running that currently have products available. For example, the Harry Potter and Jurassic World micro-sites were taken down when the previous products ran their course, but now that new sets are coming the sites will be up again. There has never been a generic Space section on LEGO's website. The specific sub-themes had their own pages with no overarching umbrella theme. Space is not like LEGO City, where the same sub-themes are rotated over and over again.

Although the stand-alone, unlicensed Space theme technically remains discontinued, LEGO has recently released an unlicensed Space sub-theme under their City theme.
While these builds seem to be more "near future" than the classic Space sets, they can be whatever you want them to be. This is LEGO we are talking about, use your imagination to figure out how these sets might link in with classic Space sets or factions or even licensed themes.
For example, you could have the Mars Research Shuttle below land on Titan, where it encounters a legion of Blacktron Battraxes (Battraces?) led by General Sweet Mayhem and must call for help from Iron Man, who arrives in a TIE fighter.

According to this advert Lego are running on Facebook they are still making "Lego Space" so it can't be discontinued.


text:
Are there any wheels or rings that fit in pin clips?
I was experimenting with Lego part 16091 Vehicle Steering Wheel Small and various clips, mainly the ones that fit onto bars. To my frustration I found that the clips do not engage at all with the ring that forms the wheel’s circumference; they fall right off.
So my question is this: are there any similar parts (wheels, rings) that do engage with clips in this way?

I feel the following part https://www.bricklink.com/v2/catalog/catalogitem.page?P=30033#T=S&O={"iconly":0} is relevant here

The small Technic Steering Wheel and what I think is this rubber belt connect to clips: