text:
myblock for a proportional gyro turn that randomly fails when in a larger program
I have a proportional gyro turn myblock that fails when played in a longer program.  The myblock works perfectly fine when played by itself.  The most confusing thing is that the way it fails seems to be random.  Sometimes you play the program and the turn is too far, sometimes it doesn't turn enough and sometimes it works as expected.  We have had similar problems before with other complex myblocks that seem to misbehave when run in as part of a long program but work fine when run by themselves.
I'm not sure the best way to attach code, so I've linked it to the file here.
https://drive.google.com/file/d/0B9eJwUXdFba-T3k0cTdYNTJ0eWc/view?usp=sharing

When you run the program do you reset your bot at the right position?

I'm not sure I understand what that means.  Do you have an example of where and what I should do?

I've looked at the file, and I don't understand what it's supposed to do. First you have some program called "ManFlower". It includes a bunch of MyBlocks that we are unable to decode, and since you're not showing what they do we can't solve the problem. Then you have another program called "SuperGyroTurn" and it is too confusing and hard to see what your code is doing, without details or at least a detailed walkthrough of the program we won't be able to solve this, so we may have to close your question. Another necessary piece of info required is how the robot moves which is not specified.


text:
How to load an RCX from a modern system?
I recently bought a new in box 1.5 Mindstorms kit featuring the RCX. My computer unfortunately does not have a 9-pin connection, and the software does not appear to work on Windows 10. Short of buying an old computer, what can I do to still load programs onto the RCX?

Buy a USB to Serial adapter. There are USB IR Towers, but the drivers are only for older version of Windows. A new USB/Serial adapter, on the other hand, should be compatible with Windows 10 (Windows 10 requires signed drivers, so do your homework before buying).
Use 3rd party software. For example, Brickx Command Center and leJOS are compatible with RCX and have a better chance of running on Windows 10 than the official LEGO software for RCX.

I also found this site, which has the same advice, but with pretty pictures and more details: http://www.instructables.com/id/Making-Mindstorms-RCX-Work-Again/
Note: If you use Linux, there is a built-in driver for the USB IR Tower in the kernel, so just about any Linux desktop system will "just work".

Will the 3rd party software work on a 64-bit machine?

I suspect most of it will. I've only used BrickxCC myself.

Honestly... it was WAY easier for us to find a computer on eBay! We bought an IBM ThinkPad with Windows 2000 installed on it.  We won the auction with a bid of $28 and with shipping it was the best $40 I've spent on eBay!  The laptop fired right up, we inserted the Lego Mindstorms Robotics Invention System disc, and voila!  It installed quickly and easily.  The USB tower was recognized right away and my son was programming his RCX 2.0 within 15 minutes of opening the eBay package!  We have the Mars expansion set and the RoboSports set also.  We are BIG fans of the 20 year old RCX systems!

While this doesn't directly answer the question, I think it's a useful idea. Thanks for your contribution!

Not easy to find space for, but nice idea.

There are a few hurdles to jump through.
For the IR tower, you need one of the following:

Infrared Transmitter with USB Cable (cheaper BrickLink listings on the part page) (uses USB instead of 9-pin).
A USB-to-9-pin adapter with a compatible driver (might be hard to find at this point?).

A 32-bit system to run the software on. If you don't have such a system, one option is to install an old 32-bit version of Windows in a virtual machine, and pass the USB device through to the VM.

The USB RCX Tower only has 32-bit support, which doesn't work on modern Windows versions. It has been reported to work on Linux though (I didn't try that myself).
I own a serial USB RCX Tower which I connected to my computer USB (modern Windows 10) using a (modern) LogiLink AU0002E RS232 adapter which has a Windows 10-compatible 64-bit driver.
I use leJOS and because it is Java I have IntelliJ IDEA community edition as programming environment. This doesn't work with Java 5 and older versions. IntelliJ IDEA does however still support Apache Ant 1.9.14 which in turn supports Java 5 and newer.
Java 5 is the maximum version for leJOS and the minimum version voor Apache Ant 1.9.14 so Java 5 is just right. An Ant build script can compile the java source code and send it directly to the RCX, all from the programming environment.
I started documenting everything here: https://github.com/oversticht/lego-rcx-lejos/blob/master/README.md

source: Stack Exchange

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

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

sort: votes


text:
Can you identify this old set with LEGOLAND minifigs?
There is nothing written on the box and no LEGO logo anywhere. All the pieces that come with it are LEGO.

It is one box from 364-1: Harbour Scene from 1975:

Here's what the particular box looked like in newer condition:

And here's the set freshly opened with your box slotted into its place. Your box is the top center one if you can't tell from the image.

Here's a video covering this set in detail.

Yep.... but it came inside the larger box? Was a separate item?

@MiguelRicardo Do you just have the cars? If so, maybe the cars where in a separate box inside the larger box.

Nice work. This is definitely one of the boxes from 364. I've edited this answer to reflect that.

Ty all, thats it, and probably have the complete set in pieces from what i can see (no outside box or intrstucions thou...) many thanks again

@MiguelRicardo Great! The instructions are available here if you're trying to put it together: http://peeron.com/cgi-bin/invcgis/scans/364-1/

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


text:
Lego Racers in Special Box
I am trying to collect all of the Lego Racers sets in the unique box design that set 8121, 8120, 8119, and 8122 have. Does anyone know if those are the only four in that box design? Thanks.

Set 8121, 8120, 8119, and 8122 are the only ones with a red box.

It also comes in black

See this link for a complete list of boxes
Catalog : Original Boxes: Racers: Tiny Turbos


text:
What LEGO set is this? White pieces, brick separator, and blue pilot Clone Trooper?
I can't identify this.  What does this build?

The minifigure  is  501st Clone Pilot (75004)
So it should be this set
Z-95 Headhunter

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


text:
What is the best way to buy bulk bricks ONLY?
I've been finding that most bulk lots on eBay and the like tend to be mixed LEGO. I'd really like to buy lots with bricks (2x2, 2x4 preferrably) ONLY. Where can I look, what search terms can I use, and what strategies can I employ to get the best deals?

Have you checked out a Lego re-seller like Bricks and Minifigs?


text:
Technic Firetruck 8289 with different wheels?
I am a bit confused with the Technic firetruck set 8289. The photo on its box:

clearly shows it has the wheels 56145c02:

however, according to this photo from BrickLink

it has 6595c01:

In the parts inventory both wheels are listed, but the parts of 56145c02 are also shown as alternate parts.
My questions: Does this set have a "facelifted" variant? Is there an alternate box showing the set with the other wheels, or LEGO simply changed the content without changing the box?

Interesting! I think I spy another difference between the two photos: The cabinet door on the side — in front of the rear wheel — appears to a have different labeling scheme. And, if I squint hard at the low-res photos, I may be able to detect differences in the license plate number. Wondering if anyone else can verify these diffs or can see others.

I think the license plates are the same, however the sticker below the windscreen is different - in the box art and on the sticker sheets on BrickLink it's "Truck 4", while in the other photo it's "Fire and Rescue". That might make the lower photo a development "product shot" taken before the wheels and stickers were finalised?

The instructions show and Brickset lists 4496197: Rim Wide W.Cross 30/20 as the wheel rim of choice, which fits with the release year of the Fire Truck (2006) and the manufacturing dates of the rims (2006-2013).
BrickLink's "preferred" rim was only manufactured up to 2006, which might explain why it lists the pictured rim as an Alternative part - as that would have been included in later runs of the set.


text:
Identify LEGO set with black door, large sand arch, dark-sand bricks, and tan plates?
What does this build? It has a black door, large sand arch, dark-sand bricks, and tan plates.

THese parts come from 10232 Palace Cinema, based on the black door and the two 8x8 wedge plates in Tan.


text:
Two Mindstorms touch sensors: how to determine which sensor was pressed?

I'm trying do make simple program. Two motors, two touch sensors. Sensor one increases speed, sensor two decreases.
The whole program works very well but only with one sensor. When I put some logic that has "Wait for sensor two" brick it just fools around.
The algorithm is very simple:

Variable i - counts times sensors being pressed
Variable Znak (eng. sign) causes variable i to decrease if negative or increase if positive.
Motor speed is calculated by multiplying i by 10.

How can I solve this kind of problem?

I found an answer. I read in a book that I can't fork in a loop. But I can do up to 4 separate threads. So I did 3 threads:

Running/changing motors speed based on a variable "i" which is changed in other threads.
Waiting for a touch sensor A being bumped and increasing var "i".
Waiting for a touch sensor B being bumped and decreasing var "i".


text:
What is the largest jump in LEGO instructions?
What is the largest gap in LEGO instructions in terms of build time needed to complete a step? For example, Skyline (5526) includes this step:

That is quite a leap between steps 14 and 15. I'm curious to know if any sets leave more up to the builder than this.
I saw this over on Reddit and thought it might be interesting to get answers over here.

Urgh, that set + instructions looks like a nightmare build.

Set 8880 - Super Car Although the parts per instruction have a relatively small number, it can take a long time working out what part out of the list goes where.  It turns into a prolonged "spot-the-difference" contest with the previous page to get anywhere.

I haven't looked at the 10214 London Tower Bridge instructions, but those maybe leave out many steps describing the second tower. To some degree I noticed this in the instructions for the 70618 Destiny's Bounty when it comes to the second railing which is a mirrored version of the first one.

@Aziraphale Most of 10214 is actually (x2) instructions :)

It's difficult to judge build time, would you consider steps that include many bricks to have a long build time?

Would you consider step 18 in this set to be a single step?

@Ambo100 I think so. This makes me want to pick up some Model Team sets. :) Those were really nice.

@Ambo100 Is that sub-steps within a sub-step? We need to go deeper!

Car Chassis 8860 gets my vote for complexity of a single step.

The instructions are laid out so that you have two pages like this on top of each other.  I was building this model with my 11 year old son recently, and at almost every step on the last couple of pages we found we had missed something from the previous step.


text:
Did any sets have lots of 1x2 smooth tiles with gauges on them?

1x2 smooth tile with red 82 and yellow and white gauges pattern
I've inherited some LEGO and strangely it has 28 pieces of the above tile. Is there a set that uses a lot of these tiles?
I can't seem to find anything with more than 1 or 2 of them used.

The link you provided would be enough for me to consider it an authoritative answer.  They could have bought them from the wall of random bricks from a LEGO store or gotten a batch from BrickLink or a vendor at a LEGO convention.

Not sure how I managed to add that link - I thought I'd just copied the description that was with the picture I found on the net!

I will wade through the list that the link provided,  the lot I have seems to be lots of bits of incomplete sets so I'm trying to unravel each mystery. I'm inclined to think the 28 pieces are part of a set, as most of the other bits seem to form sets. But you could be right, might be a random lot. I just hoped someone would recognise such a large number of those pieces as conspicuously part of a certain set. Thanks for your comments anyway

@David C; I have edited your question and added the link

No. :)
I checked several "gauges pattern" tiles. There is no set with more than 3 of them.


text:
Can't create block: "Use of a block which no longer exists"

Unable to compile some documents for deployment:
Program.ev3p: Use of a block which no longer exists.
PutInRange.ev3p

The block I want to make. It will put a input value inside a given range.
When I try to upload i always get a error. I already deleted every thing and started new. And always it will give me a error. The Lego software looks very buggy to me. Am I the only one that has these problems ?

This is the MinValue block that gives the minimal value of two.

This is the MaxValue block that gives the maximal value of two.

And this are the blocks in my program, and there all there.

Can you upload the project so I can test it by myself? I've heard the error message before but I'm not quite sure what the solution was. Maybe if I can test with it there's a chance I remember the solution.

Try exporting(saving locally) the block that shows error. Then delete it from the program and import it from where you saved it


text:
Can anyone identify these 1x1 round tapered pieces?
Can anyone identify these pieces?

Source: http://bsg.deckdesigns.de/minis/raptor/raptor.htm

Source: http://www.moc-pages.com/moc.php/26424

The first piece is 424 Technic Hub / Handle 1 x 1:

It's actually pretty rare, only appearing in 9 sets from 1995-2006, and likely to stay that way as it has a similar newer counterpart, 18654 Technic, Pin Connector Round 1L which probably replaces it.
I cannot identify what those bottom black inverted slopes are though. It looks kinda like Wedge 6 x 4 Triple Inverted Curved, but without the middle 2 studs up front.

Thanks, that's the first one (never would have found that I guess). Got any Ideas for the second? There are some more images at the source, but all somewhat blurry. Looks like this one, but with inverted roof at the sides:
(https://i.imgur.com/ruy9ZMm.gif)

@Christian Sorry, I missed that image. I can't identify it either, I've never seen a piece exactly like that.


text:
What are these 1x2 clip and bar pieces?
I am not sure what this piece is and I need to know what it's called so I can find it on BrickLink.

Those pieces are:
Plate, Modified 1 x 2 with Handle on Side - Free Ends

And
Plate, Modified 1 x 2 with Clip Horizontal on End


text:
Help identifying unusual Technic part, long beam with 4 studs on end
I have a large collection of parts and I came across this slightly chewed, possibly Technic, part. No numbers on it, just the Lego on the studs. It's 15 Technic holes and then a T-piece on the end with 2 studs either side. The head seems to have a slot through it. Any ideas?

It looks like your questions was answered. Don't forget to mark the best answer if you feel it is correct.

That’s a crane-arm centre. It’s usually used in non-Technic sets together with the crane-arm outside to obtain a telescopic arm, e.g., for cranes or firefighter ladder trucks. The slit at the end is to insert a piece of string for using it as a cable crane.
Here's a picture showing this piece in use as the boom of a crane from 4552:

Great! Thanks very much. I shall see if I have the rest of it lurking in my pile of bits


text:
Why do sellers do lots of 'random' bricks?
I've often seen sellers of large lots split them up into (usually 100) piles of 'random' bricks to be sold that way - even if they got the lot in a more organised manner.
To me, personally, randomised lots like these are entirely unattractive and feel a bit deceptive (as pictures included usually depict the WHOLE lot).
What is the buyers/sellers incentive to sell LEGOs like this?

I have seen those lots on flee markets, in bags. Maybe the seller has them already in the bags and tries Ebay first.

I think their rationale is simple: selling 10 smaller lots is bringing them more money than selling it all in one big lot. It might also be a way to mask the fact that there are very few good/interesting pieces in the lot; by splitting it up but using the full lot picture every purchaser hopes they might get the good pieces. Finally, there could be some deception going on ... if you see a picture with a lot of run-of-the-mill parts and some rare/expensive ones, and you buy the whole lot, you expect to get those pieces. If you buy a part of the lot, you have no way to validate that those special pieces were ever included (they could have gone to one of the other purchasers, or, and this is where the deception comes in, they might have never been included).
Edit: there might also be a more practical reason: cutting the lot up into certain sizes might allow the seller to ship using a favorable shipping rate (e.g. First Class Package in the US) versus a more expensive shipping method for the entire lot.

Does it bring in more money, though? I find it hard to believe people wouldn't pay more for guaranteed pieces than what effectively amounts to a blind bag.

Depends. At a rate of $5-$10 per lbs a large lot (let's say 20lbs) would cost $100-$200. That's a big chunk of change for "just some pieces". If you split it up into 10 2lbs lots, you can charge $15-$25 per lot and sell those easily. Much more manageable, and likely cheaper for the buyer than buying a generic brick box from LEGO directly.


text:
Can you identify this LEGO board game with square paper tokens?
I have some of these cards which I found at the bottom of an old box of mixed LEGO and I am trying to identify them.
I think they came from a game maybe?
I used to get the Bricks n Pieces magazine, but not sure if they are from that. I would guess they are from the 1990's.
Each card is approx 1cm square...
I vaguely remember playing with them, but can't identify what they are from - nor can Lego themselves. These four are all I have left.
Can anyone help?

The 2 sets pictured are 6811-1: Pulsar Charger from 1990 and 6988-1: Alpha Centauri Outpost from 1991. That may offer a clue to how old it is.

thanks for identifying the sets and years. It might help narrow it down a bit... I'm still none the wiser yet though...

found it at last...!
They are cards from this game from the 1990s
Space Police / Blacktron II / M:Tron Poster Game
https://www.bricklink.com/v2/catalog/catalogitem.page?G=921800

Nice work! I'm glad that you figured it out!


text:
What part in LEGO digital designer can be used for a tank track?
I'm using LEGO digital designer to model a LEGO tank. I don't seem to find parts that can be used to make the tank track and the inside wheels; I found a "caterpillar belt" but no wheels that can fit inside the track.
There is a part called "caterpillar track", and unlike the belt the track requires wheels of different diameter to fit inside it. Again, I can see the wheel for the wider end of the track but not the narrower end.
Are there any parts that can be used for tank tracks at all? Or should I look for an alternative solution?

Make sure you are using LDD extended since the other modes don't show all the pieces that exist. In LDD extended you see every lego piece you could.

The caterpillar track and belt are both fixed length pieces.
I would recommend the more versatile #57518 'Technic, Link Tread Wide with Two Pin Holes'. The part can be used to make a track as long as long as you like.

The tread is compatible with:

#57519 - Technic Tread Sprocket Wheel Large
#57520 -  Technic Tread Sprocket Wheel Small


text:
EV3 brick Bluetooth connection error
I’m unable to pair the ev3 brick to our iPad mini. Both see each other but I keep getting this error on the ipad, Connection Unsuccessful, make sure ev3 is turned on and in range. And the ev3 shows a screen...
WiFi I turned off on both and on the ev3 Bluetooth is turned on along with visibility. I’ve played around with checking and unchecking iPod/iPad/ etc box.
They paired before but we were experiencing inconsistencies with the brick while running programs and it was advised to try updating the brick so I did and now they are not pairing.
What should I do?

I was experiencing similar problem with my Windows PC and EV3 brick.
Restart bluetooth on both, PC/Mac and EV3.
Do NOT pair from the brick.
Begin pairing from the EV3 Mindstorm App on your PC/Mac.
It should pair and work as expected.

This answer does not help. I upgraded and downgraded my firmware, tried, ipad toggle, restarted, it shows the wifi symbol but shows NONE in connections

I tried with Bluetooth. Haven't used wifi so can't comment

Pairing from the device helps. If you paired before, remove the bluetooth pairing.

Wireless connection on the EV3 is such garbage, this morning it took me over half an hour to pair the thing with both wi-fi and bluetooth to no avail. In fact, it was so hard that I received all sorts of error variations, to the point where the brick CRASHED when searching networks for the fifth time. I needed wireless because it was too hard to stick the big wire into the brick which was barricaded by other mechanisms, but after all the work I just wished I didn't do it in the first place. No, seriously, never use wireless. If the first try doesn't work then don't even bother fixing it.

I'm experiencing this kind of problem a lot recently.
What helps me when I'm completely stuck: Re-Install the newest firmware (1.09H/E/D).
After this update restart the EV3, close all Apps (shut them down, not switching to Home) and try the connection again.
This helps me in most cases.

I was running into a similar issue - iPad and EV3 could see each other, but got the "Connection unsuccessful..." error message.
The EV3 and iPad had paired previously, and then I updated the EV3 firmware.  To resolve the issue, I went to the iPad's Settings->Bluetooth and found the EV3 brick listed.
I clicked on the information icon (blue i in a circle) and chose "Forget This Device".  I was able to then repair from inside the EV3 app.


text:
Different surface roughness of tiles. Quality issue?
Recently, I filled a PAB cup in the nearest LEGO store. Among other parts, I also took a lot of light bluish grey 2x2 tiles. The following image shows some of these:

However, reflected light reveals that the surface of the tiles can be quite different. This image (same parts as above) shows that there are obviously two types of tiles. One with a really smooth surface, with the stud ring on the underside visible from above. And one with a rough surface similar to brushed metal:

I am a bit surprised to see LEGO products with their sub-micrometer precision molds showing such behaviour. Are different production lines mixing here? Have you experienced other parts with different properties that should be the same?
Update:
Alexander O'Mara suggested to examine the underside, and indeed there are some patterns. First, the smooth tiles:

Now the "brushed" tiles:

You notice the groove above the word LEGO on the smooth tiles that the brushed tiles don't have. The number 3068 is of course the same on both. There is a lot number (?) in the format XX-YY with YY being underlined.
The smooth tiles all have XX-57 with varying XX (right hand side), the brushed tiles all have XX-49 with varying XX (lower side, next to the "3068").
So, what does that mean?
EDIT:
One observation: inside the bottom tube, the surface shows a structure in the smooth tiles, but no structure in the "brushed" tiles. This could mean that the 3068 tile consists of two pieces that are hot-glued together in the process: One part covering the upper surface and sides, and another piece with the bottom tube and inside. The upper, covering part (from which small pieces are stamped out) may itself have an upper and lower side with slightly differing roughness. Maybe the production process doesn't prefer which side is up, so sometimes a rough side can be seen, and sometimes not. This is only a theory.
Can someone point towards an answer?

Do the undersides between them distinguishable at all? I wonder if there are different versions of the mold.

Good point. I will have a closer look and update the question today.

The XX-XX numbers I believe identify the mold that made the piece (so if they get defective ones, they know which mold has a problem). Possibly The second half of the number identifies a version of the mold? I wonder if perhaps one version is/was used for painted or sticker pieces (I know it seems weird to have a different piece for stickers, but I've seen them provide smoother roof tiles for stickers, sometimes with a mix in the same set).

Do you mean slope bricks or tiles that are used on roofs?

I mean the sloped bricks.

That is indeed interesting, because most of the slopes with stickers have the usual grainy surface of slope bricks. Do you mean that there are e.g. 45 2x2 slope bricks with a smooth surface?

Not entirely smooth, just about half the texture of the regular roof tiles (unless all roof tiles are like that now, I'm not sure). I remember the Dino Attack Iron Predator having 4 2x2x3 slopes, 2 with less texture, to which the stickers would stick better (the other 2 did not get stickers), though the instructions did not mention it.

Interesting. I looked at my sorted Tile 2x2 in light bluish gray and all have smooth tops. Mold numbers are XX-47 (without slot above logo) and XX-53 (with slot above logo).

From TLG Customer Service (emphasis added by me for one possible explanation):

I truly appreciate that you sent this to us so that we could see the variation
  in the parts. Being able to see the numbers on the inside was very
  helpful!
We haven't had any reports about quality issues with this element for
  any of the pressings. I've actually taken the link you provided and,
  as you know, the LEGO® Quality Team takes the quality of our products
  very seriously, and our team will now be able to look at these images
  in the post and make further evaluations. It could be that the mould
  was changed and the new mould hasn't worn smooth yet but I can't say
  for certain that that would be the cause of the variation in the
  texture on the top of the tile.
Please make sure the user doesn't delete the post so that our Quality
  Team can take a look.
Thank you again for passing this important post along to us. We really
  appreciate it!

I didn't know that TLG is so responsive to these kind of questions. I assume that you will post the final results? Does TLG even have a user here??

I'll definitely update this answer if I hear any more details. TLG takes quality very seriously. I've never seen anyone post here officially representing TLG, but I'd certainly be happy to see that. It's tricky on their end, as there is significant media training that employees need to go through to speak publicly for the company.

Have you heard any news from TLG?

@Aziraphale Nothing since I've posted this, I'm afraid.

It seems that TLG didn't come to a conclusion, or it was not important enough to get back to you.


text:
Can ScratchJr work with WeDo 2.0?
Now that ScratchJr is available on the tablet.
Is it possible to use it to control a WeDo 2.0 robot?

No, you can use only Scratch 2.0


text:
How do I have an else in conjunction with an if statement with two conditions?
I can't find a way to emulate an AND statement in a switch statement:
if (angle >= 10 and angle <= 30)
   ;// do smth
else
   ; // this is what I want

Until now, I just nested two if statements, but now I want to introduce an else case, but I don't want to duplicate the statements in the else condition two times (one in the first if, the second one in the nested one).
Is there a better way?

Hi SchoolGuy and welcome to Bricks! Which language are you using to program your EV3? (Hopefully you can edit your question to include that).

You can put all of the logic outside of the switch block and use the "Logic" input of the switch block. You can do exactly what you have described in pseudo code since there are "less than"/"greater than" blocks and an "and" block.


text:
2 Unidentified Printed Pieces, 2x3 Dark Grey Slope and Black 2x2 Tile
Below I attached two photos. I am not sure if they are from the same set or not. I was wondering what set(s) they are in.

Sorry for the bad quality, phone camera is meh, and only selfie camera works.

Can you describe the piece in words? Is it a lego brick with studs on top, a lego tile with a flat surface on top, a sloped piece, etc? How many studs by how many studs is it?

The slope piece is Slope 33 3 x 2 with Insectoid Scope Pattern from 9 (or 10) Insectoid sets from 1998-99.

The 2 x 2 tile is Tile 2 x 2 with Insectoid Logo in Triangle Pattern from 9 (or 10) mostly-Insectoids sets.

There are a few sets with both pieces.

Thanks Alexander, I looked at the five that had both of them, and I think it is cosmic creeper. Thanks for your help I have all if those neon and green pieces as well, but realized I must have another set because I still have some unused neon pieces.


text:
What are the dimensions of a technic axle?
I'm working on a LEGO compatible motor system that will be largely 3D printed.  I want the connectors to fit standard LEGO axles, but I haven't been able to find the dimensions online, and I don't have any on me to measure.
What are the dimensions of the cross-section of a LEGO axle. Is there a difference in size between the plus-shaped hole for and axle and the axle itself?

Do these have enough dimension details? LEGO Technic Axles

No, the length is easy to find, but I need the dimensions of the cross section

Specifically I need most the width of the ridges on the axle

Gotcha. The dimensions L x 0.4cm x 0.4cm is easy to understand, but do you have any idea what stud dimensions : 0.33 means?

It appears to be relative to a normal brick, for example the standard brick has stud dimensions 2 x 4 x 1

I found CAD files for LEGO technic axles here: https://grabcad.com/library/lego-technic-axles-1
and some gears which have holes for technic axles here: https://grabcad.com/library/lego-technic-gears-1
Using their online viewer I found the following dimensions (Which are a little inaccurate due to the limits of their online viewers tools. For more accurate and detailed dimensions download a copy of the CAD files)

This would seem to indicate (if accurate) an interference fit between the outsides of the axles and the holes (i.e. the hole is slightly smaller) which could be accurate as axles are usually tight.
Someone should also probably measure actual LEGO parts with some calipers for confirmation on these dimensions.

This is great! Thanks.  I'm traveling for thanksgiving, and I'll take my calipers to measure some actual parts.  I'll comment with results.

my caliper says 4.68 rather than 4.78 for cross width, and 1.83 vs 1.79 for cross arm width.


text:
Can you identify this Black Plane or Spaceship with black arches for wings?
Can anyone help me to ID this incomplete LEGO set?  It looks like a black plane or spaceship to me.

This is not a set,
The Tile 2 x 2 with Gold Crown on Light Bluish Gray Background Pattern  comes from 70404-1: King's Castle
the Brick, Arch 1 x 5 x 4 in Black does not appear in this set so it is probably a part of a MOC

The Arch's are probably of 7782-1: The Batwing: The Joker's Aerial Assault

As it turns out, it actually is part of a set. The stickered tile and other plates was just throwing off the search.

It's definitely the base of the Batwing from 7782-1: The Batwing: The Joker's Aerial Assault with a few random plates and tiles added on.

You can see from page 26 and 32 of the instructions that the structures are the same.

There are just a few plates added on top what do not belong, perhaps because someone started to build a MOC based on the Batwing's structure.


text:
Why do two EV3 bricks have different power outputs?
I have two identical box designs with EV3 bricks.  When I upload the same programs to both, one moves about twice as fast as the other.
Is there a reason that this might be happening?  Is there anything I can do to update it?

Have you checked the batteries? Maybe one has almost-dead batteries?

I have fully charged both batteries and they are both reporting full batteries.  I will try to swap out the batteries but right now it's not easily accessible from the design I've got, so I was just curious if this was expected or not.

Can you post your program, or at least the part with the Move blocks?

It's noticeable on a standard steering block - say at 75 power and going for a few rotations - on one brick that move may take a second, on the other, 2 seconds. i'll run and time it later today and post specific times, wheel diameters and rotations.

Are you sure the problem is with the ev3 bricks? Have you tried switching the motors? Maybe one is defective?

I didn't swap the motors, but if one of the motors was defective, on a tank steering block I would expect that if both motors were at the same power it would turn because one motor would be outputting power at a different level.  Given that it goes straight, it would mean that both motors are sending the same output.

Is it possible you have more tension or friction in one of the builds? I assume that you've got some gears, etc in there - are they all able to spin freely, or are some of them clamped a bit tighter? I agree this is probably unlikely based on your comment about "tank steering" as that would required the two sides to be equally stiff.

So it turns out the issue was a bad rechargeable battery pack.  When I replaced with fresh batteries the robot performed comparably to the other.

Some possible reasons:

A motor is defective
One of the brick has lesser battery charge
Firmware problem: make sure both bricks have latest firmware

it was the battery.


text:
What set is this sealed bag of pink, purple, and white bricks from?
I would like help identifying this bag of pink and purple LEGO bricks. It has three sets of eyes.

Based on the White Plate, Modified 2 x 2 with Bar Frame Octagonal, Reinforced, Completely Round Studs and the Dark Pink Brick, Modified 1 x 2 x 1 1/3 with Curved Top
This bag is part of 10696-1: Medium Creative Brick Box


text:
What is the selling rate per pound for individual colors?
I separated all my LEGO bricks by color so I can get max profit to pay closing costs on my family's home.  Is there a going rate per pound for individual colors?

Colour seperation matters more in which audience will be interested (AFOL's knowing they used some colour(s) more than others vs. parents wanting a pile for their kids) than for price.
Lots of things matter a lot more then the bricks being seperated by colour, some examples:

Whether the bricks have play wear
Whether the bricks have been miscoloured by sunlight
Whether the bricks have been exposed to smoking
The actual selection of bricks - i.e. are they all standard bricks or are they something less common in (some of) the pile(s)
Where you are in the world
...

So we don't have nearly enough information to give a good answer.
They are other questions on the site where people give estimates.

I would add to this that selling by the pound usually produces the lowest possible profit. Maximum profit is by selling parts individually, or by selling complete desirable retired sets in good to excellent condition. Separating by color has very little benefit, unless the color is rare; old grays, old brown, olive-green, dark-green/red/blue, and sand-green/red-blue. But even then, condition is very important, as well as what kind of mix of parts we are talking about. If OP mostly has standard colors, it's better to separate them by part, and/or condition, rather than color.


text:
What is the function of this device? What kit? Black remote with 5 buttons and 3 AAA batteries?

Some kind of IR device #s on cover 41305 #s on outside case 4252

LEDs appear to be IR transmitter and receiver. Red and white
LEDs also seen.

It's a Spybotics remote from 2002.

It came in 4 sets, and works with the receiver in those sets. I found this page which talks a bit about them.


text:
How much is Sheriff's Lockup #6755 worth?
I have set #6755, Sheriff's Lockup.  What's an estimated value without the minifig?

It depends on the minifigs and how much they are worth.

As Alexander said, it depends, but often a lot.

Will post this as an official answer once the question gets reopened, now that it has been updated: set 6755 is basically an older version of this set: https://www.bricklink.com/v2/catalog/catalogitem.page?S=6764-1. There are several listings on that page missing all the minifigs - they seem to go for ~$40 (or at least those are the current asking prices)

Set 6755 is basically an older version of set 6764. There are several listings on that page missing all the minifigs - they seem to go for ~$40 (or at least those are the current asking prices).

BrickLink has a price guide that will give you both the current prices people are asking for sets as well as any details on those sets sold in the last six months.
If you can't find your specific set, you may well be able to find a similar one (either in the same theme or similarly sized) that does have the data you want.
Typically "new" or "new in box" sets will sell for substantially more than "used" sets, and licensed figures will have more of an impact on prices than generic minifigs if they are missing.


text:
Can you identify this 3x4 black plate with studs only going down the middle?
I need help in identifying this piece so that I can search for it on BrickLink.
It is a platform for minifigures. It comes with the "mystery minifigure".

It is routinely used to display minifigs. The 3X4 area provides sufficient room for most minifigs. I've seen some special ones that take up more room than that.

You should be able to find this piece by looking up any of the collectible minifigures on Bricklink and looking at the set inventory.
This piece is the Tile, Modified 3 x 4 with 4 Studs in Center (88646).
It is classified on Bricklink under the category 'Tile, Modified'.


text:
How to make Lego Mindstorms EV3 robot go in reverse when move steering input comes from proximity sensor
I saw an program on the Lego Education page which makes a Lego Mindstorms EV3 robot gradually slow down as it approaches a wall. The info from the proximity sensor is used as the direct wire input of the Move Steering block, the nearer the robot to the wall, the slower the speed of the robot.
The problem is that my infrared sensor is on the rear of my robot (track3r). I would like to make the input to the Move Steering Block negative so that my robot motor moves backwards (in reverse) using this program. How do I do this? I can't make the output of the proximity sensor negative... can I?

Multiply the output of the proximity sensor by -1.

Aha, use (data wire it) the math block to multiply the output of the proximity sensor by -1 then feed it back (data wire it) to the steering block. Appreciate your time.

Actually, using the Invert Motor (blue) block from the Advanced Palette before the motor would probably have the same effect. I just read about it The Art of Lego Mindstorms EV3 Programming by Terry Griffin. The Invert Motor block reverses the meaning of the Power parameter for the motor connected to the selected Port.

Unfortunately, the Invert Motor block doesn't work with Move Steering or Move Tank blocks.


text:
"Unable to compile" error code with LEGO EV3 Arm Robot Program
Does anyone know how to fix this error with my LEGO EV3 program?
Unable to compile some documents for deployment:
Program.ev3p: Use of a block which no longer exists.
INI.ev3p: A My Block cannot contain a copy of itself.

I think the key phrase is "A My Block cannot contain a copy of itself." Look in the "INI" My Block for another copy of the "INI" My Block and delete it.

The main problem is that you have nested INI inside INI maybe cause you were trying to use recursion which EV3 does not support. It might also be that you have a copy of INI inside INI not connected to the play button script.
It may also be that your INI block contains another my block inside which contains the INI block in it and so on.
It would help if you uploaded the program or showed us snapshots.


text:
Good manufacturer/market for clear (transparent) bricks and plates in bulk?
I never realized how rare clear bricks are! I'm looking for an efficient way to buy clear 2x4 (e.g. 3001) bricks in bulk. On BO, BL, and Peeron there are very small lots and prices close to $1 and beyond per brick. On Alibaba there are some new compatible brands but they tend to mix random colors and styles, no pure bulk packs of the same brick in clear (white).
While I can patch together an order from the above, I'm wondering if there is a manufacturer that just sells pure lots of the same type and color so I can keep buying from them and not have it be a brand new search each time.
Or do any markets exist that unlike PL/BO/Peeron include competing brands rather than only Lego?

Clear 2x4 bricks might seem to be expensive because LEGO doesn't produce them currently (they stopped making them in 2006). However, a quick search on Bricklink sees them listed as cheap as $0.02 per brick, used, which is not expensive at all. Just make sure you look for the correct brick design - you want to look at 3001old.

Wow... I didn't know LEGO discontinued them. How sad-- clear bricks are the secret ingredient that fuels all our aircraft and spacecraft!


text:
Is there a way to identify the part number of a brick, just by using an image of it?
I am trying to get my brother a custom made gift of an enemy he likes from a game. However, I don't know the names of the parts, and to make my problem harder I have never seen some of these parts. I need to order them online, however, without the name or part number, I am at a standstill. If anybody can shed some light on how to solve my situation, that would be very much appreciated. Here is the design for reference:
https://www.reddit.com/r/zelda/comments/6k9p4b/how_to_build_your_own_lego_guardian_botw/

Could you tell which specific image you need help with?

I am not specifically looking for the part #s of specific pieces, as there are to many that I don't know the names of. Rather, I am looking for a method of determining the part #s and names of the pieces. I edited my question to make my problem a bit clearer. Sorry for the miscommunication!

@UnorthodoxParadox Welcome to Bricks.SE! I've closed this question as a duplicate. Hopefully the answer on the other question helps you out. Certainly feel free ask additional questions if you get stuck on identifying specific parts. We're happy to help!


text:
How should I transport my big LEGO sets?
I'm moving and I have some big LEGO sets (Police Station, Fire Station, and Ultra Stealth Raider).  How should I pack them so they won't get shattered to pieces in transit?

You should disassemble the buildings to smaller parts, then pack these parts with bubble foils. After that, you can place them in massive plastic boxes. LEGO bricks aren't really fragile.


text:
How can I build a brick-built monorail track?
LEGO haven’t released a new monorail set since the 90s, and the track parts that were made are very expensive and hard to find.
I am interested in building a brick-built alternative. I am particularly inspired by the build shown here.

Criteria
Vehicle

6 to 8 studs wide
running on rubber tyres
motor-driven

Track Elements

straight – unlike the original, a central rack is not necessary for level or smooth gradients.
curved – can be fixed angle or flexible.
incline – can be fixed angle or flexible.
track supports
track switcher (Optional)

Parts

Cannot use existing monorail parts (including the #2681 and #2680 supports).
Avoid rare, expensive parts, or parts out of production.

Yes, but the motor would be contained in the monorail carriage so it shouldn't affect the track design too much. (Apart from the inclines)

Great question! I'm excited to see what folks here come up with.

so it shouldn't affect the track design too much – Well, you have to have some cogs or rubber wheels to transmit the force and something that connects them to your motor. The main problem is not designing the track but something that properly can drive on it.

@Wrzlprmft Correct. This is my inspiration for the train, in the sense that the motor and battery box will be contained in one of the carriages.

What it could have are rubber wheels gripping sideways onto the track (this is just part of an idea so I don't know how the track would be made) and motorised from inside the train. e.g. the wheels stick out the bottom and on flat track are horizontal and quite tight on the sides of the rail.

There's an article about this topic in the November 2018 issue of HispaBrick magazine.
In addition to a nice interview with the designer (Masao Hidaka), the article shows off some of the techniques used for building the rails:

Technically, the design matches most of your specifications.

It even includes a rather complex motorized switch:

Here's a complete layout:

I'd definitely encourage you to give the full article a look.

Have a look at this youtube channel: MasaoHidaka The Track is made up with standard bricks and he managed to create nice curves and even switches. The switches are quite part intensive though.


text:
Determine assembly steps from LXF file
I’d like to build a MOC of a Technic vehicle that was posted online using the provided LXF file of the completed model.
I was able to open the LXF file with both Bricksmith and Stud.io, but, as far as I can tell, it is not broken down into a sequence of assembly steps. In other words, both programs shows just the completed model.
I’d like to know either: (A) how to view the intended/embedded step-by-step instructions, assuming they exist, and/or (B) if there is a common/best practice for manually determining an assembly order when all you have is a completed model in an LXF file.
FYI, the model I want to build is the awesome looking Chili Crawler by PunkTacoNYC. It can be seen on YouTube, and the LXF file is available here.

See also the options here: Do any programs exist that allow you to build your own LEGO manuals?

The LXF file contains the complete model as created with Lego Digital Designer (the Lego CAD tool from The Lego Company). The model usually doesn't require to have building steps as they are (always) automatically generated from the model.
For normal, non-Technic models, Lego Digital Designer (LDD) is able to create automated building instrutions. My experience with LDD and Technic models / MOCs is that you have good support for designing the completed model, but that for the generation of building instructions you're better off with other tools.
You can translate an existing LXF file into an LDraw model (file extension: .ldr), but for some exotic (read: Technic) parts, the translation of LDD parts and LDraw parts is either incomplete or has problems with part orientation. This means that you may have to do manual edits to your model in order to have an (almost) complete translation into LDraw file format. See e.g. this site for details.
One advantage of the LDraw format, is that you can define "building steps" and sub assemblies in the design, which makes the generation of complex building instructions easier.
A tool for creating building instructions from a LDraw model, is LPub3D. Otherwise I'd suggest using a Lego CAD tool such as LDCad.

I did end up converting the LXF file to a Stud.io file, which, like LDraw, allows the creation of steps. I could see instructions in Lego Digital Designer, but the steps were not in the proper order. That makes efficient Technic building painful, if not impossible. As far as a ‘best practice’, which was part of my question, I suspect one is methodically disassembling the CAD model, which appears to create building steps in reverse. I wonder if this method has worked for anyone else — or if it hasn’t.

Starting from LDD files and LXF, a good software is Blueprint from msx80
https://www.eurobricks.com/forum/index.php?/forums/topic/108346-software-blueprint-a-building-instruction-generator-for-ldd/
With this, you can organise how you want the pieces to get assembled (by default the auto-generated steps are not always optimal), then export a PDF, I think it's pretty great.

You can use LDD (Lego Digital Designer) the official LXF viewer by Lego. This allows you to create building instructions to view or export to html.
You can also use this software to build models, and i find it much better than other softwares since it is simple, with easy UI.


text:
How to fix the 4.3V output supply of a NXT 2.0?
I have a Mindstorm NXT 2.0 from 2007 (PCB code: 62115.40H) at which the sensors except the simple "Touch sensor" are no longer working. Also the tacho-signal of the motors do no longer work. (The motors work but do not stop after e.g. 5 rotations)
By looking at the schematics of the slightly older NXT (1.0) I could figure out that the problem seems to be caused by a defect in the 4.3V output supply. So I opened the housing and measured at TP79 of my NXT 2.0 the voltage of IPOWERA, IPOWERB, IPOWERC, IPOWERD and POWERMA, POWERMA, POWERMC. The voltage was not having 4.3V while the 5V supply "VCC_RS485" from which the 4.3V output supply is generated was fine.
My problem: The circuit which generates the 4.3V output supply from VCC_RS485 was changed in the NXT-2.0, while I can only find the schematics of the older NXT (1.0). This made it for me impossible to find the defective component (since nothing looks obviously defective)
Does anybody know how to fix the 4.3V output supply of an NXT-2.0?
Or does anybody know where to find the schematics of the NXT-2.0?

I found a schematic from what seems to be the NXT 1.0 here: https://www.lego.com/en-us/mindstorms/downloads  I am only seeing  5V and 3.3V power supplies listed in the documentation, is the 4.3V in your question a typo?

Josh, the 4.3V are not a typo. As you can see in the PDF "LEGO MINDSTORMS NXT Hardware Developer Kit.pdf" available on the link you have mentioned, pin 4 of every sensor and motor connector provides a 4.3V supply voltage for the sensors (including the sensor inside the motors). There is no voltage regulator for the 4.3V. Instead it is derived from voltage VCC_RS485, which has 5V. The circuit for that (of the NXT 1.0) is on page 3 of the schematics. Check TP79.

Finally I've found a solution. It is not perfect since I wasn't able to find the schematics of the NXT-2.0 nor could I reverse engineer it. But this workaround seems to work pretty well.
This workaround works at the following conditions:

You have an NXT-2.0 (not a NXT-1)
The 4.3V voltage for the motors and sensors is no longer there (Voltage at C61 is zero.)
The 5.0V voltage VCC_RS485 has still 5.0V (Voltage at C57 is 5V)

As you can see in the image below I soldered a 1N4007 rectifier diode between the positive terminal of capacitor C57 and the positive terminal of C61. The cathode of the diode has to touch C61.
Ensure not to touch the test-point T41 close to C57 since this should have 3.3V on NXT-2.0 (while it had 5V on NXT-1).
A silicon rectifier diode causes usually  a ~0.7V drop. So it makes 4.3V from the correct 5V source. If you don't have an exact drop of 0.7V don't worry: The NXT motors work also with the Lego-EV3 and according to the spec. of the EV3 that brick sends even 5V directly to the motor-sensors. (So even a wire instead of the diode might work - but I used the diode to stay on the safe side)
To solder the diode you have to open the NXT and to disconnect the battery holder, which requires some desolder work.
Dependent on your skills this might be some tricky work. Please don't blame me if this kills your NXT totally. Only do it if your feeling qualified to do it and if you've understood the explanations above.

I was in same situation. In my case I fixed the problem replacing C61 capacitor that was shorted. I have found this schematic, but it seems not corresponding to 2.0 also because I can't follow it.

Welcome to Bricks! I'm glad that replacing that cap fixed the issue for you! Hopefully this information will be helpful to others as well. How did you identify that this was the problem? Could I just put an ohm meter across the C61 terminals to identify that it is shorted and needs to be replaced?

I'm not an electronic professional, but I know that a cap doesn't conduct DC current and electrolitic capacitors are between the more error prone components. So with schematic in hand and the picture that @Holger posted, I put the multimeter in continuity mode and tested C61 cap. It beeped. I was lucky because that was my first try and surely the only problem I could have fixed.

Great! Thanks for sharing!

I'm so glad I found this post! I had left the batteries in the NXT for too long and corrosion had broken some of the connectors, which I had just managed to replace. However, I later realized that I had the sensors and motors issues described above. After seeing this post, I had not much to lose and decided to disconnect the battery holder and test C61. Sure enough, it was shorted and I replaced it quite easily.


text:
How do I see which stores have all the parts I want on Bricklink?
If there are four different parts I am wanting on Bricklink, is there an easy way to see if one shop has all four? I would want to get it from one shop to reduce shipping. I know I could do it the long way, but if I don't find one early it could take a while.

Not sure if this answers your question, but what I did was I added the bricks I wanted to my wanted list. Then I clicked Easy Buy. Another way is to click on your wanted list, click buy all in the upper right hand corner, and this you will see a scroll down tab/list that is labelled sort by. Just select min buy and click auto select. However, I'm not sure about the shipping problem.

I just want to find them all in the same shop.

Sorry, not sure about that...

The way to do it is to make a wanted list in BrickLink, selecting all the different pieces and quantity of each that you want.
Then select all of the items by checking the boxes next the items you want or selecting the upper box to select them all and then click the green buy items button, this then brings up a list of stores selling the items.  The list is sorted by which store has the most of your selected items available to sell.  The two important columns on this list under each store is "unique lots" which is how many of your different parts the store has followed by "item count" which is the quantity of those items they have.
If you then click on the individual store, their shop will have a wanted list tab, which will show you everything on your wanted list that they have to sell.
It's not uncommon to have to purchase from multiple shops to get everything (different items and quantity) you need/want.  So it often requires checking multiple stores to combine it into the smallest number of purchases, I am not aware of any automated method of doing this, I just end up opening multiple tabs in my browser from the list of stores generated by my wanted list query and figure out the best option myself from there.


text:
What is this light grey LEGO plate with six sides (hexagon)?

I've been unable to find this specific piece's name, just for the reason that it is a very unorthodox piece.

Informally, it's known as the Nexogon.

Bricklink calls it "Plate, Modified 6 x 6 Hexagonal with Pin Hole". The part number is 27255. It's original use was as a shield in the Nexo Knights line in 2017, but it has appeared in a few other sets since then.

If you're interested in ways to use this part, New Elementary did a whole series of posts from different builders when it was first released. The unique shape and different connection families open up a lot of fun opportunities.

So beautiful, that is

Is there any name for that type of irregular hexagon? I couldn't find any in MathWorld. Also, here's more fan stuff on Nexogon:https://www.brothers-brick.com/2017/01/19/new-nexo-knights-nexogon-part-analysis-new-elementary-guest-post/

From their image, the long:short sidelengths have ratio 2:1

@smci: You can see this hexagon as a truncated equilateral triangle.

Thank you so much! I have been having such a hard time trying to identify this piece, but you made my job so much easier. Thanks again!

This is what I managed to create with the Nexogons:

Flickr Album: https://www.flickr.com/photos/162108633@N02/albums/72157688876724660


text:
Do all Technic bushes (3713) have the LEGO label on them?
I have just found out that many of my Technic bushes (3713) do not have "LEGO" printed on them. Does this mean they are fake?
I know that many parts were produced in several variations.

Technic bushes didn't always have LEGO stamped on them.
I don't remember exactly when I first noticed this, but some years back they started stamping LEGO onto a bunch of different pieces that didn't previously have it.
I suspect they did this because people were knocking off more and more of their pieces.


text:
I need download instructions for this set, but I don’t know the number, light green and black pieces

I need to download instructions for this set, but I don’t know the set number.

This bag is from 70736-1: Attack of the Morro Dragon
Based on:

6116600: Ninja Sword

6109561: Blade 10M W/Ø3.2
6039194: Stone 1X2X1 1/3 W. 2 Plates 2X2

and a double check with the instructions.


text:
How to get the Millennium Falcon 75192
Just like everybody else, I'd like to get the new 75192 set. Unfortunately, information about that is rather spotty. The lego shop website used to write "soon", currently it writes "unavailable". The lego shop hotline says you may get it in a shop. When you call the shop, they don't have it. They sometimes get sets, but they are sold out in seconds. The online shop used to take reservations, even prepayment, but they stopped, the shops seemed to have done the same, but they stopped too.
So my question: What do I have to do, to get the 75192 before christmas?
Does somebody here have it? How did you get it?

If you absolutly want the Falcon before christmas
and if money is not a factor you can try 3rd party sellers like Bricklink or Ebay
It will cost you more than the offical price and  there will be shipping costs (it weighs 13150 gr.)

Thanks, I'm aware, that I can buy it for a lot of money. Unfortunately, money is a factor. I was hoping for hints, i.e. shops that still accept pre-orders or deposits, hints of the next deliveries and such things. And tales on how current owners got theirs...

At my store, they said that it would be in stock in February. I think current inventory is going to a wait list of VIP members who were in the store on launch day. They also said that LEGO didn’t intend for it to be exclusive and that everyone should be able to get one. They were just surprised about interest!

Surprised by interest? That must have been a joke :) They probably surprised the owners of the 10179 Falcon that planned to sell it for a couple of thousand euros/dollars. I guess that now many people will rather get the new one for 800 Euro instead of paying much more for the 10179.

It was in a status of "global shortage" as the demand is way ahead of supply - some official channels have a waiting list of hundreds to be filled as new stock trickles in. However, Lego has appeared to ramp up their supply, and it is available in major online channels as of May 2018 (https://www.zoolert.com/toys/lego/star-wars//millennium-falcon-75192/), this might have something to do with 4th of May.
This should last until 2019/2020 as the model stays under official production.


text:
What are the set numbers for these Star Wars and Police sets?
I recently bought some old sets and stumbled across these 2 set-remains. One is obviously a Star Wars set, maybe someone knows the number? I wonder if the other one, the future police, is a MOC instead of an official set?

The police vehicle is from  7035-1: Police HQ

based on Wedge 6 x 2 Left with Police World City Pattern

The last picture is from
7748-1: Corporate Alliance Tank Droid

based on Light Bluish Gray Dish 10 x 10 Inverted (Radar) with SW Tank Droid Pattern

thanx Syberion. never heard of World City. just when you think you know it all... ;-)


text:
What causes certain LEGO parts to yellow over time, and how can this be prevented?
I've noticed that certain LEGO colors have a tendency to turn yellow over time. For example, I have a set of 4 "white" wheel hubs that are all now various shades of yellow:

I know there is already some information on how to fix this, but I'd like to understand why this happened and how to avoid it. What causes LEGO parts to turn yellow, and what specific steps can be taken to prevent this damage?

There are many things such as dirt and chemicals that can cause elements to change color. Dirt can easily be washed off, but certain contaminants such as cigarette smoke can stain plastic.
The most common issue that causes LEGO bricks to yellow is interaction with ultraviolet light, most commonly from the sun. The simplest way to prevent this is to store parts indoors out of the way of even indirect sunlight.
There are some tips for correcting this issue in another question, and more details about the chemical process that causes UV light to degrade ABS over on Chemistry.

I don’t think it’s because of light. I kept my minifigures in a locked drawer away from any light (and anything that you mentioned) and they still turned yellow.

Were... were the minifigs yellow before?


text:
What sets are these pieces from, rock platforms and walls with large cannons
I think I have a couple of sets I'm trying to put together for my son that were my brother's when he was young. Probably from around year 2010 or earlier. Looks like a black castle or dungeon. Also with gargoyles and broken wire cells. Also have large rock platforms and rock walls. Please help. I've searched and can't even find the pieces online.

It looks like you have some Mega Bloks sets.
I can't say for sure if these are sets you have, but I found similar pieces in these sets:
Dragons Battle Gate

Portal of Fire

I don't know of any resources for non-LEGO instructions.

Red cannons from second foto from mega bloks pirates: Shark escape, Plunderer's port. Gold cannon was in many sets: Mutiny isle, Captain cutlass' stormstalker, Port royal…
More dragon sets: Tower, Warriors fortress, Sorcerer's lair.


text:
Which clone brand and set do these pieces belong to, rock platforms and castle walls?

Please help. What set is the rock platforms from and the other rock pieces? The castle walls too?

Most of these are mixed Mega bloks Dragons sets from the Dragons series.
The rock platforms are from Dragons: Raiders Keep #9650  (more pictures).

There is also a window from #9885 Marauder's Cliff.


text:
Which Lego Technic sets are officially combinable?
Lego sets 42058 Stunt Bike and 42059 Stunt Truck can be combined together to build a bigger truck. We can find official instruction on the LEGO site.
Are there other pairs (or larger groups) of sets like that?
I am particularly interested in Technic sets released in the last couple of years, but it would be great if there were a comprehensive list of such sets or a way we can search them.

Related: https://bricks.stackexchange.com/questions/8994/

Whenever a LEGO Technic set is officially meant to be combinable with another set, it is mentioned right on the box, as well as in the instruction booklet, and also in the official set description at the Online LEGO Shop. The combined instructions are posted at the LEGO Technic website.
As far as a list, I don't know of any place that has a comprehensive list like that, but I agree it would be very useful. I do know, however, that the two LEGO Technic Pull-Back Racers released each year since 2013 can always be combined with each other with downloadable instructions. Here is the list of the sets:  https://brickset.com/sets/list-15258

Famous example from this year: you can combine 3 of the anniversary sets (one of them is the Telehandler) to create a modern version of the legendary Car Chassis technic kit from the beginning of Technic.


text:
Are these bricks old LEGO/Duplo clones?
Can anyone identify these bricks, which I suspect are LEGO clones.  They may be more than 30 years old.
I bought them on ebay as Betta Bilda from LEGO/Duplo dealer. Some BB was included, but these are unknown to me, with an extensive BB collection.

The underside of the bricks is hollow and with apparently random numbers - they aren't part numbers because they are different for the same part and sometimes the same for different parts.  Window frames have no top studs.

I took a good look through many posts with similar questions, but found nothing that matched.  Many Google reverse images searches kept pointing at real LEGO/Duplo, before I noticed this place.
Usually I can identify unknowns like this, but these are a real challenge.
Edit (Nov 29, 2019)
Some comments have asked for clarity on size of these bricks.  The majority are close to if not identical to 8 stud LEGO, although there are also 2 and 4 stud bricks too.  They clip to Betta Bilda pieces, in a similar way to authentic LEGO. The window frames appear to be confirmed by two comments as 1950-60 LEGO, but additional insight would still be appreciated.

Don't know what brand they are, but I'm pretty sure they were around in the 1980s, since I have some from when I was little. Might help with dating them a bit...

Matthew - thanks for that, any help is appreciated.  They are hard to date by condition, but could be slightly newer than the 60s Betta Bilda they came with.  Since my original post I found some similar looking parts under the question "Lego variant, or is it?" with answers suggesting 60s or 70s.  There was also one suggestion that they might actually be non-ABS Lego from the 60s.

Those window parts are remarkably similar to some I had back in the 70s. No studs on top, and the hinge points look identical. They were authentic Lego.

I keep happening upon this, and the 2 or 3 others that seem very similar or the same.  The problem is that here it is suggested that they're Duplo sized, while some of the other questions state that they're the same size as a regular Lego brick.  Even though I've never seen Duplo sized windows like that doesn't mean they aren't, Which is it? Duplo sized or regular Lego sized?  I may actually have an answer to some of these questions if I knew.

@JohnnyB  Thanks for taking the time to comment.  My apologies for not making the sizes of the bricks and windows more clear, perhaps I should have included a ruler or something for a size reference.  The bricks and frames are regular Lego size.  I don't have any Lego to check compatibility, but these bricks are generally compatible with Betta Bilda parts, which are themselves generally compatible with most regular Lego.  I hope that clarifies the sizes of the pieces in my photos at least, although I can't comment on others you may have seen elsewhere.

the red windows looks like the old ones I have, and its lego from 1950-60.

@Lisa Astrup  Thanks for your comment.  Your knowledge confirms what at least one other has said regarding the likely age and authenticity of the window frames.  I feel that I can begin to trust that they are authentic Lego from around 1950-60, making them the only Lego pieces in my brick collection!  I still hope to find some confirmation of the origin of the bricks, so perhaps it is time for me to do another thorough internet search.

I advise that you contact Lego support and ask Them since we could guess pretty much all day and yet even if we Do find the correct answer, we wouldn't even know and we'd keep guessing. That's your best bet.

@mindstormsboi  Thanks for that suggestion, as I was not aware they might even be interested.  If as a number of replies have suggested there is a small possibility that they are older Lego pieces then it may be worth asking them.  I will try after Easter.

Hello Paul, did you forget to ask Lego Customer service about these parts? Just a reminder.

Did you ever get to the bottom of what these are? I've recently acquired a fair number of identical bricks, windows and roof parts and I'd love to know what they actually are. I've hunted around but this is the only place where I've found a photo of what I have.

@Malcolm Thanks for the recent comment and I am sorry that I didn't see it sooner.  It is interesting to discover there is someone with identical bricks, but so far this year has not been the best time to pursue this with Lego Customer Service. I will contact them tomorrow (Sept 11) and see what advice they can offer.  A note on their website suggests 10 days for routine email replies, so I will update here as soon as I can.

@mindstormsboi  I am sorry that I did not respond to your follow up comment in June, but after the more recent comment about similar pieces I will call Customer Service at Lego tomorrow (Sept 11) and see what insight they can offer, and if I should address email to a department or individual.

@mindstormsboi  Response from LEGO customer service received, and they say the bricks are not LEGO, and they don't recognise the the clone either. I have decided to answer my question, as I suspect no further progress can be made, if even the LEGO experts can't identify the bricks I have.  I appreciated your suggestion and I was impressed with the friendly and helpful attitude of the LEGO representative.

@Malcolm  The answer I received from LEGO confirmed my bricks are not LEGO and they could not offer a name for the clone manufacturer.  Sorry I can't help more, but the fact that you also have similar bricks must mean that an answer can be found somewhere online.  If I find anything helpful I will try to let you know through this forum.

Which country do they originate from? They remind me of the bricks I had in the 70s in Bulgaria. And they were certainly not original Lego. Probably were not made in Bulgaria but, rather, somewhere else in Eastern Europe or USSR.

@Nick Sorry I don't know where the bricks came from originally, but I bought them in the UK from a UK seller of mostly Lego on ebay.  You may be right that they came from Eastern Europe, as they don't appear to be common. Thanks for your info.

As suggested by @mindstormsboi I contacted LEGO customer services and sent them a link to this question as well as many additional photos.  The information was passed to their expert team and the answer that came back was "they believe that these are not LEGO® parts". They were not able to identify them as a known clone type. I feel obliged to accept that as a definite answer, although it leaves unknown who actually manufactured the bricks I have.  I will continue research into that question, but elsewhere.
The customer service team member also gave me two interesting links to a fan created website with some of the history of LEGO parts, as well as section covering many of the clones and similar brick building sets.  I include the two links below, as they may be of interest to some who find this question and answer.
https://www.inverso.pt/legos/
https://www.inverso.pt/legos/clones/texts/mobitec.htm
Thank you to all who contributed their knowledge, experience or point of view.

I just spent waaay too long looking through the sources you linked, and then the sources they linked, and so forth. Rasti appear to be the only lego clone with holes through every stud. Even then, the bricks in the first image you posted probably are not Rasti, as the stud holes are too small. It's a mystery!

The only blocks you show that seem like they might be genuine lego are the windows. According to inverso, the very earliest lego windows lacked what became the signature studs on top

From the LEGO Wikipedia Page "1961 and 1962 saw the introduction of the first Lego wheels, an addition that expanded the potential for building cars, trucks, buses and other vehicles from Lego bricks. Also during this time, the Lego Group introduced toys specifically targeted towards the pre-school market." here is a picture of these first-ever Duplo bricks from the 60's look similar?

Also, the Wiki page says in 1958 they added the famous circles in the bottom of the brick to help them connect.

Thanks for your contribution which has kick started my research of this mystery afresh.  The wiki Lego history mentions that Duplo did not go on sale until 1969, so the lack of circular tubes on the underside of Lego bricks would have been 11 years earlier.  However, adding 1969 to my Google image search for Duplo blocks did turn up one photo of bricks almost identical to mine on the Eurobricks forum, which showed a set of Duplo as issued in 1969.  Mine could still be clones though, because I cannot find photos of the underside with the strange numbers that are on mine.

My understanding it that Lego use to put the mold numbers in the underside of the bricks.  There is a great video on Netflix, the show is called The Toys that Made us, the Lego story is under Season 2 episodes which kind of shows the molds with the numbers that look just like that.

I don’t exactly know if it is LEGO,
But it may be an old version of LEGO. The numbers also could be the date the were made or a factory code.

Thanks for your thoughts.  I suspect the numbers might relate to moulds or machines, so they could monitor how many pieces were produced from them or which one had problem if defective pieces were observed in quality control.  The feedback from other contributors has been mixed, but most seem to think they could be LEGO or DUPLO from the 1960s.  My question is over a year old now, but I remain hopeful that one day someone who has some solid evidence can confirm what they are.

I don't think they are LEGO due to the holes in the middle of the studs. LEGO pieces also say "LEGO" somewhere on them, so I bet that they are a 3rd party brand.

Hi User 119! Your points are correct regarding the LEGO elements of today. But as the OP mentioned, these bricks may be more than 30 years old. Are you sure your observations are correct for that time period too?


text:
What happened to Olivia in the 2018 Lego Friends sets?
If you've been following the information about the 2018 Lego Friends sets, you may have noticed that some of the characters look a little different. Most characters look fairly similar with minor updates. However, Olivia appears to now be a different race:
Olivia before 2018:

Olivia in 2018:

What is happening here? Has Olivia been replaced?

Many adjustments have been made for 2018. The five main characters all still exist, but they have been changed somewhat. This was brought up on the Lego Ambassador Network, and generated enough interest to get an official response from the Friends team in Billund:

Every year we strive to innovate and make our products even better for
  children all over the world. A lot of effort has gone into the
  development of the LEGO characters and universes across our entire
  product range, so it makes us very happy  when changes are noticed.
LEGO Friends in 2018 looks a bit different than what it has in the
  past. To be specific, the 5 main characters have a slightly different
  look but also the city and the citizens of Heartlake City have
  changed.
But what are the reasons for the change?
Firstly, we want to assure you that all 5 friends are still there in
  2018. Andrea, Mia, Emma, Stephanie and Olivia – they all still exist! Also the character’s main interests and personalities remain mainly
  unchanged.
What you will see in 2018 is an evolution of LEGO Friends, a
  progression of the story and characters to make sure children get an
  even greater play experience. Every year more than a million children
  and parents reach out to us and share what they love and what they
  would like to change. In the LEGO Friends range children told us that
  they would like even more differentiated characters and also suggested
  improvements to Heartlake City.
We always take great care to listen to input from children, and the
  LEGO Friends team has worked hard to make even more engaging and
  relevant experiences for children – and also make the LEGO Friends
  universe more true to the actual world children live in.
Taking a starting point in reality, we’ve made the characters more
  diverse in their appearance and have added more depth to their
  personality. And of course, they still live in Heartlake City. But
  just as the characters have changed, Heartlake City has become more
  differentiated and rich. There are different districts and there are
  other citizens that play a more active role in the story.
The changes we have made does not change the fact that previous and
  new LEGO Friends sets will cater for great building and play
  experience in 2018 and beyond, and we hope to inspire even more
  stories and play opportunities for children in the future.

Hidden in there is "we’ve made the characters more diverse", which sounds reasonable. 4 out of 5 on the first box look caucasian to me, which doesn't seem very representative.

@Craig: So the answer to the question is "Yes, Olivia has been replaced to make the characters more diverse."?

Nope, just reskinned - now there are finally more skin and hair options which is only a good thing for variation in Lego.


text:
What strategy should FLL teams use to pick their next robot mission?
FLL teams compete by running their robot on missions.  The robot leaves the base, does a task, and then returns to base.  Each mission is worth a few points.  The goal is to collect the most points in a 2 and 1/2 minute run.
The tasks are at different positions across a 4' x 8' obstacle course.
Some missions are easy, others very difficult.
Some missions require intricate Lego constructions.  Some require difficult programming.  More than one task can be accomplished before returning to base.
What strategy should an FLL team use to pick the missions to attempt?
Given there are about 15 missions that each take somewhere from 10 to 30 seconds to run and the team has 5 missions that work most of the time and the 5 missions consume the 150 seconds available, what should the team work on next?

This is a bit too abstract for me. Can you somehow illustrate what the missions are and what the course looks like? I think I have seen a course you describe in a school project. However, it is difficult to tell at the moment.

First off, that website is horrible, so much clicking on expandable things, a terrible UI.
The PDF download of the rules is better.
Looking through the missions I notice a few things:

None of the missions have significantly bigger point values to make them obvious choices over other missions.
The missions are all based on end state and cannot be repeated for multiple points

So it appears you should simply try to maximize the number of successful missions accomplished in the limited time period.
Some missions should obviously be combined since they are handling similar pieces and would be easily doable with the same robotic manipulators.
Such as:

Moving pipe sections for: pipe removal, pipe install, pipe construction
Moving Big Water pieces for: fountain, flower, and water collection
Manipulation of levers or handles: flow, water treatment, faucet
Picking up, moving, and aligning pieces in the field: pump addition, rain, manhole covers, sludge, water well
Moving objects from the base onto the field: tripod, water well, slingshot

Also some missions must be done before other missions:

Manhole covers removed before a tripod is placed
Pipe removal before pipe install

The best bet is to pick a group of tasks that a single robot build is likely to be able to do well and go from there.
Some thought might be given to completing the furthest missions first, so that traveling past already completed missions doesn't mess something up.
You might start by sorting the task into groups like I have done, try to judge the inherent difficulty of the mission, and rank them comparing with point totals.
On a final note: As this is a competition for children to learn about engineering and robotics, you should really just explain the rules/different objectives/point values and help the kids pick a strategy themselves.  The planning process itself is as much engineering as the programming and building of the robot.


text:
Round Plate 1x1 Dimension
What are the dimensions of the following Lego Part:

I know of the basic dimensions shown in this graphic.
I believe, the diameter of the largest Ring is 7.8mm.
However, I'm missing the following two measurements:

diameter of the base-cylinder
height of the base-cylinder
height of the small big middle cylinder

Is "lego-dimensions" the right tag? I think it refers to the LEGO computer game thing.

Actually Im trying to model some lego pieces for AR-tracking, for whcih i need acurate measurements - so it has nothing to do with the computer game ;)

This Bricks question has additional information on LEGO sizes. First I thought your question is a duplicate, but it is not.

You can derive detailed part geometry using the LDraw parts library. LDraw provides freely accessibly models for nearly every part that Lego has produced. I'd recommend parsing these parts rather than rolling you own models if you're going to be using many parts.
Here is the relevant content of the file representing a 1 x 1 round plate:
1 16 0 3 0 -1 0 0 0 -1.25 0 0 0 1 stud4.dat
1 16 0 3 0 -6 0 0 0 -1 0 0 0 6 4-4disc.dat
1 16 0 3 0 -2 0 0 0 -1 0 0 0 2 4-4ring4.dat
1 16 0 0 0 10 0 0 0 3 0 0 0 10 4-4cylo.dat
1 16 0 0 0 2 0 0 0 1 0 0 0 2 4-4ring4.dat
1 16 0 0 0 2 0 0 0 1 0 0 0 2 4-4ring3.dat
1 16 0 0 0 1 0 0 0 1 0 0 0 1 stud.dat

LDraw uses its own custom file format. Units are in LDU and represent about .4mm.
I won't try to describe the format in detail, but lines starting with 1 simply include another file that is translated, scaled, and rotated based on the included transformation matrix.
Base cylinder
We can break the part definition down to its components. The outside of the base cylinder corresponds to:
1 16 0 3 0 -1 0 0 0 -1.25 0 0 0 1 stud4.dat

stud4.dat represents a ring that could fit a stud inside of it. It's present in many parts (e.g. underneath 2xn bricks and plates). It looks like this:

Its outside is represented as (from stud4.dat):
1 16 0 -4 0 8 0 0 0 4 0 0 0 8 4-4cyli.dat

The primitive 4-4clyi.dat (4 fourths of a cylinder) is a basic open cylinder:

Most LDraw primitives including this one are normalized size 1, so we start with a cylinder with height 1 and radius 1. A transformation matrix is then applied:
1 16 0 -4 0 8 0 0 0 4 0 0 0 8 4-4cyli.dat
            |               |
            +-------+-------+
                    |

                8   0   0
                0   4   0
                0   0   8

Now, it's a cylinder of height 4 and radius 8. This was also transformed by the original inclusion of stud4.dat:
1 16 0 3 0 -1 0 0 0 -1.25 0 0 0 1 stud4.dat

We need to multiply its height by 1.25 to get a cylinder of height 5 and radius 8. Here's the final result:
Base height = 1 * 4 * 1.25 = 5 LDU * .4mm = 2.0mm
Base diameter = 2 * 8 LDU = 16 LDU * .4mm = 6.4mm
Middle ring
If you followed all of that, the middle ring is easy. It's outer wall is represented by:
1 16 0 0 0 10 0 0 0 3 0 0 0 10 4-4cylo.dat

So, it's a cylinder with a 10 LDU radius and 3 LDU height:
Middle ring diameter = 2 * 10 LDU * .4mm = 8mm
Middle ring height = 3 LDU * .4mm = 1.2mm
Checking our work
The height of the base and the middle ring sum to 8 LDU, which is good because this is the correct height for a plate like this.
As you noted, you expected the outer ring to be 7.8mm, but I calculated it as 8.0mm. The reason for this is that LDraw uses the ideal sizes of bricks for its library. This is convenient for collision boxes in the theoretical world, but in reality, Lego has to make parts slightly smaller so that they fit between each other easily. As you mentioned, this tolerance is about .1mm per side, so we're in the right neighborhood with our calculations.
In addition, most things in LDraw end up rounded to 1 LDU, so measurements have a tolerance of around +/- .2mm. Most Lego parts fit very nicely into a 1 LDU grid, so this isn't usually an issue. I'm not sure what level of precision you require, but my hunch is that the LDraw library will get you close enough for your needs.
Good luck with your project, and let us know if we can help with anything else!

I have a micrometer for measuring with 0.1 mm precision. Using that I measured following lengths:

diameter of top cylinder (stud): 4.9 mm
diameter of lower cylinder: 6.4 mm
diameter of middle ring: 7.9 mm
height of middle ring: 1.0 mm
total height of the plate: 5.1 mm
inside diameter of lower cylinder: 4.9 mm (no surprise)

Can anyone confirm or question these lengths? I would be interested in knowing whether I did it right.

It's a "micrometer" in English, not to be confused with a "micrometre", which is 0.001mm

Thank you. Now I also know the German word : Mikrometer

The German word I know for this tool is "Messschieber".
Also I'm confused: According to the graphic i linked (souce is german wikipedia) in my original Question, the diameter od the top circle should be 4.8mm instead of 4.9

There are several translations, as usual for highly specialised items. I measured several times the stud and also the inside of the tile. All times it was 4.9 mm or VERY close to that value.

In stud.io, the middle ring is thicker than 2 LDU.  2.5 LDU looks about right.


text:
Augment LEGO City Mobile Command Center 60139 with Power Functions LEGO 8293?
I have the LEGO 60139 set for my child. If I buy LEGO 8293, will I be able to motorize the truck in 60139 set?

You are not likely going to be able to add the power functions motor to this set without some major modifications. The truck in the set uses pin type wheel connections, the motors normally use technic axle style wheels, and there isn't really any extra room internally to place the motor.
For reference:

Set 60139

Set 8293

You might be able to contain the battery box in the trailer but it will be very difficult to include the motor in the truck (as you said) without major modifications although the biggest issue would probably be implementing steering for a City scale vehicle.

Also relevant: How can I motorize City-scale wheels?


text:
Lego Technic 42048 with LEGO 8293
I have seen a YouTube Video that claims the motorization of LEGO Technic 42048 using LEGO 8293. However, the LEGO support site does not state such compatibility.
I am not able to get my hands on a physical box of 42048 to see whether the power functions symbol is on it.
Appreciate if anyone could share whether LEGO Technic 42048 can be motorized with LEGO 8293 straightaway, or if there are any special tweaks or pieces required?

Well the thing with LEGO, (Technic, Classic, Mindstorms or whichever category you talk about) is that it is customizable. You might not get instructions to combine Power Functions with this kit but you can figure out a way or look at other people who have done it. No, you cannot straightaway attach Power Functions with the 42048 set. There are sets (at higher prices) which have been designed to contain the PF elements. So no the power functions symbol is not there on the 42048 box.
However I encourage you to go ahead and try to attach the 8293 PF elements to any Technic set you have since you probably can fit the parts into most sets.


text:
What does taking Raw value for EV3 Colour sensor do?
I participate in Robotics competitions like the WRO and I want to know if using EV3 colour sensor raw values helps in line follow.

When you take a Raw value from any sensor, the EV3 brick passes on the reading as reported directly from the sensor, without doing any processing. Especially for the color sensor, where you have several modes such as Reflection and Color Number, the EV3 brain does do post-processing on the input value to make the output easier to understand and/or use. By getting the raw value you are likely get a higher resolution signal than in any of the other modes, at the expense of potential error correction.

As for the range? What values does it give,  from 0-100 or is it 0-255 or something else?

It will from 1 to 255. Now I try to measure color via RGB value to make the rank higher than using color sensor value block.


text:
What are these strange black disc LEGO pieces?
What are these discs? Ammo maybe or ice hockey pucks? I did not find any id numbers.

That would be Sports Hockey Puck, Large:

It comes from the larger Technic-based Sports Hockey sets from 2003-2004.

(Puck in the above set has stickers.)


text:
Is there a way to buy just the robotic parts?
I apologize if this is a silly question.  My kids recently went to a LEGO robotics workshop at our local science museum and LOVED it.
Is there a way to buy just the robotic parts (motor, sensors, software, etc)?  We don't need anymore lego bricks, as we have them coming out our ears, lol.
I did see parts on ebay, but got overwhelmed since I really don't know about the different types and what is compatible. Is there a good place to learn about that?

Yes, you can buy all the electronic parts by themselves, but given that the electronic parts are the bulk of the cost, you may not save much.
The MINDSTORMS EV3 set (MSRP $349.99 USD) contains:

1 - EV3 Intelligent Brick (MSRP $189.99 USD)
1 - EV3 Color Sensor (MSRP $39.99 USD)
1 - EV3 Infrared Sensor (MSRP $29.99 USD)
1 - EV3 Touch Sensor (MSRP $19.99 USD)
1 - EV3 Cable Pack (MSRP $14.99 USD)
2 - EV3 Large Servo Motor (MSRP $24.99 USD each)
1 - EV3 Medium Servo Motor (MSRP $19.99 USD)
1 - EV3 Infrared Beacon (MSRP $29.99 USD)
Software: Free download.

That comes to a total of: $394.91, or $44.92 over the price of the whole kit.
That means you would have to find these pieces for a fair bit less than the MSRP to save any money (remember shipping costs if you get them from multiple sellers), which could be difficult as these pieces tend to have good resale value. At quick glance on BrickLink, I found you can maybe get $40 of an EV3 Intelligent Brick, but the EV3 Medium Servo Motor is actually selling over the MSRP (possibly because it is backordered).

We don't need anymore lego bricks

The Mindstorms kits actually come with LEGO Technic pieces, not bricks. You would not really be able to use these electronic parts without a fair number of Technic pieces.
If you plan to follow along with the instructions from the kit, you would need to have the parts in the kit.

OK, that makes sense.  The kits they used at the workshop were apparently much more basic.   They were some kind of educational kit that just had a motor, tilt sensor, motion sensor, and various Lego pieces.
Would you say you can build things other than what the instructions show with the EV3 set? My older son hates instructions and almost always builds his own thing.

@BeckyBrown Sounds like you might be describing LEGO Education WeDo. I don't know if LEGO limits who can buy them, but they are also available on BrickLink. Both MindStorms and WeDo can certainly be built into other things besides what the instructions say.

It could also be the new LEGO Boost sets - the software is available from the App Stores, but I don't know if the logic brick is available on its own yet.

There's also EV3 education set, that has several more sensors (and lacks the remote) compared to the EV3 retail set. The education set is actually better value for money if you have already some LEGO at home, as it gives you more robot parts and a lithium battery.


text:
Why are there 4 wires leading to the Power Functions LEGO train motor?
Does anyone know what the wires do?
If the Power Functions train motors are simple DC only 2 wires would be needed or is it more complex than that?

The LEGO Power Functions connectors have 4 standard designations regardless of the usage:

9V power
"0V" Ground
C1 "control 1"
C2 "control 2"

It seems for motors that the 9V and Ground are unused.  The C1 and C2 are used in combination to pick the motor direction.  If C1 is providing power and C2 is providing ground then the motor goes forward.  If C2 is providing power and C1 is ground then it goes backwards.

The dashed lines are unused at that stage in the flow.

To drive two motors in opposite directions at the same time from one output of the remote unit all I need to do is to reverse C1 and C2 on one of the connectors?

That sounds reasonable.

If you're using the standard battery box, and no remote, that is the difference between the two on switch positions

It's strange that they chose to do the reversal by adding 2 more lines rather than just reversing the polarity of the power. It means there has to be logic in the motors as well as any switches you add to the chain.


text:
Building a more-efficient water propeller?
I enjoy making Power Functions-controlled boats to race (in water) in various LEGO convention competitions (which require 100% genuine LEGO pieces).
Usually, these boats end up being paddle boats, because of how inefficient all the LEGO propellers are. Supposedly Propeller 2 Blade Twisted (4745) is actually the most-efficiently shaped LEGO water propeller.

There are a number of problems with this propeller.

The blade are thick.
There is no good way to attack an axle to it.
The shape of the blades is sub-optimal.
It's on the small side.

Is there a way to build a more-efficient one, out of several pieces?

The LEGO RC boat by Slewentogzz claims to have a top speed of 3 km/h, it uses a custom propellor built out of Technic parts.
The actual rudder parts appear to be Technic Panels #87080 and #87086. These panels are very common and are available in over 60 sets.
There are two more parts in a similar design (#64683 and #64391, they are one stud longer each so you can make a slightly larger propellor.

Images: Slewentogzz Lego Creations
Video: "Lego RC Boat with custom built propeller (3,0 km/h!)"

I've tried the propeller. Unfortunately, I found it still under-performs paddle wheel designs. Not a bad suggestion for an alternative propeller design though!

In theory, I don't think a paddle wheel can be as efficient as a propellor.

Yeah, that's my understanding too... But in practice LEGO doesn't make a proper water propeller.

@Ambo100, a properly shaped propeller is far more efficient than a paddle wheel because it takes advantage of hydrodynamic lift rather than merely direct displacement of the water.  The hard part is getting the shape right  -- if you don't have the right curves to produce lift, you're wasting most of your energy just churning the water.

Rather than making your own propeller with piece- which might break under the stress of water- i recommend using a different propeller like:

https://www.brickowl.com/catalog/lego-black-propeller-with-3-blades-5-diameter-92842
https://www.brickowl.com/catalog/lego-propellor-2-blade-9-diameter-2952

More propellers:
https://www.brickowl.com/catalog/lego-parts/vehicle/propeller

As far as I can tell, and according to my one link, these propellers are actually worse than the yellow one pictured due to how small the blades are and how shallow the blade are pitched.