text:
Parts for "Simple Machine" book by Isogawa-san?
I would like to make some models from The LEGO Technic Idea Book: Simple Machine by Yoshihito Isogawa.
It seems the author is using parts of different "Technic" sets.
Could you advise where can I get parts (or ideally a set) to make the models for the book?

so cool, I did not know that Isogawa wrote books, his youtube films are so much fun and his usage of lego bricks is highly innovative. I will order one book now, thanx for the info.

It is a truly excellent series of books.  These are the most elegant of all of the LEGO books I've ever seen.

There was a lot there, but the very last sentence from your Amazon link mentions to visit the No Starch Press website for a list of the special parts used in the book.
There the website includes all three books from the author's
 LEGO Technic series:

The LEGO Technic Idea Book: Simple Machines. (Digital PDF of book here.)
The LEGO Technic Idea Book: Wheeled Wonders.
The LEGO Technic Idea Book: Fantastic Contraptions.

All with a few set recommendations directly from the author, where he suggests sets that have a wide range of parts in single set purchases.
For parts left over, he offers a reference list with colored pictures of each part, and purchasing links to Bricklink.com.

As far as I know Isogawa uses a large range of colored bricks to show the mechanisms. There is no single real set you can buy that contains all the parts. If you really need to have the exact same colored bricks you would need to look into buying them separately. However this might get a little tedious or expensive. Any other bricks in common colors would work nicely as well.
There are many ways of buying the needed bricks separately. You may wish to check Bricklink, Brickowl or LEGO Pick-a-Brick selection.

www.bricklink.com is a great place to find parts!


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Is this black and red speedboat model from an official set or a MOC?

Please help me: is this from an official set or an MOC?

This is part of 6679-1: Dark Shark

perfect, thanx Syberion!

source: Stack Exchange

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

sort: votes


text:
What is this old dark grey LEGO wedge piece with a grooved handle?
Here is an odd piece that I have found - any idea what it is? 2x2 plate is shown for scale.

It's a LEGO brick Separator tool. Mostly used to preserve the structural integrity of the human nail, teeth, gum line etc...
Watch the classical use of it here.

Here's a recent post of some unorthodox uses of the Separator tool.

To expand on a previous answer, it is the original brick separator that was produced between 1996 and 2011 in two colors. It was replaced in 2012 by a different part with the same name and purpose but slightly different features.

It is always orange, but one of the only sets which have the part in a different color is 80013. I just noticed right now.

@mindstormsboi You might want to clarify your comment. First of all, my answer is to the question about what the part in the question's image is, which is the original brick separator which does NOT come in orange.Second, your comment both says that the new separator is always in orange and also that it comes in a second color. Both statements can not be true. :-)

Yeah, you're right, and besides that I've already found some other sets that have this piece in a different color. But it doesn't matter.

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


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Is there a Ubuntu Linux LEGO instruction manual creator?
Is there a good LEGO instructions manual creator for Ubuntu? I can't seem to find one.
Also, are there any online ones?

Hi @Redblackva and welcome to Bricks. It would be great if you could add any details of any programs you've already tried, and what didn't work for you so that we can (hopefully) suggest some alternatives.

LeoCAD is available for Linux based OSs as well as Windows and Mac, and supports Step creation as well as general model creation.
There are a few other workflows detailed in this answer to a similar question.

In case you have made your model with LDraw based software with all necessary steps already you can use LPub3d to create building instructions. There is a bit of a learning curve to make your instructions look right with required features. But then it makes them look almost like made by LEGO.
There is even an Ubuntu native *.deb package available to download. No need to compile from source.


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Where to buy rare old LEGO sets?
Does anybody know a good place to buy rare old LEGO sets?
I'm looking specifically for old "pneumatic" featured LEGO Technic sets.

I'd try bricklink

search on Bricklink.com for the keyword "pneumatic". there you will get approx 40 different sets and their set-number. then seach on ebay for "lego + set number" , there is a lot to find. good luck and enjoy...

If you already have a specific set in mind BrickSet provides links to ebay, bricklink, etc. to get a good overall idea of what prices look like.  BrickSet also has a tag for pneumatic sets.  I use it for tracking my wish list and what I already have.
I usually end up buying the sets or parts on BrickLink, but I'm not shopping for old sets that often.  There is much less sketchy stuff happening in BrickLink than on ebay.  You can find better prices if you're patient with ebay, but the BrickLink prices are often totally reasonable.  BrickLink also functions as the canonical list of sets and which parts are in which sets.  Sites like BrickSet automatically synchronize with it.
Looking at one of the oldest pneumatic sets - 8851 Excavator - ebay has it for $12 & $12.99.  BrickLink's prices start at at $39.67 so I'd probably see if the ebay seller's have high-enough ebay reputation to deal with.  In this case ebay might even require less patience than bricklink.

Thanks for your response, it's very useful :)


text:
What is this 2×8 plate slotted, rectangular studs and a hole in the middle?
Please help to identify this part. What is its use?

This is
Part # 767 : Train, Track Sleeper Plate 2 x 8 without Cable Grooves
or
Part# 4166 : Train, Track Sleeper Plate 2 x 8 with Cable Grooves
depending on the cable grooves.
It is used  to attach train tracks

You can see the cable grooves in the image.


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Is this red axel bushing an original Lego part?
Is this an original Lego part? Technic maybe?

This is
Part# x1299 : Technic Bush Old 1

ahh, early 70s, first time that I saw one of those, thanx!


text:
Please help to identify the set this sticker belongs to
Please help to identify the set this sticker belongs to.
The sticker is on both sides of the ensemble.

Bricklink lists this as a sticker over assembly
Part # BA55pb01 : Stickered Assembly 4 x 1 x 2 with Arctic Technic Logo Pattern on Both Sides (Stickers) - Set 8640 - 2 Slopes 45 2 x 1, 1 Slope, Inverted 45 2 x 1
From
8640-1: Polar Copter


text:
Is this black two-sided clip an original part made by LEGO?
Is this an original LEGO part? Maybe Technic? See the cup for size comparison.

The black one is a playmobil part, used to link fort wall part together. I think the cup is playmobil too.

the playmobil origin is absolutely possible. i bought this in a used bulk on ebay. thanx for the answer. but now i wonder if playmobil stole the cup design or vice versa? ;-)

To see if the cup is genuine LEGO or not, look for the "LEGO" logo and the part ID hidden somewhere, like on the bottom, on the inside, on the end or the inside of the handle.

I don't recognize this part as produced by LEGO. On another thought, pictured black part has rough edges (low quality), which is unheard for LEGO.

yep, the quality argument makes totally sense


text:
Cleaning Bricklink pieces bought as "new"
I'm just preparing my first Bricklink order and I've got a simple question - Is there a reason to clean pieces bought on Bricklink which were sold as "new"?

Pieces sold as new are directly pulled from brand new LEGO sets, or from the Pick-A-Brick wall. I don't see what would be the point of cleaning them. They are as new as new and clean as they can get.

@TheBrickBlogger: To be fair, pieces from the PAB wall that have been in there for a long time may well be as good as used, thanks to dozens or possibly hundreds of hands rummaging through them, dust, shelf wear and all that. I can no longer guarantee pieces on the PAB wall to be new - it seems to be a crapshoot these days unless I keep track of what's been on a particular wall and what's recently changed.

No. 10 out of 10 orders were in perfect condition. Cleaning the bricks would have been a waste of time, and would have added unneccessary scratches.


text:
What is a good third party battery box and receiver?
I got the LEGO 4x4 crawler for my birthday and I love it. But there is one slight thing which I hate: it has terrible range when using it outside. I know there is BuWizz which is a third party receiver but it can only be used with a phone. So I can’t use that, because the whole reason why I got the 4x4 crawler was to get me off of my iPad. Does anyone know a 3rd party remote, receiver or battery box?
I’m 12 and unable to do any electronic modifications, like using tools and modifying electric components.

As you have mentioned, there is BuWizz and SBrick which, while primarily are intended to work with smartphones, are said to be able to work with joysticks or gamepads, albeit possibly with bugs.
I don't really see why would your age mean that you can't do modding, but assuming you have budget restrains or parents who would not allow it then these are valid reasons. Anyways, I'm sure you have your own reasons, just don't underestimate your abilities just because of your age.
There is of course the new Powered Up system from Lego, on the right side of this image you'll see the controller and the motors currently in use:

Drawback: There are no servo motors available for it yet, so you can't fully control the 4x4 crawler without extensive modifications to either

use a second motor for steering or
settle for a tank-style drive with a separate channel and motor for the left and right wheels.

Another third party solution I have managed to find is the CADA controller. The main selling point is exactly what you are asking for:

The most interesting feature is indeed dedicated controller, unlike buwizz/sbrick there is no need for smart phone.

According to one reviewer:

The range is limited to 10-12 meters

so it should yield better results as the PF infrared remote.

Any touch screen device has a huge disadvantage - lack of touch feedback. You don't feel if you already moved your fingers out of switch control zone. And you don't know how much you need to moves fingers back to make a counter movement. This is not to mention inability to locate (another) control buttons.

While CADA looks promising, it has small capacity battery, which won't last long, espeacially with a crawler.

Note that there is also the PfxBrick as a thrid party option.

The original question asked about complete turnkey systems, without "any electronic modifications, like using tools and modifying electric components", for which the other answer provides solutions. This is the answer for all other possibilities, as prompted by Aziraphale:

It might be that third party producers provide remote controls ready for implementation in LEGO sets. We see the same for lighting systems that contain LEDs, batteries, ultra-thin wires etc. I would also accept non-professional custom solutions that allow usage of non-LEGO parts in my sets, possibly by showing how to glue/connect non-LEGO equipment to LEGO bricks.

Disclaimer: I have neither authored, nor tested any of these ideas, but I have reviewed them all and deemed them useful and correct. The information contained them might nonetheless be incorrect, outdated or unusable for any other reasons.
The simplest option would be to extend the range of the existing receiver by increasing the power emitted by the IR remote control, by using a custom IR transmitter:

A fully LEGO compatible DIY electronics project is authored by w4ilun and uses a Toshiba motor controller embedded in a custom-designed printed circuit board to interface with cut and repurposed PF cables:
If we are willing to forego LEGO Power Function motors as well, we can use any kind of DC motor we can build a LEGO compatible enclosure for. This project uses the radio control parts salvaged from a toy car to integrate them into a LEGO chassis:
Or an existing 2.4 GHz remote can be used with this custom designed receiver:

Thank you for expanding the scope of your answer. This is the type of things that I would like to see. Not only to improve the LEGO electronics solutions, but also to be able to do things with LEGO that had not been possible at all.

Thanks for the bounty, even though I feel neither I nor this answer deserves it. I have just searched for these solutions, and compiled a link-only answer which is usually frowned upon. But I can't copy the contents over here either as it would amount to copyright infringement. I think I should thus ask the Meta community about this as soon as I find the time for it.

I disagree. Even if most of the information is too much for my little electronics skills, some of it is useful for me  (e.g. custom motor housing ). If some other forum get something out of it, then it is worth the points.


text:
How can I get this broken part out?

My New LEGO minifig has a broken hand because of me. How can I get this broken part out?

some days ago successfully I used a hot needle which was glued/welded into the rest of the hand. you can then pull it out carefully


text:
What are these grey scoop-shaped parts with a hole for an axle?
I got these in a lot that I bought and I have no idea how to identify them. They have dates from 05 and 02, but no part numbers.

Pretty sure they are dinosaur pieces. Should be under animal parts on bricklink

This is:
Part# 42042 : Light Gray Bionicle Krana Holder 3 x 4
Keyword: 3 x 4, Color: Light Gray
it appears in 13 sets

Hi @Yankees27 - welcome to Bricks! If this has answered your question, it would be great if you could click on the tick to the left - this lets people know that your question has been answered, and gives both you and Syberion some reputation ;)


text:
What do I need to connect an old RCX 2.0 to a computer and is it worth compared to just buying a new one?
From a friend I got some Lego, including an old Mindstorms package (RCX 2.0 as I already found out). It's my first time with the Mindstorms "eco system".
I already found out that I need some kind of IR sender for the connection to a computer -- sadly, the original one is missing. Now I'm trying to find out what I actually need to be able to do something with the whole stuff and if it's worth at all to put a lot of effort into it (or if it'd be easier/cheaper to just buy an up-to-date Mindstorms package).

what IR sender should I buy (I saw that the original ones are available for cheap, but if possible I'd like to buy up-to-date or more generic hardware that I can also use with newer Lego systems or ideally also non-Lego "endpoints")
What software do I need in general?
Are drivers (if needed at all) still compatible with up-to-date computer systems?
Do I need some kind of firmware updates for anything?
are the downloads on lego.com (https://www.lego.com/mindstorms/downloads) compatible with RCX?

I'm having access to computers running Windows 10 and Ubuntu (both 64 Bit) if that matters.

Modern hardware/driver support for the RIS is limited, but it's definitely possible to get it working again.
The main obstacle is transmitting programs to the Lego RCX brick. The RIS 2.0 came with a USB IR Tower, but the driver does not work on 64-bit Windows. There is also a Serial-port IR Tower available, which works perfectly if you have a 9-pin serial-to-USB adapter.
Here's what you need to buy (they're all very cheap):

A serial cable (not necessarily a Lego one, any 9-pin serial cable will do)
A Lego serial IR tower (can probably find on Ebay as well)
A USB-to-Serial converter (not necessarily this brand, any basic 9-pin serial to USB should work)
A 9V battery for the serial IR tower.

With the (included) driver installed, the USB-to-Serial will create a virtual COM port in Windows. If it's relevant to you, you can check the number of the COM port in windows Device Manager.
On the software side of things, you can code for the RCX using Java, NQC (C-like syntax, but much simpler), or the original Lego graphical programming language. You don't need to install any Lego software if you plan on going with one of the 3rd-party Java or NQC options.
If you do want the Lego programming software but you don't have the disk, you can download an ISO disk image from this guy's share. The Lego software and its installer ran fine on my machine (64-bit Windows 10), with a small caveat: At the end of the installation process, it attempts to install the USB tower driver. When this happens, you need to go to task manager and KILL the installer process, because when the driver (inevitably) fails the whole installation rolls back. If you're having trouble it might also help to right click on the Setup.exe -> Properties -> Compatibility and run it in compatibility mode for Windows 98.
Inside the Lego software, you should select the Serial IR Tower when prompted because you want it to use the virtual COM port the adapter provides. You can also set the COM port in the Settings from the main menu screen.
When you first install the software it will try to force you to do tutorials before you can actually do the "freestyle" programming. But you can double-click any greyed-out option to enable it.
And as always, if you need more help you can always post back here in Bricks SE. Good luck!

The USB Tower also works on Linux as does much of the 3rd party software, like NQC.

@DavidLechner That is correct, but as of Ubuntu 18.04 NQC requires several layers of patches to get it to talk to the tower properly (and some of those patches don't work without manual modifications). Definitely an option, but IMO much less accessible.


text:
Please Help Identify These Star Wars Sets
I guess these are StarWars sets, please help to identify

1.Set# 75172 Y-Wing Starfighter.
2.Set# 75013 Umbaran MHC (Mobile Heavy Cannon).
3.Set# 75003 A-Wing Starfighter.
(Note: Canopy and gun turret on KETCHUP colored ship belongs on MUSTARD colored ship.)
See ya Fabian!


text:
Is it possible to sand/polish LEGO bricks?
I have an old white and rare brick which got scratches and dirtying which I cannot wash away. Any ideas on how to clean it? I thought about fine sanding or polishing but I am afraid that I damage the brick.

Sanding it, even with melamine, will remove material and change the perfect fit of the brick. I'd try looking up how to rewhiten the bricks with hydrogen peroxide mixture, it takes a few days, but it may well be worth it.

yep, did it already before posting my question. still, the situation is unsatisfying

It is definitely possible, since ABS is a plastic that can be either mechanically or chemically affected. Cleaning bricks is a well-studied field, you will find useful information regarding this topic all over the internet, including here.
Polishing LEGO bricks is less heard of, but can be done either mechanically (another link) or chemically (another link). Note though, that any kind of polishing includes either removal or rearrangement of material, so the chance of damage is definitely not zero in any method. I'd suggest starting with the gentle and precise methods (file, hobby knife, fine sandpaper, etc), and only progressing to more drastical methods (acetone) if they fail.
When using acetone, be especially careful, as the vapours can't be easily controlled, and they are flammable (can burn down your house), poisonous (can kill you and your family), and can even melt the entire brick if given the chance! Of course the dangers depend on the amount and ventilation, but some of the above links depict clearly dangerous settings, uses and amounts.

I will add to this one more method that is often used for removing print from minifigs and other parts: Brasso (the copper polish). Brasso is abrasive, but it is much finer than sandpaper. So, when you rub it over a LEGO element with a piece of cloth, it will work like sandpaper. However, because Brasso is so fine, you won't see any scratch marks like you would with normal sanding.

thank you guys for your detailed and very helpful answers

From Brickset forum: If you have a badly scratched part (especially a flat part), rub it on a flat absorbent surface that has dilute acetone on it, and you get rid of the scratches. It does leave it slightly shiny as you uncover the surface, but often better than the original scratched surface.


text:
135149 is all info I have
My son got some LEGO bricks in a bag as a present from good will, but no instructions were included. The only info I have are numbers on the bag 135149 and 2011. One of the small pieces has 62361. But no luck to have any info with numbers.

The numbers on the bags don't give us much to go on.  Can you add a picture or two?

People on this stack can literally identify a set from a picture of the parts. It's crazy. But you should post a picture so they can work their magic.

2011 is probably just the year the bag was copyrighted, not anything useable to go on.
The other number on the bag is not really useable either.
Part 62361 is Vehicle, Mudguard 1 1/2 x 6 x 1 with Arch a part that has been in 98 sets. There are probably numbers on most other parts in the bag too, but pictures are usually better.


text:
Help identifying set from 3 sealed bags with Star Wars figs
I got these three bags in a lot. Looks like there are two snow troopers and bag 4 has a bunch of fluorescent green circle pieces. Any help would be appreciated for this first time poster.

Welcome to Bricks.SE! Based on the 10 x 3 Wedges and your description, these bags likely belong to 75100 First Order Snowspeeder:

The instructions for this set are available here:
https://www.lego.com/biassets/bi/6136428.pdf


text:
Where's the iNXTG app for programming NXT from iPad?
I'm trying to find the old iNXTG to program NXT bricks via iPad but it is no longer available in the Apple Store. Does anyone know if there exists an archive for programs like that?
The problem is that the new LEGO programmer for EV3 does not recognize the NXT brick with Bluetooth or a USB connection. We have no laptops in school, just iPads and Chromebooks.
Does anyone know of an NXTG version that would run on iPads or Chromebooks?

Unfortunately there is no good solution for controlling NXT’s from an iPad. There are plenty of Android apps to control them manually, but you’re best bet on iOS is to write something on your own. LEGO does provide a Bluetooth Developer Kit with the info so it is possible.


text:
Has LEGO Made A Minifigure-Scale Shopping Cart Piece?
For the current MOC I am working on, I am going to need a LEGO Minifigure-scale shopping cart. I thought I had seen one in an official set, but after searching Bricklink extensively, I am now not sure they have. Has LEGO produced a shopping cart piece or will I just have to make my own?

There is one Friends scale shopping cart. But that is probably not helpful I guess.

@Aziraphale why not?

@Aziraphale On the contrary, that is actually quite helpful!

The 41118 Heartlake Supermarket contains a Friends scale shopping cart. This is how it looks like:

There is, however, a cute little MOC design with Window 1 x 2 x 2 2/3 Pane Lattice Diamond with Rounded Top on both sides and 1x2 tile modified grilles. This is, I think, a perfect shopping cart:

@MindS1 This is how far I got with it. The panes bend the grilles quite a bit. I would consider this an illegal building technique. I also don't see how the droid arms connect to the wheels and to the basket part.

The Friends shopping cart is most likely the one I've seen before. That design is perfect! I guess I'm finally going to be able to put my Lattice Windows to good use! :D

That is a really excellent design. It's so hard to find good solutions at that scale!
What is the minifigure holding onto in that picture? And how is it attached to the grille?

The grills are the other way around on the MOC...

LEGO heard the wishes, and finally put one out new this year (2019).

Part #49649 Minifigure, Utensil Shopping Cart Frame.
Part #2496 Wheel Skateboard / Trolley.
Is this for a Fortnite project?


text:
Is this an early Duplo mini figure?
Just wondering if you have ever seen this figure before?

I've had it since I was a kid in the early 80's, and it's always lived with my lego (which was mostly hand-me-downs from my older brother - ie Space #897 rocket set).  It doesn't fit with Lego, but does seem to fit with Duplo.
Looking at early Duplo mini figures, they look vaguely similar, however the Duplo figures are squared off, whereas this figure's body is circular.
There's no markings to indicate brand...
Just a little mystery in my life.  :)

I've just been scouring eBay... and as noted, the above is "similar" to the early Duplo figures, however when you look at the artwork on the faces... the eyes are completely different, and even the mouth is at an angle that I haven't seen on other Duplo... Has me thinking that this is a toy from something completely different, that just happen to look like it could fit on Duplo...

My first thought was Fisher-Price Little People, but they typically come with a different underside.

I saw them too during my search, but they all have a "step" down the body, whereas this is straight.  And yes - the bottom of my piece has 2 concentric rings; the inner ring fits (a little loosely; perhaps from age?) over a Duplo stud.  The outer ring fits quite well "over" 4 studs - the "cut out" sections falling neatly into place...

At last, I have your answer. The figure is from a "Giant Pre-School Loc Bloc" set, likely the "Playground" one shown in the picture.
Nearly a month later, while doing unrelated research, I found "Giant Brix Blox", a second possible source of these types of figures;

It makes since given that sources claim Loc Blocs & Brix Blox were both imported from the Japanese company Kawada.

I don't know how you did it, but well done and welcome to Bricks SE! I spent a good few hours trying to find this figure to no avail. I'm glad someone could finally solve this mystery!

Persistence. Once my curiosity is piqued I have a hard time letting it go.  Sometimes a blessing, often times a curse ;)

Well I commend you for that! :)


text:
What does the acronym SPUA stand for?
I once heard someone use the acronym SPUA while referring to a LEGO piece. What does that stand for and what does it mean?

Stackable Parts Utility Application, Series Premiere Under Association, Space Pirates Universe Aces, Small Pieces Utilization Accessory

@RobertColumbia You seem to be suffering from some severe case of overLEGOing

SPUA - Special Part Used Again, a part which is seemingly only for a particular set or theme, but is used again
List of LEGO Abbreviations from Brickipeda


text:
How can I separate an 8H antenna from a modified 1×1 with ring?
I have two parts which are stuck together:

4081b: Plate, modified 1×1 with clip light – thick ring
2569/25699/47094: Antenna whip 8H

The parts have been assembled like this for about 20 years and may have dust in between them. They have been cleaned with water and mild hand soap. They were stuck firmly before cleaning. Other instances of the same assembly were not so difficult to take apart.
I have tried gripping the antenna and pushing it through, prying my fingernail against the lip where the antenna gets thicker near the base, and prying between the base and the ring with fingernails. I've also tried flicking the tip of the antenna to try to knock it loose and twisting while holding the shaft, but it's really in there. Before I try prying with stronger tools that could gouge the parts, I wonder if anyone has any tricks for separating these parts.

Ah, yes. I have had this problem a few times. Here's what I do:

The first thing you're going to want is leverage. Connect one 1x6 plate to the underside of the Modified 1x1, one on top of the previous plate (but adjacent to the Modified 1x1), and one on top of both pieces.

Next, slide propeller piece 32125 over the tip of the antenna.

Hold the antenna upside-down (vertically), with the 1x6 assembly in your right hand. Move the propeller piece all the way up, but stop before it gets to the section the Modified 1x1 is on. Maneuver the antenna's stem into one of the four sides of the axle hole on the propeller piece, tilt it at an angle, and push up. There should be a slight pop and the 1x1 will move down the antenna.

Now that you have something to push on, simply remove the propeller, grab hold of the 1x6's with your right hand, and press into the base of the antenna with the propeller piece. It should pop out the rest of the way and then you're done!

Why does this work? Well, the propeller piece is perfect because it had a proper diameter to fit over the round tip, and the sides of the axle hole are a prefect dimension to hold the smaller thickness of the antenna stem, thus giving you a contact point for applying pressure. I suppose it's a bit over complicated, but it works for me. :)

This + I'd put a dip of soapy water into connection between two pieces.

@Alex Yep, that might help as well!

I was able to make this work without the propeller (since I don't have one and I didn't see this answer before getting the parts unstuck). The idea of bracing the 1x1 with other bricks seems to be essential, though. The propeller is a good idea to reduce the risk of bending the antenna and I recommend using it if you have it. If not, just use your fingers and be careful.

I fail to reproduce your problem. When I combine these parts, they are easily separable. Hence the following is an educated guess:

Put the antenna on a big plate on a table (for stabilisation).
Grab the antenna slightly above the clip with one hand and hold it tight.
Grab the clip with the other hand and push up, while turning it around the antenna’s axis.
If needed, use the rest of your hands to push down the plate for further stabilisation.

Thanks, I'll try it. You may have trouble reproducing the problem because you didn't leave the parts assembled for 20 years. :)

For completeness, I am posting the solution which ultimately worked for me. It is just Wrzlprmft's answer with extra parts to keep the 1x1 in place. It is also very similar to Magnus's answer, but without the propeller.
I surrounded the 1x1 with blocks on all sides so that it could not rotate or come off easily. Then I firmly gripped the antenna as close to the base as I could and pushed it through.


text:
Rearing off to the left without telling it to
I've started to build a robot, but when it drives it veers off to the left even though I'm just telling it to go straight. I think I need to do something to the motors but I don't know what or how. I'm programming an NXT block.

Hi Donna! Could you please tell (or even show) us more about your robot and its program? The best would be if you attached a photo of the robot and a screenshot of the program, but even a textual description would allow us to help you better.

Hi Zovits!
Here's the program:
task main()
{
TextOut(0,LCD_LINE1, "HELLO GENIE");
Wait(SEC_3);
OnFwd(OUT_AB, 30);
Wait(SEC_3);
}
But I don't know how to put the pictures in.

This page in the Help section describes how can one embed images: https://bricks.stackexchange.com/help/formatting
The program seems to be correct, and if assume that (1) the two drive motors are connected to the A and B ports and (2) use the same gearing to drive (3) wheels with the same diameters (4) with no mechanical blockages or friction then the robot should indeed go straight. Can you please verify these four assumptions?

Add picture to original post, as far as I know your assumptions are correct. However I did wondered if one of the motors could be running slightly slower then the other as in a text book I have says that you might have to sink them so they run identity?

If that is the case you could try using the OnFwdSync command to eliminate another possible source of the error.

Seems like your motors rotate at slightly different speeds. That is very normal, as no two motors are exactly alike.

Veering off a little bit is normal.  Can it be reduced?  Yes.  There are several possibilities to consider, one of which is the programming.  Put a pin in the hub of each wheel to serve as a marker, spin the wheels so the in the same position.  Write a program to go straight for 20 revolutions.  Hold the robot in the air, run the program, and examine the location of the pins.  The should match.  Differences can be programming issues, but more likely the position sensors in the motors.  Try switching swapping one motor and retrying the test.
More likely, putting the robot on the ground and running the program will show the pins match, but the robot veered.  Again, several possible causes, one likely cause is the friction on one side of the robot is greater.  Changing to a caster will reduce the friction and might help.  Another possibility is that the motors are a bit wobbly and allow the axles to bend so they do not match.  This can often be helped by adding a skirt on the outside of the robot to support the axles from the outside.


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Mystery 2x14 grey brick - cannot find instructions with this piece mentioned
I have a bunch of LEGO bricks from the years 1975 - 2016. There are a lot of obscure pieces in my collection, but this piece is so obscure that I have no idea what it goes to. If anyone can help it would be much appreciated.

btw i have found a second 1 they have a 1 and a 2 on the bottom

Does it have LEGO logo on the bottom?

yes, and they both have "a 1" and "a 2" on the inside.

This is item no 812

Train Level Crossing Center Rail Cap Insert
2 x 14 x 2/3

made for item no 813, the railroad crossing.

(source: bricklink)
It replaces the 12V straight insert (i.e. it closes the middle gap) when using a 4.5V train system.


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Can two Powered Up train motors be plugged into one hub
I have set #60198 and it comes with one Powered Up motor. I'm hauling many many cars and one motor isn't enough any more. I see there is a slot for "B" on the hub. Is it possible to plug in another train motor into B and have the train be powered by 2 motors?
Does it even help? Not sure if a second motor would just split the power between the two motors if it worked, or does it draw 2x the battery from the hub?

You can attach second train motor to B output. However it will be controlled independently from motor attached to output A. So you would need to control speed for each motor separately.
Speaking of traction. The key thing here is your train weight. You might consider putting another full battery box (unpowered) into train just to increase weight and get more friction between wheels and the track.

Another thing to consider is that LEGO train motors are not precisely calibrated to run at any particular speed (or at least used not to be), so two motors given the same amount of power might run at slightly different speeds. I have seen trains with several locomotives, each with their own PF motor, that seperated after a short time.

I've seen this with 9V trains. However PF2 trains seem to be running fine - tested during two day event without uncoupling. We even had a case of one motor power loss on one end and still had all train parts together. I'm thinking train motor-axle-wheel combination might cause additional friction between these pieces if not adjusted correctly.

Can you guys take a look at the link? is this the right part? it says Powered up but it also says 9v. I know 9v is the old system right? https://www.bricklink.com/v2/catalog/catalogitem.page?id=167303#T=S&C=11&O={%22color%22:11,%22loc%22:%22US%22,%22iconly%22:0}

Correct, that's the latest train motor for PowerUp (aka Power Functions 2.0) currently available.

If you know any programming, there are third party Boost/PoweredUp libraries you can use to control the train from a bluetooth-enabled computer. You can then write a program that takes input from the remote and powers both motors simultaneously.

The other motor came and it worked like a charm. It's pulling about 12 cars with no sweat. my 3 year old son doesn't care, but I'm real happy.


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How can I separate 1 x 1 round from boat mast base 4 x 4?
I have two pieces I cannot seem to separate. The parts in question are:

3062b: Brick, Round 1 x 1 Open Stud
6067: Black Boat Mast Section Base 4 x 4 x 1 2/3

The 1 x 1 is transparent in this case, in case that makes a difference (I think the plastic type is different for transparent pieces).
The center of the mast base fits snuggly inside the 1 x 1. The outer wall of the mast base blocks access to the bottom lip of the 1 x 1. There is a hole through the bottom of the mast base, but it's narrow enough that if I try to stick a 3957 antenna through it, the tip of the antenna doesn't catch the top lip on the inside of the 1 x 1 round. I tried pinching the top of the 1 x 1 and wiggling it, but it is too tight.
Separate:

Assembled:

Transparent pieces are made of a different plastic. As I recall, the transparent ones do have a tendency to stick harder, especially against other transparent pieces.

How about a straightened paperclip pushed through the hole in the mast from the bottom? You could put a small piece of paper in first so that it'll catch on the 1x1 on the way out.

Success. The paperclip catches the edge as expected. I had to try twice. I think the second push was from a different side.


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Has the building technique of Technic pins in a brick cylinder been used in an official set?
One of my favorite building techniques is to place a Technic pin into the anti-studs of a brick. This allows two bricks to attach bottom-to-bottom.

It's a pretty secure connection, but I'm not sure it was intended to be used this way. Has this building technique ever been used in an official LEGO set?

I'm not aware of this being used in any official sets, but I'm happy to be proven wrong. I can say that LEGO considers this to be an "illegal" connection. The Technic pins need room to spring back out and be "in click", or they can be permanently damaged by prolonged assembly. LEGO would not allow this connection to be used in a current set.
A Technic pin not "in click" was used back in 2002 in the Audi TT and led to part damage as well as this sort of connection being banned from sets:

No, LEGO did not intend to do that building method though I have to admit, It is a pretty cool technique. So far there haven’t been any sets like that but maybe in the future LEGO people will realize they can do that.

jncraton's answer shows why they will never do that.


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What is a color sensor and where do you get it?
I have an NXT but I don’t know how to make it detect colors, all it does is say “wait”. My set includes a light sensor but I heard some YouTube videos say there was a lego “color” sensor. Does LEGO sell this? Can some one tell me how to get it please?

Lego has made colour sensors for various robotics themes, including Boost, EV3, and NXT. NXT is pretty old so you'll need to head to a 3rd party website like Bricklink to buy one.

The Original Mindstorms NXT only came with the NXT Light Sensor. The NXT Light Sensor cannot detect colors, so this is most likely what you have. You can currently purchase the NXT Color Sensor from Bricklink.com for under $30.


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Using switch block with Hitechnic color block
Can I compare the Hitechnic block --> measure --> color output in a switch block? For example, if the Hitechnic color sensor is seeing black, then do something, else do another thing. If not, then how can I compare the values? The program I made takes the Hitechnic color sensor output and stores it in an array, so what I am trying to do is if the Hitechnic color sensor sees the same value (same color) stored at index 0 in the array do something. How can I accomplish this? (The Hitechnic color sensor stores different values in the array)

Hi mohammed! Although I'm not familiar with this particular brand of sensor, but based on your description you can already store the read value in an array. This means you have the value in hand and therefore can perform arbitrary arithmetic or logic on it, including comparing it to a given constant (the value received while the sensor sees something black) or seeing if the value is below or above a given level (what you would consider as black).
If you need more help please specify the problem you are facing. Providing the source code could also let us help you more effectively.

I would sure use your help . how can I contact you ?

As you seem to be unfamiliar with this site I'd recommend reading the Help section, accessible via the ? symbol in the upper right corner. In a nutshell: on this site people can ask their questions and other visitors to the site can answer them. None of us is obliged to do this, but we all do it to help the askers and to help anyone finding these questions later on. Therefore taking a discussion off-site is very much contrary to all our efforts here. You can either edit your question to incorporate any additional details or use the comment feature to do so.

oh ok . I would like to thank you for your help, your comment really cleared things up for me . but I would to ask one more question please .should I use a compare block that is set to equal to and has the first input set as the current sensor reading and the second input set as index 0 in the array and take the output and insert it in a switch block that is set to logic ?

also how can I use the hitechnic color sensor block with a loop . I want the robot to do something until the hitechnic color sensor sees one of the colors in the list . how can I make a list that has a bunch of colors so I can use it in the loop block


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EV3 Ultrasonic Sensor programm
How can I download the ultrasonic sensor and open it? I want to open it on a laptop running Windows 7. Which program must I download?


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Is there any rhyme or reason to the sizing of LEGO boxes?
Recently, I have noticed that there appears to be no rhyme or reason to the sizing of any given LEGO set box. For example, in the picture below, you can see three sets that have a similar amount of pieces, yet three completely different box sizes.

Why does this occur? Is there any rhyme or reason to the sizing of LEGO boxes?

This is marketing department wizardry.
From a pure engineering point of view, the closer to a perfect cube (or rather sphere) you are, the greater of internal volume you can enclose with the same amount of material.
What does this mean? By not making cube shaped lego boxes, Lego isn't trying to be as efficient as they can be when it comes to their box design. This costs them more in terms of packing materials, shipping container size, and store shelf capacity.
And yet, they are happy with this choice because the marketing department has determined that big pictures of sets on the front of the box attracts consumer's attention and results in greater sales. In a vacuum (say at a LEGO store), they could be any size and the packaging would not be competing with other products (cough, cough mega blocs), but in the real world both companies are in a arms race to catch the eyes of uninformed grandparents who don't exclusive buy LEGO for their grandkids. So big, wide box fronts are ideal. If LEGO could get around the other problems of cost, shipping, and shelf limitations, they would make every box set look like it contains a big screen tv.
The ratios of height and width are interesting, as they seem to dance around a ratio between 4:3 to 16:9. (I cannot think of too many sets that are taller than they are wide). Some will be due to the dictates of the set inside (baseplates or special pieces), but LEGO clearly favors a ratio that mimics TVs and monitors. This is probably because they can keep the box height constant but play with box width to accommodate bigger sets. This makes it so that stores don't have to do shelf resets all the time, or mix sets of differing heights.

The first set that came to mind as having a box that is taller than it is wide was the Disney castle (71040). But it's just the technicality of the orientation of the print on the box that brings it outside your range (I haven't actually calculated, but it looks quite normal).

If the box is too tall relative to the depth it falls over too easily. If you take a wide set and flip it on its side so it is a tall set, then to have it stand freely on the shelf you have to increase the depth and thus decrease the width/height/total surface area.

The size of the box seems to be theme specific.
It appears that they choose a specific box design for any given price range and then stick to that size for the rest of the theme. For example, in the pictures below, you can see same sized boxes used in the same themes.

There is definitely some crossover, but for the most part this holds true.

Magnus' answer doesn't explain why different themes have same sized boxes or same front area (but different depth). Also same set re-release can have different sized box (take Mini from Creator for example). So there doesn't seem to be a rule for that.
What I heard from TLG employee is that front area of the box is basically a marketing space. So TLG tend to adapt the size of this area to desired shelf space. There is certain levels where you can put each shelf, so each box must utilize all the given space without sacrifying advertisement value.
Layout of the sets you see in the shop is science, sort of. And TLG spend considerable effort to reach desired value. They even test new layouts in their employee shop at Billund.


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Looking for custom EV3 block to control LEDs independently
The EV3 brick has 2 LED sets, one on the left side of the button panel and one on the right.
Software such as python for ev3dev let's you control them both individually, the normal EV3-G LED block however only allows to set them both to the same value.
Has anybody created a custom block that I can import into EV3-G that allows me to control the left and right LEDs individually?

It is not possible to control the LEDs separately using the official EV3 firmware. You would have to modify the kernel drivers. You can only use the predefined patterns shown here.
ULONG     LEDPATTERNDATA[NO_OF_LEDS + 1][LEDPATTERNS] =
{ //  LED_BLACK   LED_GREEN   LED_RED    LED_ORANGE           LED_GREEN_FLASH                     LED_RED_FLASH                     LED_ORANGE_FLASH                      LED_GREEN_PULSE                       LED_RED_PULSE                      LED_ORANGE_PULSE
  {  0x00000000, 0x00000000, 0xFFFFFFFF, 0xFFFFFFFF, 0b00000000000000000000000000000000, 0b00000000000000000111110000011111, 0b00000000000000000111110000011111, 0b00000000000000000000000000000000, 0b00000000000000000000000001110111, 0b00000000000000000000000001110111 }, // RR
  {  0x00000000, 0xFFFFFFFF, 0x00000000, 0xFFFFFFFF, 0b00000000000000000111110000011111, 0b00000000000000000000000000000000, 0b00000000000000000111110000011111, 0b00000000000000000000000001110111, 0b00000000000000000000000000000000, 0b00000000000000000000000001110111 }, // RG
  {  0x00000000, 0x00000000, 0xFFFFFFFF, 0xFFFFFFFF, 0b00000000000000000000000000000000, 0b00000000000000000111110000011111, 0b00000000000000000111110000011111, 0b00000000000000000000000000000000, 0b00000000000000000000000001110111, 0b00000000000000000000000001110111 }, // LR
  {  0x00000000, 0xFFFFFFFF, 0x00000000, 0xFFFFFFFF, 0b00000000000000000111110000011111, 0b00000000000000000000000000000000, 0b00000000000000000111110000011111, 0b00000000000000000000000001110111, 0b00000000000000000000000000000000, 0b00000000000000000000000001110111 }, // LG
  { 0 }
};


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Identify this fire truck set?
Can anyone identify this fire truck set? I’d like to find the instructions before it gets taken apart.

6752-1: Fire Rescue

Instructions:

Book 1
Book 2
Book 3


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Lego track switch doesn't close properly
Just two weeks ago, my kid got a 60198 cargo train and we added a set of 60238 switching tracks. With two (out of three) switches we have the problem that the switch doesn't close properly anymore to perform the lane change (the position to go straight is fine). As you can see the movable rail part doesn't completely close against the fixed rail track, causing the wheels to miss the turn. The train either just goes straight (best case) or de-rails (worst-case).

Any idea what the cause is, and is there anything I can do to fix this? This happened with two different sets, bought about 5 months apart (but put in use at same time) with two different vendors across Europe, so I'd be surprised this to be a 'bad batch'. I've also tried reversing the locomotive to check it isn't because the wheels are misaligned, but both the powered and non-powered wheels give the same result. On first sight it looks like there is a spring in the switch which got stuck/compressed/..., but I have no idea how to open this without breaking the track.
The correct "go straight" switch position is:

I'd look at the underside of the switch, to see if there is any mechanical blockage of the moving parts.

Warning: LEGO pieces were harmed for this answer
How the switch works

So, how does it work then? Well, let's open it up!

The back plate is held into place by 14 pins. We'll carefully pry it open with a knife. Alternatively, we could use a drill bit to slowly scrape off the pinheads.
Both methods are destructive. The back plate needs to be glued back on later.
Once we can lift off the backplate, we already got the slider.
Next we'll unplug the switch. Let's take a pair of pliers and carefully -just a bit!- squeeze the peg, then push it out.

Yellow: The slider is of a soft plastic. Notice the oval hole with a nose. When you move the slider this bit gets squeezed and then snaps into position. There's two stops, they have a figure 8 shape.
Red: At the end of the slider there's a single tooth. This tooth flicks
the switch.
Green: The switch has a peg and a spring. The spring has two legs.
The tooth    is supposed to sit right between them.

What's next?
So much for starters. Now, what about your points?
In any case, use some compressed air first. Switch them repeatedly. Maybe it's just a grain of dust. Still not functioning properly? Can you still return them?
Okay. Let's triple troubleshoot:

Is the slider stuck?
Can it move freely? Does it 'snap in'?
Does the spring have enough tension?

If the slider's malfunctioning, you'd have to remove the back plate. However, if the spring's your suspect there's a less destructive way.
How to access the peg only

In theory, one could try to pry out the switch with a flat
screwdriver. I didn't dare it. Parts could warp, the peg could break
and I think LEGO did their best to prevent creative kids from doing
it.

But take a look at the back plate. You can barely see it, but there's a circle. It's right on top of the peg.

I took a drill bit and started to slowly scratch off some of the plastic. Once the tip was through, I finished off the rest with a scalpel.
Take your time! The plastic is quite thin and the peg's right under it.
I could now easily access the peg with my pliers and push it out. I adjusted the spring and lined everything up.
How to access the spring
This might also work, but I don't recommend it. I gave it a try. It's way too fiddly.

Take a scalpel and cut a hole in the side of the switch.
Now you can take a peek inside. See if the tooth is off-center. If so, try to lift the corresponding leg of the spring with a needle. Good luck.

Wow, that is a thorough analysis, illustrated with great pictures and, combined with the sacrifice of the switch, the upvote is more than deserved!

@zovits Thanks! Now that we know the hidden parts and how they work, somebody might come up with a less invasive (i.e. destructive) idea. After all, how pointless are points that aren't switching...!

Okay, this post is closing in 2 years old, but I have found it looking for a solution to my problem, so others may find it too. I found out two important things:

You don't need to cut or drill the switch to get to the offending spring. You can lift the pivot peg out getting at it from the top.
If the spring is FUBAR or missing, you can actually 3D print it.
Full story here: https://www.biasedlogic.com/index.php/fixing-lego-railroad-switches/


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MindSqualls - can I connect more than one NXT brick using USB?
To access my NXT brick connected via USB with the MindSqualls library, I do the following:
var brick = new McNxtBrick(NxtCommLinkType.USB, 0);

The 0 is serialPortNr. If I were to buy a second NXT kit, would it be possible to connect it in a similar way (e.g. by setting the second parameter to 1)? Or can only one brick be connected at a time?

I’ve had a quick look through the MindSqualls code and it looks like you can. I cannot test this however as I don’t have two kits.
Note: I believe it is preferred to NxtBrick class rather than McNxtBrick class as the latter is for a special program used for precise control over the NXT motors.


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What is this part?
I found about a dozen of these in a mixed bunch of LEGO. Are they actual LEGO pieces or another brand? They are actually white, the pink color is a lighting error.

This is part 42446 or 28974; Minifigure, Neck Bracket with Back Stud.


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Why are the Lego boxes so unnecessary big?
I ask myself often when buying Lego why the boxes are so much bigger than the space that is needed for the contained content. It seems a waste in terms of material and logistics. I do store the boxes and especially the bigger sets needs lot of space in my appartment. I would be happy to have them smaller.

The possible reasons include:

Surface area needed for legal info, practical requirements like barcodes, information, feature descriptions and artwork
Aspect ratio of the artwork means the boxes can't be too long and thin
Leaving space between the bricks so they don't get squished up against each other
Size of the instruction manual or sticker sheet
Psychological tool to increase the perceived value of the set
Larger boxes grab the attention of the consumer better
Larger packages are harder to steal

But the exact reason is likely a combination of some of the above ones and maybe some others, most probably in a top-secret ratio known only by LEGO.

For the psychological reason, I've heard LEGO employees say it was about bringing the perceived value on par with the perceived value of competing products.


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What is the fastest way to estimate the number of pieces in a large collection?
I have a relatively large LEGO collection and I would like to know roughly how many pieces I have; however, it would not be worth my time to count each piece individually. Is there a faster way to estimate the number of pieces? Is there is a way to tell by their weight?

what's the "known number of parts/ unknown number of parts" ratio of your collection? do you mainly own lego SETS, do you frequently mailorder individual PARTS, do you even buy BULK by weight?

I own a good deal of sets (maybe 5% of my total collection), but the majority of my collection is pieces. I'd say I buy from Bricklink monthly, and I have not yet bought bulk by weight.

i'm not too familiar with bricklink, but i think you can download a list of purchased items. since you bought the majority of your collection there, the data in that list should tell you what some roughly 95% of your inventory are in numbers...

Hmm... Well, even if that were possible on Bricklink (which it might be, I haven't checked), that would still only cover about another 20% of my collection, as a lot of my parts are from disassembled sets.

If you have just sets (without additional loose bricks) it might be easier to add all of theese sets to your collection on Rebrickable. It will then give you more details, like number of parts, estimate value, etc.

@Alex That's a good suggestion. I think I'll do that with the sets I have.

What a tricky (bricky!) question.
Let's estimate...
By Weight
So, can one estimate the number of bricks in a bag or box by weight?
In fact, they do weigh bags and boxes over at the factory to make sure there aren't any parts missing. But of course they're just comparing expected weights.

That's why you can't simply weigh a big mix of unknown bricks to
calculate their number. There's no reference.

However, you can use a scale to estimate a number of bricks, if you have sorted them out individually.
If you keep your pieces in trays or drawers and you have a big bin of identical pieces (2x4's, 2x1's, ...), you can estimate them by weighing them.

Weigh them all, then divide by the weight of a single one.

Gets close. Speeds things up.

By Numbers
Anyway, try to narrow things down. To do so, collect as much data as possible.

Which sets do you own?
Look up the number of pieces per set.
Take into account if you bought an incomplete set. How much is missing?
Did you mailorder pieces?
Can you estimate the amount? Maybe check your orders/ accounts.
Did you buy a considerable number of bulk?

All this should already give you a rough number, considering the sets/mailorder/bulk ratio.

By Eye

Do you sort out your Lego into trays and drawers? You could count some of them, calculate an average amount and project it.
What about the relevance of certain parts? Do they count? Where there's lego technic, there's plenty of technic pins. You could simply leave out those piles of pins and separators or
weigh them. If they're sorted out, of course.

(Disclaimer: Do not take this last part too seriously...)
Or is it all in ONE BIG BIN?
Well, let's see.

How can one estimate the number of people in a crowd?

Take an aerial view, divide it into sections, count people in one frame and multiply by frames. As long as people are spread out evenly, you should get close enough.

Example: There are (maybe) 63 minifigs in this picture. Count all minifigs in one of the frames and multiply them by four for a rough answer.

How can one estimate the number of jellybeans in a jar?

Find out about jar and jellybeans, diameter, height, volume. Calculate. As long as you're not getting peckish, you should win big.

Now, how can one estimate the number of bricks of completely different shapes and sizes in ONE BIG BIN?

In theory, you would stirr everything to get one humongeous mass.
That is, you want bricks, pins, wheels, minifigs, separators all next
to each other, not in different layers with small parts at the bottom
of the bin. Next, pour it out and spread it evenly. Take a photo. Use the method
mentioned above.
Or, leave it in the bin. Take out one cup full of Lego,
count the parts, determine how many cups your bin holds and
extrapolate.

Conclusion: You're better off counting. While sorting out.

Thank you, this is extremely helpful. I might try a few different methods and average their answers. That'll probably get me as close as possible. :)

I can only add that "by eye" method is a bit tricky. I've seen bunches of bricks and allways underestimated the numbers. It is like you cannot believe there are 100 bricks of the same type. More like 50-60. But then you go count it and here you go - 100 bricks.

Right, that's an excellent point. Maybe I'll estimate a smaller number "by eye" and then I'll count to see how accurate I am or am not. :)

If the parts came from sets then you can search bricklink.com for the sets, and it will then tell you how many parts is in each set. It is then just a matter of summing them up.
If the parts are not part of a set then im afraid there is no easy way to do that, especically if the parts are quite varied.


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What material is the LEGO laptop made of?
What material is the LEGO laptop piece made of? It does not feel like their normal rubber and it certainty doesn't feel like ABS.

Probably the same as other flexible parts; i believe polyethylene.

It could be polyethylene or ABS. My guess is polyethylene because it is more flexible.

"It could be" and "my guess" aren't very strong arguments. Do you happen to have some data or source of the information to back up your answer?

@Alex Yes, I do. On my LDD app, it says made out of polyethylene. Also, polyethylene is more flexible than ABS. polyethylene would be used to make the "hinge" on the laptop, to make it close.

I wasn't aware thet LDD has such information. Your answer would greatly benefit from having such information posted in form of screenshot.

@Alex Some pieces do, some pieces don't. For example, different wall elements could be made of ABS or a variety of different plastics.


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What does this symbol on the EV3 Brick mean?
I can’t figure out how to get my R3PTAR to open and close it’s mouth to bite. I keep getting this symbol. What does it mean?

You either have to recharge your battery (if you're using a battery pack) or replace the batteries (if you're using normal batteries). If this symptom persists after charging the battery pack, try to do a master reset on the brick. Failing which, you might have to replace the battery pack.

It's a symbol for low battery power.  You have to recharge the brick.

How long?  Check out Mr. Hino's YouTube video on how long it took to juice his back up.
For a full recharge, we're waiting for the red brick light to turn off...


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Star Wars set identification 1
I recently bought a big box of LEGO that have some broken LEGO Star Wars sets and I need help identifying them. Some are fairly complete and some are just pieces. The first 2 are almost complete so it should not be too hard to identify. For the rest, I pulled out the pieces that I thought would be easiest to identify and will post them in separate questions. Thanks for any help you can provide!
This one appears to be a Wookiee ship.

The first one is the 7674-1 V-19 Torrent.

And the second one is 7752-1 Count Dooku's Solar Sailer.


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Star Wars set ID 2
This part appears to be one side of a Wookie ship of some sort
and these parts appear to be from one set but I am not sure

this appears to be an Imperial ship of some sort

and this is from a walker but not sure which one

and I have no clue on these next 3 but I am hoping that they are unique enough to identify what sets they come from.

Thanks for any help you can provide!

Welcome to Bricks, trevluk.  We prefer to keep set-ident questions to one set per question.  You got a great answer already here so I wouldn't edit the question at this stage.  But for next time try to focus it a bit more.

Scrolling... scrolling... scrolling...

The first picture is one wing of set 7959-1 Geonosian Starfighter.

Those are actually two separate sets. I believe the two on the left go to 7678-1 Droid Gunship.

And the one on the right is the Vulture Droid from set 7751-1 Ahsoka's Starfighter and Vulture Droid.

The Imperial-ship assembly is from 8017-1 Darth Vader's TIE Fighter.

Those are the legs to 8014-1 Clone Walker Battle Pack.

That is one section of 9491-1 Geonosian Cannon.

The two gray assemblies go to 7957-1 Sith Nightspeeder.

And the last two pieces appear to be in dark red, in which case, they would go to set 8102-1.

wow, awesome, I really appreciate it!


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How can you get the pipes on Steamboat Willie to work reliably?
We recently began building 21317 Steamboat Willie.  We've got it mostly built, but the pipes keep getting stuck.  The rear one works, but the front one keeps getting stuck up and won't go down.  We've thoroughly squeezed all of the pieces, but it keeps happening.  Has anyone come up with a reliable design tweak to keep the Steamboat pipes moving?

You may have the Technic mechanism inside the boat too tight. I would take off the top section, and look to make sure that all parts of the moving mechanism works freely even before attaching the smoke stacks.

We'll give that a try, but we didn't see any of the sticking before we added the brackets for the stacks onto it.

Yeah, that would be my only guess. I have built this set and experienced no sticking, and there are a bunch of online reviews and video-reviews, and none of the ones I have read/watched mention sticking. I do remember reading one review (unfortunately I don't remember which one), that mentioned the importance of making sure the Technic mechanism works freely as you build it up.

We saw a thread on the LEGO page on Facebook where other folks had similar problems, but it seems to be gone now.  I wouldn't have posted here if I didn't think it was more ubiquitous.

This is a real thing.  But the Lego response is to blame the builder.  Sigh.  Check out this fix... it substitutes a 1x2 tile for a 1x2 grill -- which is a fraction thinner and helps with the sticking problem.  https://imgur.com/a/6RdWcxD


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What set does this light grey 2x8 overhanging brick with a 10 on the side belong to?

I just received a huge box of LEGO pieces. There are some unique pieces such as this one.  On the back of this piece is the number AM02232. What are my options of figuring out its set and finding instructions? I'm brand new to the LEGO world, but kiddo is a builder at heart.

Doesnt look like LEGO brand to me, but a clone brand. Does it have the words LEGO on the top?

Welcome to Bricks.  My first thought was that it doesn't look like the way LEGO does panels these days, but maybe it was from an era of LEGO that I missed.   Looking through https://www.bricklink.com/v2/search.page?q=10#T=P&P=1 -- all of the parts that mention 10 -- I'm convinced it is from somebody other than LEGO.  Sadly that means there no way to be sure where it came from since there isn't a good database for non-LEGO parts.  If you also got any instructions just look for the non-LEGO ones.

Thanks so much!  I didn't see lego printed anywhere.

Confirmed that this is not LEGO, but Mega Bloks.
http://gamearn.me/mega-bloks-tank/mega-bloks-tank-legends-battle/
Not sure if it is from this set specifically (looks like it might have some stickers to add the camouflage or yours comes from a similar set).


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What LEGO pieces have "real-world" functionality?
I have noticed that there are a few LEGO pieces that also function in the "real-world." For example, the  10830c01 Magnifying Glass can actually magnify.

Another example is the 70001pb01 Compass, which works the same way you'd expect any "real-world" compass to function. (Although it's not always 100% accurate.)
Are there any other LEGO pieces that have "real-world" functionality?

I realize this question is specific to parts/pieces, but it seems worth noting that there are lots of sets that are useful.  I've been totally happy with my 40173 picture frame.

Isn't every item lego makes an effective caltrop when left on the floor?  More-so on hard floors rather than carpet, and damage multiplier for bare-feet.

@Criggie And now imagine an entire floor made of lego...! Bedtime in a Legohouse

@Criggie That's probably the "real world" use that I am most familiar with! xD

@chicks That's a great point. If we're talking about sets, then I suppose the LEGO Board Games would be another thing that works in the "real-world!"

This seems way too obvious for it to not to be posted yet, so I must be missing something .... but what about Lego wheels?  They are all .... wheels!  Real, proper, functional wheels!

Do you mean real-world functionality or real-world appliances?

https://gizmodo.com/desk-made-entirely-out-of-lego-285777

@yunzen Real-world functionality.

I'm stumped by how you define "real world." Certainly, almost 100% of lego pieces work in the real world? Lego wheels actually turn, hinges actually hinge, doors open, and you can actually make a wall out of plain old lego bricks. I don't see how any of those are really any different than the magnifying glass example.

@dwizum Right, I see what you're saying, but realistically, would a wall of LEGO bricks withstand the weather? Would a house made of LEGO keep you warm? Would LEGO hinges support a door for an extended period of time? Whereas if you needed to magnify small print, a LEGO magnifying glass would work just fine. Although, in all honesty, the line between "real-world" and "not real-world" uses are pretty hazy. :/

@dwizum Oh, and also, I thought I'd add that this question is primarily asking about singular pieces. So one piece by itself can't be a wall for a house or serve as a hinge for a door.

@Magnus: You should edit those clarifications into your question itself.

I guess my point is, yes a lego wall useful for humans would be impractical, but it seems no different than how useful the magnifying glass would actually be (yes, it magnifies, but it's TINY and would be incredibly awkward and/or frustrating to actually use in a similar manner to how you'd use a normal-sized magnifying glass). I don't want to come off as negative, I think this is a really great question, I'm just struggling because I see "real world functionality" as a spectrum (vs a binary yes/no) in the absence of any specific criteria.

@dwizum I just edited my question to clarify what I'm trying to say. I completely agree that it's more of a spectrum, so I added that to the end. And no worries, you're not coming off as negative, I appreciate how you are making me think deeper into this question and the underlying idea. :)

@V2Blast You're right. I just went ahead and made that edit.

The web pieces made of flexible string are perfectly serviceable real-life webs, even if they are too small for most applications.
Of course the LEGO brand magnets are working real-life magnets as well.
Some sets have included large air bellows that could be compressed manually (i.e. hit) to supply a burst of air to launch a projectile or a racecar.
The light-up bricks are naturally serviceable as tiny flashlights.
The rechargeable batteries are usable outside of the LEGO world as batteries.
The large sawblade used in some constructible action figure lines (for example Bionicle) and System lines (for example Power Miners) with the right setup could be used as a table saw to cut through paper or other materials of comparable strength.
The parachutes of the 2019 City Police sets are advertiesed as working parachutes, so I'd expect them to be ... working parachutes, at least for loads comparable to minifigures.
Almost all LEGO propeller pieces are functional propellers (having pitch and accepting an axle), with admittedly terrible performance compared to purpose-engineered examples.
The old-style 9V and newer PF electric extension wires could be used as real wires.
The electrical switches (or polarity changers) are working too.
In the same vein, the pneumatic components (pump, tube, valve, cylinder, tank, manometer) are working as well.
The Technic shock absorbers (springs) would apply too, some are even adjustable.
Naturally, all Technic gears are working gears, even if they have suboptimal shapes and materials compared to real-world examples.
The LEGO City mugs can actually hold tiny amounts of liquids.
The boat hull pieces that are advertised as being able to float, do of course float.
The treasure chest, large barrel and letterbox pieces are tiny, but functional storage items.
Some City sets include working car jacks.
LEGO has produced mirror pieces with stickers that really reflect light and of course all transparent window panels let light through. On the same topic, many door elements have working hinges and the tiny fences could be used to separate tiny gardens and to keep tiny animals from crossing over. (Caveat: almost all animals that are small enough that can't just step over it can probably climb over or fit through the holes)
Possibly the most boring example of all: the weighted brick does indeed weight quite a lot due to a metal insert and is thus usable as counterweight.

Not sure the boat hull pieces really count - I mean, LEGOs are made of plastic, and thus all float (possible exception of the weighted brick).  Being boat hull-shaped does not necessarily make any difference in that respect...

@DarrelHoffman Certainly not all bricks float and lots of them do so only as long as the air bubbles trapped on the underside are not dissolved in the water. See for example: https://bricks.stackexchange.com/a/9013/3631

All Aboard!
I'd like to add my all-time favorite LEGO piece:

x870cc02, THE BLACK WHISTLE!

The white brick is a microphone. Attach it to your train's motor and BLOW THAT WHISTLE!  Depending on how short (or LONG!) your whistling was, the train would go forwards or backwards.

Real-world use: Not only did it drive your train round the bend, but your parents too...!

You got two awesome items in one post!. The microphone is awesome too!

Minifig accessory "shovel" can be used for dispensing minute amounts of a powder. Urban legend attributes such usage to drug dealers.
The fact that amazon lists digital pocket scale (0,1 g resolution, 100g max) and an airtight container as "frequently bought together" hints it's more than just a legend and LEGO shovels are indeed used in this way.

This is the best answer. Welcome to Bricks.SE.

Look at the insane price for the shovel! Bricklink lists it as Minifigure, Utensil Shovel (Round Stem End), not to be confused with the much more expensive Minifigure, Utensil Shovel (Flat Stem End).

@Aziraphale When you're weighting a powder that's worth $100 per gram, $4.69 is reasonable investment : )

If anyone are interested, I can probably find some of those shovels to sell for $4.00 (that's a discount on several times the average price on bricklink for those).

Now the link says "page not found"

@mindstormsboi Thanks, that's why I put the screenshot.

The holes in Lego Technic work very well as holes.
By which I mean, I have built very successful motor-driven cross slides for small machine tools using Technic pieces.
When paired with nominally 4.8mm metric ground rod (which tends to have a negative tolerance) the 4.8mm holes are a nice sliding fit. Imperial 3/16" rod at about 4.76mm also works, but is a bit sloppier.
Although the hole is a little undersized for tapping M6 (5.0 required), the soft plastic easily allows a taper tap to be run through. The 1mm pitch of the thread, together with the hard metric 8mm width of the brick means that the start and finish phase of the threads is identical. If an already tapped brick is pegged as a guide to a new brick, then (a) the guide will help ensure that thread goes in straight and (b) has the same phase in both bricks. I mark a guide brick, so there's no cummulative error in creating new tapped bricks.
A piece of 6mm studding can then be used as a lead screw. It can be fitted concentrically to Technic shafts by locknutting it to a tapped brick, then pegging the brick to a 40t gear.
That's all been taken apart now. But only last week I had a measurement problem, and needed to be able to adjust the height of a stage quickly between many, repeatable, fairly precise heights. Behold, two sets of binary stacking gauge blocks, 16x8mm down to 1x8mm.

"Technic", not "Technik". (I don't know if there's anything else to fix in your answer, or I'd edit the fix in myself.)

I once published a paper in a peer reviewed scientific journal using data gathered using a remote translation stage constructed from Lego Technic.
I could only get ~ +-1mm accuracy out of it, where the proper stages were more like +- 0.1mm, but it was good enough for a proof of concept and the proper stages were on back order.
Of course many people would say that an X-Ray Physics lab is not the real world, but that's another matter!

citation needed ;-)

lol, this is the paper https://scripts.iucr.org/cgi-bin/paper?aj5138, but oddly enough I didn't mention what the translation stage was made from in the text!

non-paywalled paper, where I can almost see the stage moving along the axis in Figure 1.  https://ore.exeter.ac.uk/repository/bitstream/handle/10871/22169/X-ray%20diffraction%20from%20bone%20employing.pdf?sequence=1 Speaking of X-rays and tracks, you may also like Where (if anywhere) were X-ray machines put on trains or trolleys to image “Everybody over 14 years old”?

nice find, that's actually a different paper from the same research group but it's the same geometry being exploited, that one's from after I left the group so they'll have been using proper equipment by then (so was I after the very first PoC experiments)

Another scientific experiment that uses Lego is the squeezed light source of the gravitational-wave detector GEO600, which uses black Lego bricks for stray light baffles in its optical assembly. Here's an old video documentary
(in German) where two of the scientists test the best colour to use and you can see the finished result on p. 82 of this thesis (if you look closely).

There are also papers using Mindstorms to automate a process, making it more consistent than a student with a stopwatch.

One obvious answer is all components of the power functions family.
Lights can be used as lights, motors can be used as motors.

Those shoehorn pieces worked. Technically, all of them serve their intended purpose as bricks. The ropes function. The ball shooting contraption present in the Lego Ninjago dragons (and other sets, I bet) functioned, as well as the spring-loaded cannon pieces. The axles technically worked (but not very well in actual cars).

I've seen them serve their 'intended' purpose in the real world. My favorite piece though: the winch.

What do you mean by "Those shoehorn pieces"?

The brick puller?

@Mazura My antivirus says that webpage is dangerous.

@mindstormsboi - mine too. It's a picture where someone used a bunch to tuck point some missing (actual) bricks on the corner of a house.

Gears function quite well for creating mechanical devices such as functioning clocks:

Design by KEvronista, picture by me.
Naturally you can use an electric motor for more accurate timekeeping, as in the NXT Classic Clock (bonus model from Lego):

LEGO Mindstorms robotics kits are also a great way for kids and adults to get started with robotics, and I would bet that a good number of current robotics and mechanical engineers got their start with building LEGO robots. There's a healthy educational community and competitions such as FIRST Robotics.

Disclaimer: this is cheating a bit.

All of them!

I mean - even the most simple lego brick serves as a brick, so a creative mind can devise a real-world use for almost any brick if you have enough time, money and bricks at hand.

Robots created with the Mindstorms product line are real robots.

I suppose several of the tools in Minifigure utensil wheel theoretically could be used in certain circumstances. I.e. you could hit things with the hammer, it would probably break before you got anything useful done with it, but it can still be said to have it's functionality.

Ultimately, all functional LEGO elements can be used in the "real world" for their function.

Hinges can be used as hinges
Wheels work well as wheels
Containers (e.g. drawers) can contain things
Magnets work as magnets
Decorative elements can be used for decoration

... and so on.

They're the most prolific tire manufacturer in the world, twice over.

@Mazura By unit, perhaps. :)

LEGO rubber bands, O-rings, and belts can be used to grip things, for sealing pneumatic moving parts, and for transmitting power.
LEGO sails actually catch wind on floating vessels, and the covered wagon covers and tents keep water off whatever's underneath them.

A few lab examples that have used my parts, mainly 80s/90s Technic:

A quick spincoater made of Technic for use with microscope slides. ("We need a small spincoater.  Tomorrow.")
A syringe pusher using pneumatic Technic.  Unlike pushing by hand the syringe didn't move under the microscope when squeezed.

Both these two were for a research project; the Lego wasn't mentioned in the paper though.  BTW spin-coating doesn't work well with liquid crystals on structured surfaces, or at least not with the electric field geomtery we had.

In a teaching lab, spinning Technic plates at 20 000 rpm to look at the Doppler shift of ultrasound reflected off them (not a Lego motor, but the rest was).
Another teaching project: A Lego model of ʻOumuamua made from various colours of 2x2 round bricks and rotated using Technic.  The reflection of a light source was recorded on a photodiode to simulate observations.

I've also used Technic to make:

One-off assembly jigs to hold a workpiece on a funny angle while glue dried (engineering job)
A large setsquare incorporating a set of open sights to align a laser beam to the wall in my lab.  Lego+Pythagoras proved squarer than the building.

Essentially all Technic is potentially useful in the lab, plus other parts as needed to make it fit.

There are several lego "pieces" that function as tools for humans to use with Lego. Most notably the Brick Separator and its variations, but also Duplo Toolo Screwdriver and Wrench, RC Car Separator, and Triangle Ruler.

As a child, I successfully replaced the perished tyre on the bobbin winder of my mother's sewing machine with a Lego tyre of similar diameter.


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Run Code From PC
https://www.ev3dev.org/projects/2014/05/09/Python-Rubiks-Cube-Solver/
The other one gives a solution in around 20 steps, but takes around 500 MB of memory, so I need to run it on a computer

How do I run a code from my computer?
import socket
hostname = socket.gethostname()

if hostname == 'ev3dev':
    # We are on the EV3, import required modules directly
    import ev3dev.ev3   as ev3
    import ev3dev.fonts as fonts
    import PIL
    import os, subprocess
    ev3.Sound.beep().wait()
else:
    # We are somewhere else. Assume we are using RPyC:
    import rpyc
    conn  = rpyc.classic.connect('192.168.15.3')
    ev3   = conn.modules['ev3dev.ev3']
    fonts = conn.modules['ev3dev.fonts']
    PIL   = conn.modules['PIL']
    os    = conn.modules['os']
    getpass    = conn.modules['getpass']
    locale    = conn.modules['locale']
    #sys   = conn.modules['sys']
    namepc = getpass.getuser()
    name = (namepc.title())
    print(name)
    cv2    = conn.modules['cv2']
    subprocess   = conn.modules['subprocess']
    ev3.Sound.beep()

I've tried this code but to import cv2 takes around 2-5 minutes or shows "result expired"

Yes, it is definetley possible on Ev3, even with the older mindstorms NXT.
This link should get you started: https://www.ev3dev.org/docs/tutorials/connecting-to-ev3dev-with-ssh/
Also instead of puTTY there is MobaXTerm:
https://www.youtube.com/watch?v=ZfhqZGFJd9A


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Identify the set from this partially assembled purple and white car with a blue flower sticker on the hood?
I have loads of complete Lego sets, distributed into bags and without instructions.

Hi Nick! I took the liberty and edited your question in the hopes that it will better reflect your intent. Should I have made an error and misinterpreted your thoughts, feel free to revert or edit your question.

No problem - a novice here so all help appreciated

This is 41013-1: Emma's Sports Car:

Hi Nick! Glad to hear it was useful :) Please click the Checkmark icon to signal to others that the question has been answered.

Is that right? I have plenty more

Perfect, bring on the other questions ;)


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Custom extension cables for Light Stax?
Recently, I got the S-12012 Light Stax kit with 50 (!) light bricks. They are different from those described in this question, but they are much cheaper, colorful and with blinking/pulsating effects. However, there is one disadvantage: all bricks have to be attached to each other to lighten up. So if I wanted to light up different areas of my set I would need several of the 4x4 battery bricks (there is only one in each kit).
My question: Is it possible to to connect/solder wires between the bricks to extend the range?
The lights are LEDs, and it does not matter how the bricks are connected as long as one stud is connected to the underside of the next brick. There are contacts on all studs and undersides. I want to avoid damaging the bricks with my limited soldering skills.
I tried to use the 8886 PF Extension Wire, but that did not work.
The contacts don't match.
Pictures 3 and 4, respectively, are close up photos of the studs and undersides of the bricks. Does this help to tell how extension wires could be attached?

Is there a single LED in a 2x2 and 2x4 brick? How do you change the effects?

lightstax.eu sells single extension cables ranging from 10-80cm for little money. You could cut the leads and adjust their length, rather than modifying some LEGO plates to act as sockets. Just an idea...

@Uli Ha, I wasn't aware of the cables, thank you for the hint. This doesn't answer my question but it definitely solves the issue very nicely. The effects are triggered by pressing or holding the button on the battery brick. It is also supposed to react to sound but I haven't figured out how.

@Uli Yes, there is one LED in each brick. Most of the bricks in this set are semi transparent, a few are clear transparent.

However, with each brick being THRU as well, these off-the-shelf extensions are even YY cables. Still, is it possible to tinker one? Both pins sit on a single stud. That's tricky!

@Aziraphale: "It is also supposed to react to sound but I haven't figured out how." - it doesn't become quite clear from the instructions, but when you cycle through the modes up to the last (fourth) mode, the lights will be off unless you create a loud noise near the battery brick. That is, if you clap or yell "hah!" or something, the lights will briefly light up for the duration of the sound. At least, that's what it works like with ours.

I have also little soldering experience, but I managed to create custom extension cables:
First: open the cover with a small screw driver:

Remove the PCB by lifting the small notch to open the light block

Then you drill a small hole into the opposite side of the metal plates, insert a small 2-wire cable (~0,25mm) and solder it to the PCB.
The outer ring is Vin and the inner ring is GND.
Then put it together and have fun.

This is straight forward. Did it work on first attempt?

Do you have pictures with soldered cables?

Unfortunately, I cannot share pictures of the soldered bricks but the final result: https://imgur.com/a/Gqt8y3c. Otherwise my little one will kill me if I destroy his steam train

The battery brick can still be recharged. The most tricky part was the plate with bar to get two tiny wires in it without getting a short circuit

LIGHT STAX have their own extension cables in 10, 15, 30 and 50 cm lengths.
With 2 x 2 brick bases:

With 1 x 2 brick bases:


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Can anyone help me identify what set this bag with grey and dark red pieces belongs to?
Can anyone help me identify which Lego set this bag belongs to (it has two smaller bags inside)?

I see a "135149" to the right of the bottom "2", is that maybe a set number?

@Tweakimp - no, that is the part number of the plastic bag itself. The problem with identifying this bag is that the picture quality is quite bad (lots of reflection), and the pieces that are visibly identifiable are very common (as in: appear in thousands of sets)

Too many generic parts. Having pictures of both sides of polybag might be helpful.

I don't see any parts sufficiently uncommon to go on.

As the comments said: it's hard to tell.
But based on
Plate 2x14 in light buish gray,
Slope, Curved 10x1 in light buish gray and
Slope, Curved 3x1 No Studs in  Dark Red
i believe it is bag 2 from
75012 BARC Speeder with Sidecar

Glad I could help. Please feel free to mark this answer as correct by clicking on the little tick-icon on the left side.


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Please help with set identification from the picture of this part made car
please help identify the set that this car is part of.

This belongs to 41034-1: Summer Caravan


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Set with small white, yellow, and purple boat and lime swimmer fins?
I have a part built boat, but need help in identifying the set so we can complete the build.

This is part of 41000-1: Water Scooter Fun


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How to make a point coordinate system for EV3
I'm trying to make a internal coordinate system for an EV3 Python project I'm doing, but at a complete loss on how to do it. It needs to keep track of how it moves (with wheels) in an X, Y coordinate system. The space that the project operates in will only have the robot move in mainly X and Y directions.

What you're trying to accomplish is called Odometry, and fortunately it's a pretty common task in robotics so there's a lot of information available on how to do it. The short answer is, it's relatively easy to implement, but hard to make it work really well.
Let's make things simpler by deciding that the robot can only a) drive straight and b) turn 90 degrees. In other words, the robot reaches an x,y coordinate only by driving along the cardinal directions N, S, E, W. We can make this simplification to avoid having to use trigonometry.
Now we need some variables to keep track of a) where the robot is, and b) what direction it's facing.

Make a variable "orientation" to remember which direction the robot is facing. 1=N, 2=E, 3=S, 4=W, for example.
Make variables "X" and "Y" to remember the position. These can represent whatever units of length you want. Let's just say X and Y represent motor rotations, for simplicity.

When the robot moves straight, you should update the coordinates X or Y depending on which direction it is facing. For example, if the robot drives 3 rotations fwd:

If orientation==1 (North), increase Y by 3 (rotations).
If orientation==2 (East), increase X by 3
If orientation==3 (South), decrease Y by 3
If orientation==4 (West), decrease Y by 3.

When the robot turns 90 degrees, you should update the orientation variable accordingly. See my other post for how to rotate your robot a specific number of degrees. Assuming a clockwise rotation,

If orientation==1 (North), set orientation==2 (East).
If orientation==2 (East),  set orientation==3 (South).
If orientation==3 (South), set orientation==4 (West).
If orientation==4 (West),  set orientation==1 (North).

Assuming you always update your coordinates and orientation whenever you move, your robot should be able to (roughly) keep track of its position using this method. You can make it easier for yourself by putting the DriveStraight and Turn90 code into functions (MyBlocks, if you're using the standard Lego software). For example, the DriveStraight function/MyBlock should take the desired number of rotations, drive the robot that far, and update the global X/Y variables. Similar for Turn90. Then your entire program consists of DriveStraight and Turn90 blocks to move around, and at any time you can read the X,Y coordinate and orientation from your global variables.
One problem with this method is that for every movement your robot makes, error accumulates, until eventually its internal position is no longer accurate. The easiest way to account for this is to occasionally return to a known physical location - for example, a wall corner at 0,0 - and reset X,Y to 0,0 when it gets there. A lot of FLL robots use this technique - these robots have square edges and back themselves into corners to force themselves into a known absolute position/orientation.


text:
Is there any software except SR 3D Builder with the ability to simulate the interaction of gears that doesn't require scripting?
I'm aware that one can do that in LDCad but with scripting.
Should I invest my time in learning SR 3D Builder or is there any other option? It's just not a very intuitive software for me but I might still have to get used to it.
LDD is great, if only it had the ability to simulate the interaction of gears...

Please be aware that SR 3D Builder is no longer updated software. Keep that in mind if you want to invest time into something that might not be suitable at some point due to being obsolete. LDCad on the other side is actively developed.

Thanks, that's very valuable info.
Regarding LDCad, do you use scripting to create simulations there? Do you have some idea how hard would it be to learn scripting in LDCad to create realistic simulations for machines & mechanism LEGO models for someone with experience in C#?


text:
How To Deal With Hydrogen Peroxide After De-Yellowing?
I was able to remove the annoying yellowing effect from old white and lightgray bricks with the usage of hydrogen peroxide. With great results I have to say. Now I wonder what to do with the remaining fluid. Is there a danger to poison someone when it's used in my household? Is it ok to drain it down the sink? Any advice on how to deal with it is welcome.
Another thing, when do I have to change the fluid? Will the effect gradually decrease?

I'm voting to close this question as off-topic because the handling of H2O2 is not tied to LEGO bricks in any specific way. This question seems better suited to Chemistry.SE

The dangers of H2O2 depend greatly on the concentration, which, in turn, will quickly change with time as it decomposes to water (heat and light speed up the process). So small amounts of diluted H2O2 can be poured down the drain, by the time it reaches the main sewer, there will be nothing left that would be more problematic than the average household cleaning products that get down there daily.

Interesting point. I would say it fits in both forums. And considering the special relationship of the members of this forum to the brick in particular I would say that there is a general interest here for the topic. So, no, I would not change.

You have a point, I'll let the other members have a say in how strictly are the rules to be interpreted. Meanwhile, to see if an amount of H2O2 is still potent, one just has to watch for bubbles of O2 being generated inside the liquid from the spontaneous decomposition. No new bubbles means no more potency, and thus time for a change.

ahh, seems i have to change. Thank you Zovits for your fast help

What to do with H2O2 if you don't want to wait for it to become harmless due to spontaneous decomposition, probably depends a lot on local laws, so this might also be considered too broad.

@ Fabian, I got great results using this method too.

After doing a simple search, it seems that the general consensus is, it's okay to pour the used amount down the drain.
Most of us get it.  The stuff's been sitting in your house taking up space, and because of the unfamiliarity with this chemical, you and environmentally conscious thinkers such as yourself, would never want to further harm our shared environment.
Bottom line: No new bubbles means no more potency, the green light to pour away.


text:
Where to get 3D files for LEGO bricks?
I am constantly in search for a particular rare brick from the 1990's which is ridiculously expensive on BrickLink and also hard to get. So I am thinking about printing it on a 3D printer to be able to finish projects. I understand, a blasphemous behaviour. Please let me know where to get the needed 3D file.

LEGO doesn't (3D) print their bricks, especially not in the 90ies where 3D-printing (almost) wasn't invented yet. So you're looking for a file some random person has made for his/her own use. I've never seen a repository of such files.

well, i thought there are 3D programms that one can use for designing models and there is a library for the bricks. i would like to extract the one brick as a file. btw, the brick is in use also today but not in the color that i am looking for

What part are you looking for?

hi chicks, I am looking for "6192 - Brick, Modified 2 x 4 No Studs, Curved Top". It is a common piece but not in white. It was only used in 1995 in 3 sets. It would be great to have a STL so I can print it

The canonical location for 3D models of LEGO bricks would be LDraw, with its huge catalogue of official parts.
Another resource specifically catered to the 3D printing community is PrintABrick. Their library is not as big as LDraw's, but they offer ready-to-print STL files.

LDraw files are suitable for digital modeling, but not for 3D printing.

@Alex Good to know! What renders them unsuitable for 3D printing?

LDraw parts have just geometry. You still need to tweak dimensions, tolerances and directions after conversion. So they are not ready to be used directly for 3D printing.

I am not sure if I understand your answer Alex. My friend with the 3d printer says that he needs STL files. Would I be able to produce those with LDraw?

There is a perl script/library ldraw2stl https://github.com/kristov/ldraw2stl to convert LDraw data files to stl format that can be printed just fine.


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How to connect an NXT brick to the LEGO programmer application on an iPad?
Can you connect a NXT brick to an iPad via either USB cable or Bluetooth? For me neither seem to work even though the EV3 brick (and the LEGO programmer application) should be backwards compatible.
I can connect the NXT to the iPad: both are displayed by the other device as connected. But in the LEGO programmer, the NXT does not show up as an available brick.
I have also tried to connect with 2 USB cables that have a male to male  connection in between. There seems to be no option for that at all in the LEGO programmer.
Does anyone have another idea how I can get these two devices to communicate and download files?

The NXT only works with the EV3 desktop software (for Windows and Mac) and only via USB.
I'm not aware of any way to program NXT using an iPad (or Android, or Chromebook).


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Can the scabbard hold a castle sword
I wonder if the Dark Gray Minifigure, Weapon Sword, Shortsword part No: 3847a fits in the Minifigure, Utensil Scabbard with Shoulder Strap part No: 95348
Scabbard on bricklink

Sword on bricklink

Yes, it does, and it fits beautifully! In fact, it's one of my favorite combinations as the sword is not too long and thus doesn't drag on the ground.

I just took a picture for you and was trying to include it, but for some reason I couldn't post. I kept getting the error message "body is missing". I'm not sure what that means. Sorry about that.