text:
Identify pieces from parts list from a video
I have a screenshot of instructions from a Youtube video that include a parts list, but unfortunately no part numbers/names.
My own experience with LEGO is limited, but I was looking for a way to identify these parts to be able to buy them and make it into a gift for a LEGO and AoE2 enthusiast.
Do you have any suggestion on a good way to reliably identify these parts?

EDIT
I have changed the picture and added numbers to the parts for easier reference. I think I am already able to identify most of them through https://brickognize.com, bricklink.com and LEGO's pick-a-brick, but here are the parts I am unsure about:

2,6,13 all have a slightly lighter shade than the dark brown parts (which I have put as Reddish Brown) I would have guessed the lighter shade might be Dark Red, but would welcome some input
24, 30, 34 I am unsure which color this is supposed to be, maybe Dark Orange?
3, I am also unsure about the color - bright yellow maybe?
15 I am unsure. The closest I can think of was Brick, Round 1 x 1 Solid Stud, but it looks a bit like the sides are not smooth, so I am unsure
26 I couldn't find
31, this seems to be Body Microfigure Complete but I couldn't find it on pick-a-brick
35, I think it is Fence 1 x 4 x 1 Lattice but would welcome confirmation
11, 13, 20, 40 I could identify, but didn't find it on pick-a-brick to order - does that mean I misidentified or that it is not produced anymore?

Which of these parts are you having trouble identifying? Can you mark it somehow, like circling it in the image? Most of them are very basic ones and so identifying all of them would probably be a waste of time.

@zovits thanks for the comment. Should have highlighted from the start. Let me check and edit accordingly

@zovits I have gotten around to editing as per your request. There are now small numbers next to the parts in the picture. I think with circles the picture might have become less readable

I found some answers on Bricklink, Rebrickable and other sources:

#
Amount
Name
Part #
Color

1.
13
Tile 1 x 1 with Groove
3070, 30039, 35403, 39727, 53836
Reddish Brown

2.
4
Tile 1 x 1 with Groove
3070, 30039, 35403, 39727, 53836
Dark Red

3.
1
Tile, Round 1 x 1
98138, 35380, 35381, 39797
Pearl Gold

4.
1
Plate 1 x 1
3024, 28554, 30008, 63326
Reddish Brown

5.
106
Slope 30 1 x 1 x 2/3
54200, 18862, 33847, 35338, 50746, 63290
Reddish Brown

6.
56
Slope 30 1 x 1 x 2/3
54200, 18862, 33847, 35338, 50746, 63290
Dark Red

7.
9
Tile, Modified 1 x 2 Grille with Bottom Groove / Lip
15561, 30244, 35248, 51815, 71957, 72582, 78812
Reddish Brown

8.
6
Plate 1 x 2
3023, 6225, 28653
Reddish Brown

9.
2
Plate 1 x 2
3023, 6225, 28653
Light Bluish Gray

10.
4
Plate, Modified 1 x 2 with 1 Stud with Groove and Bottom Stud Holder (Jumper)
15573, 78823
Reddish Brown

11.
15
Plate, Modified 1 x 1 with Tooth Horizontal
49668, 35162, 49673
Reddish Brown

12.
4
Plate, Modified 1 x 2 with 1 Stud with Groove and Bottom Stud Holder (Jumper)
15573, 78823
Light Bluish Gray

13.
1
Plate, Modified 1 x 1 with Tooth Horizontal
49668, 35162, 49673
Dark Red

14.
20
Brick 1 x 1
3005, 30071, 35382
Reddish Brown

15.
1
Brick, Round 1 x 1 Open Stud
3062b, 18860, 30068, 35390
Reddish Brown

16.
24
Brick 1 x 1
3005, 30071, 35382
Light Bluish Gray

17.
18
Brick, Modified 1 x 1 with Stud on Side
87087
Dark Bluish Gray

18.
1
Plate, Modified 2 x 2 with Groove and 1 Stud in Center (Jumper)
87580
Reddish Brown

19.
2
Slope 45 2 x 1
3040
Light Bluish Gray

20.
2
Minifigure, Weapon Knife
44658a
Dark Bluish Gray

21.
6
Brick 1 x 2
3004
Light Bluish Gray

22.
681
Brick, Modified 1 x 2 with Masonry Profile
98283
Dark Bluish Gray

23.
1
Plate 1 x 4
3710
Light Bluish Gray

24.
2
Plate 2 x 3
3021
Dark Orange

25.
2
Brick, Modified 1 x 2 with Open O Clip Thick (Vertical Grip)
42925
Dark Bluish Gray

26.
2
Bar 3L (Bar Arrow)
87994, 17715, 19385, 37078
Light Bluish Gray

27.
12
Brick 1 x 3
3622
Light Bluish Gray

28.
20
Slope 45 2 x 2
3039
Light Bluish Gray

29.
4
Slope 45 2 x 2 Double Convex Corner
3045
Light Bluish Gray

30.
2
Slope, Inverted 45 2 x 2 Double Convex
3676
Dark Orange

31.
2
Body Microfigure Complete
85863
White

32.
7
Plate 2 x 4
3020
Reddish Brown

33.
6
Plate 2 x 4
3020
Bright Blue

34.
4
Plate 2 x 4
3020
Dark Orange

35.
6
Fence 1 x 4 x 1 Lattice
3633
Reddish Brown

36.
6
Window 1 x 2 x 2 Flat Front
60592
Reddish Brown

37.
1
Brick 1 x 2 x 2
3245c
Light Bluish Gray

38.
3
Plate 1 x 6
3666
Light Bluish Gray

39.
2
Plate 2 x 6
3795
Reddish Brown

40.
2
Minifigure, Shield Ovoid
2586
Bright Blue

41.
2
Plate 1 x 8
3460
Bright Blue

42.
12
Plate 1 x 8
3460
Reddish brown

43.
6
Plate 1 x 8
3460
Light Bluish Gray

44.
6
Slope, Inverted 75 2 x 1 x 3
2449
Reddish Brown

45.
2
Panel 1 x 2 x 3 - Hollow Studs
2362b, 30009b
Reddish Brown

46.
4
Plate 2 x 8
3034
Light Bluish Gray

47.
2
Brick 1 x 8
3008
Light Bluish Gray

48.
2
Plate 1 x 10
4477
Light Bluish Gray

49.
2
Arch 1 x 6 x 2 - Medium Thick Top without Reinforced Underside
15254
Dark Bluish Gray

Notes:

Picture shows incorrect amount. You need 68 pieces of Brick, Modified 1 x 2 with Masonry Profile to actually build that model. Checking individual steps the number of bricks adds up to 68.

Thanks for taking the initiative! If by your last sentence you mean "other users can add more pieces that I couldn't recognize" then you can explicitly invite others to do so by setting the answer to a community wiki, that can be easily edited by anyone.

thank you for this first list. Helped me a lot to get started in the right direction. I have edited my question to highlight the once I have most trouble with and also assigned numbers to the bricks.

I turn on my community wiki for some more fan-genearared edits on my answer.

I have added my current status of research. Is the color you put as LBG the "Light Blue Grey" from bricklink and equivalent to what Lego calls "Medium Stone Grey" on pick-a-brick

@Auther No I meant "Light Bluish Gray" on my BL.

@FlyingTeller : "Light Bluish Grey" and "Medium Stone Grey" are indeed different names for one and the same color.

Great collaboration everyone :)

Thanks to all of you for contributing


text:
Error while downloading ev3dev onto my ev3 brick
I am trying to flash ev3dev onto my 32GB microSDHC card, using BalenaEtcher, but after flashing I get this error:

Something went wrong. If it is a compressed
image, please check that the archive is not
corrupted.
The writer process ended unexpectedly

Is this to do with the SD card or the image itself. On the ev3dev website, it says

The release can be a .img.zip or .img.xz; whichever you have will work with Etcher.

When I download it I get a zip file like this:
ev3dev-stretch-ev3-generic-2020-04-10.zip
 - ev3dev-stretch-ev3-generic-2020-04-10
  - ev3dev-stretch-ev3-generic-2020-04-10.img
  - .meta

Am I meant to flash the whole zip file,just the .img file or something else? I have tried both and they both cause this error. If I just plug the SD card in anyway, it just stays on the loading screen forever.
I am on Windows 11 (24h2)
If I press ctrl+shift+i and look at the console, the extended error message is:
index.js:2 Error: The writer process ended unexpectedly
    at i (index.js:353:5238)
    at t.createUserError (index.js:353:6464)
    at m (index.js:140:45502)
    at index.js:140:46208
    at L.<anonymous> (index.js:140:42787)
    at L.emit (node:events:518:28)
    at e.exports.H (index.js:2:2313625)
    at e.exports.emit (node:events:518:28)
    at index.js:2:2289445
    at process.processTicksAndRejections (node:internal/process/task_queues:95:5)
2
index.js:2 Starting...
media/icon.png:1
 Failed to load resource: net::ERR_FILE_NOT_FOUND
index.js:2 Verifying 1 device, 99% at 5.70 MB/s (total 5.70 MB/s) eta in 0s with 0 failed devices
3
index.js:2 Amplitude Logger [Warn]: {code: 0, error: "Status 'unknown' provided for 2 events"}
index.js:2 CHILD: flash done
Object
index.js:2 Flash results
Object
index.js:2 Starting...
index.js:2 Amplitude Logger [Warn]: {code: 0, error: "Status 'unknown' provided for 2 events"}
index.js:2 Amplitude Logger [Warn]: {code: 0, error: "Status 'unknown' provided for 2 events"}
2
index.js:2 Amplitude Logger [Error]: Event rejected due to exceeded retry count

I thought we had a noticed about this on the ev3dev site, but apparently not. Etcher version high than v17 are broken. You can get the older release here: https://github.com/balena-io/etcher/releases/tag/v1.17.0.

I am now using the older version of etcher, and now it gets to the "validating" phase. But once it gets to 2%, it stops, and raises and error; "Something went wrong while writing". Also, just before, the drive disappears from my file explorer, I guess disconnecting from my device. Is this a problem with my SD or another bit of software?

Ran it again, here is my stack trace from the console: rror: Error invoking remote method 'enable-screensaver': No handler registered for 'enable-screensaver'
at EventEmitter.i.invoke (node:electron/js2c/renderer_init:57:526)
(anonymous) @ gui.js:37
3gui.js:37 Amplitude Logger [Error]: Event rejected due to exceeded retry count

It does sound like there could be something wrong with the microSD card itself or something unusual with the computer you are using.

source: Stack Exchange

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

sort: votes


text:
Minifigure overview and Combinator
Does anyone know a website or program which provides an easy overview over LEGO minifigures and allow me to recombine parts from different minifigures and show me kind of preview picture?

As noted by J.C. Tchang, some options include leocad's minifig wizard...

... and bricksmith's minifig generator:

I will go with LeoCAD’s Minifig Wizard, although i wish it had some Filtering or Search function

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


text:
Help ID this set!
My school received a bunch of built Lego donations. However this was in with it and we don’t have instructions or know the set!
6 bags has bag three with blue pink and purple mostly with pieces that remind me of a steering wheel for a ship! Has pieces with eye lashes
Every time I upload a photo it says too large

"Every time I upload a photo it says too large" Have you tried to resize your images? Today's cameras and smartphones take pictures of previously never seen resolution and thus file size - a 50% reduction in the resolution would probably result in a fitting, yet still recognizable image.

Based on the fact that most (if not all) lego "classic" sets group colours by bags, and my guess that "pieces that remind me of a steering wheel for a ship" might mean round plates with gear teeth, I can make an educated guess for set 11019.
Note that the instructions booklet for the set show that a blue-pink-purple assembly with gear plates and lashy eyes can be made from bag 3:


text:
I have a pair of bricks that I would like identified. They are like a Slope 33 3 x 3 Double Convex Corner but with an uptick
I have a pair of unusual bricks that I would like identified, I have lost the instructions so cannot identify them.
I have tried searching on Bricklink and Rebrickable (even Google Image search) but cannot find them.
They are like a Dark Red 3675 (Slope 33 3 x 3 Double Convex Corner) but with an uptick on the opposite corner.

EDIT:
It's certainly not warped, it is curved by design, but perhaps it is not genuine lego, although I cannot remember buying any other sets.

Are there any letter or number markings anywhere on the part? Inside the stud hole, underneath?

I suspect this is not a LEGO element. I would expect to see "LEGO" inside studs.

Just has the number 6 underneath, LEGO does not appear when the holes are inverted like that.

What = an uptick? Can't see it. Maybe Minitalia, Italian Lego 1970's as hollow stud.

@james.cookie since when does LEGO not have their logo inside recessed studs? Maybe you aren't looking at LEGO elements in your collection? I did a quick check on few random parts than have recessed stud (a window frame, Technic brick and a brick with studs sideways) and all of them have a LEGO logo inside. Same window frame has a logo inside all recessed studs, even the one that have PIP (Plastic Injection Point) like you see in your picture and still have a logo there, albeit less readable/incomplete. And your piece is large enough to have more than "6" as Part ID on the underside.

Alex - perhaps you are right, I have checked other parts with recessed studs and they do all have the logo inside (just never noticed before!)

I have found it - it's Kre-O rubbish:
https://www.amazon.co.uk/Hasbro-Transformers-Grimlock-Street-Attack/dp/B00KONR5Z6


text:
What set is the best value for what you pay (lowest average cost per brick)?
Which Lego set is the best value for its cost? What I mean, is if you were to find the average cost per brick, which set would be the lowest? I feel like it would be something with lots of tiny pieces, like a mosaic, but not sure what exactly it is.

Depends on what you mean by "vaue", really. Number of parts? Rare minifigs? Play time?

@IvanSanchez : the op specifies "lowest average cost per brick" as their criterium for best value.

For what it's worth, I think this question is unfairly getting downvoted and close voted. I find the question to be clear and with a straightforward and useful answer. I suspect the title is part of the culprit, so I've augmented it with what was specified in the body of the question.

@SanderDeDycker In that case, this is a duplicate of https://bricks.stackexchange.com/questions/9545/what-sets-have-the-best-price-per-part-ratio/

Does this answer your question? What sets have the best price per part ratio?

@IvanSanchez : so it is. I missed it.

For miscellaneous building, I can get a 1300 piece parts box for $50 at Costco when they're on sale. For specific MOCs, since I don't build much, I've found ordering exactly the needed pieces the most cost effective.

Brickset allows you to sort sets by "price per piece" if that's the metric you're interested in. Go to the sets browser, select a year and/or theme, and choose to sort by "Price per piece".
For 2023 eg., that yields the limited availability set 66747 Animal Play Pack with 486 pieces at a recommended retail price of $14.97, coming to only 3.1c per piece.
As you suspected, sets with lots of small parts can have an even lower price per piece. For example, set 41935 Lots of DOTS contains 1040 pieces (all 1x1 tiles of different shapes and colors) at a recommended retail price of $19.99, coming to only 1.9c per piece.


text:
Identify part for a build aggg stuck
The part is shown in the picture.  Fingers crossed.

It used to be in 90ies/2000 sets the basique one for a licence plate in each car in sets.

That's part 2436 "Bracket 1x2 - 1x4".

Thank you!  cheers!

@Copmedic Please see the following article: What should I do when someone answers my question?.


text:
What is the rationale behind 32333 "Technic Pin Connector Block 1 x 5 x 3"?
I never had this piece so I bought a couple to play with.
I've found that the 3 dimensions I've labeled A are all the same, 3 units long. But lengths B and C don't connect with a standard beam. Knowing how much thought Lego puts into piece design, there must be some reason for the length, or a reason for the angle of the sides? It couldn't be arbitrary.

More to the point, what is this piece for?

This part was designed for use with the Technic Engine Cylinder 2850a (or  2850b). Like this standard V8 engine:

source
The strange geometry is due to the piston shafts needing to align with the lower central pin hole.
I've made a diagram to (attempt to) illustrate this. The three red triangles are the same shape.

Adding to this, the top center hole and holes directly adjacent to the bottom center hole are spaced in such a way that they provide a solid 3-point mounting arrangement for each end of the assembly as a whole when used as part of a larger Technic build. For example, set 42125 (Ferrari 488 GTE AF CORSE #51) uses this mounting approach, with the connections on the front-end of the engine block being clearly visible in the back of the cockpit.


text:
How to connect NXT brick to EV3 programming software for mac (2024)
I have an NXT brick (most likely from 2006 based on a newspaper clipping I found in the box) that I want to program the NXT brick with the EV3 programming software (the newer version of the EV3 app for Windows 10+ and later mac versions). I read online that you could do this, but for some reason the EV3 software isn't recognizing the NXT brick that I have plugged in. Using macOS 12.7 and NXT screen is dead like a lot of NXTs.


text:
Heads Up! Could not open project!
I am a competititor of WRO (World Robot Olympiad) and I am using an EV3. I was programming yesterday and today when I opened it, it was unable to open and said: Heads Up! Could not open project!. I also found that there was another article, but I didn't understand it, and also this one was closed, so I just wanted help for my competition and I really want it back, thanks, Alex


text:
Create a gimbal like structure with Technic gears
I would like to attach a sensor to a plate, and tilt that plate slightly in the XY direction respectively, without moving the plate itself.
Similar to this (force feedback joystick concept) like this one:

But not for force feedback, just for using two servos to adjust the plate's left/right (X) and front/back (Y) direction.

Do you want to translate the plate, or do you want to tilt the plate?

I believe the answer to that would be Tilt.

I immediately had to think of the Lego Ideas 21305 Maze set. It has this kind of setup built into it, with two knobs to control the bi-axial tilt of the upper plate.

Are you working under any size constraints (height, width) ? And how many degrees of tilt would you need in each direction ?

@SanderDeDycker yes, size constraints are around 1 sq inch for a quadric plate that should be able to tilt around 10 degrees in each direction (for a total of around 20 degrees in x tilt direction and the same for y, if that makes sense)

The link looks like it would be roughly the solution, but looking for a minimal solution for a plate size of roughly 1x1 inches

@user3607022 can you please tell your size constraints in LEGO dimensions - studs.

Hmmm, perhaps 5

@user3607022 You might wanna read https://en.wikipedia.org/wiki/Euler_angles#Tait%E2%80%93Bryan_angles and use "roll" and "pitch" instead of "front/back" and "left/right".

Ok yeah so it'd be Pitch and Yaw then.

Check out the instructions (around steps 10-11) of 8855 Prop Plane. This model has a control stick that can tilt around two perpendicular axles:


text:
How to get the building instructions for a third party typewriter set?
Does anyone have the manual for this LEGO typewriter clone by chance? I dropped my model and it broke into parts - now I don't know how to put it back together.

I found out that this isn't a knockoff set, this is just the original idea for the typewriter set submitted on Lego Ideas. If you go to the set's Ideas page ( https://ideas.lego.com/projects/075a31a1-7b54-4206-857c-7a9009405cc4 ), there's an Instructions tab but it just redirects you to the instructions for the official released set on Lego.com... Do you remember how you got the instructions? Did the author share a pdf of the original instructions at some point before the official set was released?

@ToomanyBees aw man, I think I got the kit from Temu or eBay of something. Tossed the manual and box after I finished putting it together.

Definitely a knockoff set. Produced by Qizhile, reverse engineered from the pictures of the lego ideas set even before the official set went into production. As such there is very little chance there are digital instructions available.

@Raksha If you want to have instractions, the most you could do is ask the manufacturer (little chance they will even respond) or find other people who bought this exact set and managed to hold on to the building instructions, and hope someone of those will take the time to scan and upload theirs. However, if your goal is just to put the typewriter together again, you'd probably be done sooner by taking the still connected parts and treat them as a 3D puzzle.

@MichaelVerschaeve thank you, I'll try reaching out to them.

The parts in the second photo seem comfortably large and specific, so coupled with the first photo, I'd estimate a restoration to take no more than an hour or maybe two.

@zovits you'd think so but the actual button mechanism is broken too so now they either don't press at all or get jammed


text:
How to create two surfaces sloped into two directions?
I'm trying to build two surfaces like shown in the figure. Both surfaces are sloped into two directions. The side that remains flat needs to be around 51 studs long (see picture). It is therefore hard to do it with regular sloped plates like a 12x3 (47397). I tried several things with jumping sloped bricks, but of all the bricks the slopes are too intense to achieve a good result over this length.
Does anyone have any good suggestions for building techniques that would work for this. I've been stuck on this for a while.

You say the longer side is about 52 studs, but how wide should the surface be?

I just added a new picture, indicating the surfaces and the dimensions.

Ah, it seems I have completely misinterpreted the 3D angles.

For such gentle slopes I would try using the rigid pneumatic pipe parts: you can mount them by both ends of the building at specific heights to form lengthwise chords and use plates with clips to affix tiles or plates to them across that would become the surface.
See this tablescrap for how it could work and how it would look like:

Thanks a lot for your suggestion. Indeed a nice technique to create a slope over a longer distance! I will try to make a sketch with the remaining dimensions of the surface later this week, if I have time.


text:
How to build this flower?
I found this picture of a flower in a book and would like to build it. I'm wondering what's inside the white bloom?

It seems to me this would be made something like pictured below. Obviously flower stems need to be rotated for better alignment and may need to attach an extra apollo stud brick to make some space.

Key parts:

Brick, Modified 1 x 1 with Studs on 4 Sides
Plant Flower Stem with Bar and 6 Stems. Other options.
Plate, Round 1 x 1 with Flower Edge (4 Knobs / Petals) or Plate, Round 1 x 1 with Flower Edge (5 Petals)
Plate 1 x 1

Awesome, thank you very much!

There is a very similar design to this tree used in the 10247 Ferris Wheel set. (Page 96)

It uses another part (6081986) Bar 6L with Stop Ring which cannot be seen which strengthens the connections between the round bricks to stop it from snapping.


text:
Falcon Shield Attachment
If I want to attach the Falcon shield to a wall, what kind of attachment do I need? I suspect I need a horizontal clip but I'm not sure.

a horizontal clip won't work because on the back the shield has both a vertical and a horizontal bar and the horizontal one will be in the way. The way Lego uses to attach this kind of shields to a wall is to use a Brick, Modified 1 x 1 with Stud on Side and put the horizontal bar of the shield into the hole of the previously mentioned brick.


text:
Has anyone else had problems with the tail rotor drive shaft on the Lego Airbus Model 42145?
I am partway through this build and at step 565. I have found the drive mechanism to be very tight and have tried to loosen the drive elements as much as possible.
I have found what I think is a weakness in the design at step 515. Basically, a key part of the drive is this linkage where the white connector sleeve is linked to the other elements with smooth-ended connection pieces.
When at stage 565 I found this simply slips as there is no positive drive link between the sleeve and two blue connectors.
My solution has been to replace the white sleeve and two blue connection pieces with a solid splined connector that I happened to have spare. I hope it now works when connected.
I have attached two photos to show the original detail and my "fix".
  Am I missing something here ?

The "white connector sleeve linked to the other elements with smooth ended connection pieces" is certainly the intended way to build the model. The lack of rigid connection there acts as a torque-limiting clutch, preventing damage or injury if anything gets caught in the tail rotor while it's spinning.

Thank you Zovits - I had not even thought about that. However, I have now attached both ends together and it works really well. I shall be careful not to put my fingers in the tail rotor :)

@MikeP You're welcome :) If an answer has helped you, please consider accepting it as outlined in the [tour] to let others know the issue has been solved.

What is the serial number of the piece you put in there?
Thanks.
@zovits

@Susanscott I've built it as intended according to the instructions, using the original White 62462 Technic, Pin Connector Round 2L with Slot (Pin Joiner Round).


text:
Salt Lake City Temple : Spires
I'm trying to plan the tops of the spires for a lego replica of the salt lake city LDS temple.  Here's a picture:

I figure I can use a technic ball joint for the round parts, or a ski pole  for the top part but I can't use them together as there's no open axle on top of the ball joint.  Is there any kind of sphere that a bar can be put through?

"Bar" items can fit into Technic "axle" hole. Based on that I have couple of options. Both are similar to Technic ball joint you've found, but have holes on both ends.
Technic Ball Joint with Through Axle Hole.

Technic Ball with Grooves

I'll suggest using 15395 2x2 dome bottom and 553 2x2 dome top. The dome top has a stud with hole on its end, which makes it very easy to place a ski pole, or a 1x2 plate to support a minifig:

There's downsides to this approach, though:

The shape of the domes is not entirely round
The 2x2 bottom dome in light grey colour is quite rare, and therefore relatively expensive in the aftermarket.

Another option is to use 44358 3x3 ball turret socket and 44359 3x3 ball turret. These have been used as cannons in several Star Wars sets and should be easy to find.
The 3x3 ball turret provides an axle on top - in order to provide a stud for supporting a minifig, you may modify a 6587 3L axle with stud, cutting it down to 1L so it fits flush within the top part of the ball turret. I know cutting down parts is frowned upon by purists; and fitting the axle flush may make it hard to get it out.


text:
What set is this from? (spiky transparent blue with axle hole in the center)
Does anyone know what this piece is? I have asked people around if they know what piece it is. They didn't know it. It has an axle hole in the center.
All help appreciated

Looks like part 98578 Hero Factory Weapon: Spiked Ball, Half in transparent dark blue (found by a bricklink search for pieces named "half" in trans-blue).
It appears in two sets: 70202-1 "Chi Gorzan" from Legends of Chima, and 45560-1 "EV3 expansion set".

Given that the posters previous question was about programming, I'd think that the EV3 expansion set is more likely. Also regarding ownership, I've bought half a dozen of this set. At the time, there were some online stores around here that offered them significantly cheaper than RRP and the boxes were ideal part donor sets for anyone interested in technic/mindstorms....

That's a good point. I'll rephrase.


text:
5x3 Half Round Problem
How can I hide on top of this with tile pieces?

To make it like this:

Edit:
Thank @jncraton for the solution
Before answering I made it like this:

But now it looks way better and it will be more stable:

If the two small 1x1 quarter round tiles need to have clutch (meaning when you turn the build upside down, they won’t fall out), I am afraid the answer is “You cannot”.

Okay, thank you, but i was sure someone achieved something like this before.

How much of the volume do you have available for supporting the two quarter round tiles ? Just the volume directly underneath the tiles ? Or more ? How much more ?

Would two Cylinder Half 1 x 2 x 1 fit eg. ? (edit: I see @jncraton had the same idea)

@UranMaster Welcome to Bricks.SE and thanks for the clear pictures of what you are trying to achieve.

If you are able to use up some additional space inside the build, you should be able to use 68013 Brick Round, Half 1 x 2  (one under each tile) to support the corners:


text:
Extra wing pieces (21+22) in Ferrari Daytona 42143. Did I miss a step or did Lego get it wrong?
The Ferrari Daytona SP3 (42143) is supposed to have 10x 6319983 (small wing #22) and 11x 6316923 (small wing #21), both in black.
It says so on the part-list and they are in the box.
However I have 1 of each left-over after the build and I can't see where I missed an assembly step. (I may have missed something, but I can't figure out where, even after going over the 800+ pages of the instruction books again.)
As far as I can tell these pieces are located in the following spots on the model:

Front lower spoiler: 2 of each
Head light surrounds: 1 of each
Front side spoilers: 1 of each
Rear diffusor and valence: 4 of each
engine top-cover: 1 of each
And 1x #21 on the passenger side of the dashboard.

That all adds up as 9x #22 and 10x #21.
Either I missed something (can someone please tell me where in the model they were supposed to go) or Lego got their part-count wrong.
Which one is it?

The instructions had several errors. Here's an overview:
https://racingbrick.com/2022/06/lego-technic-42143-ferrari-daytona-sp3-instructions-errors-and-fixes/
One of them is the two panels you mentioned, they ideally should be added in step 1127, but you should be able to add them afterwards as well. There should be two red axles sticking at the back near the bottom where they attach.
Jordan Paxton (Engagement manager for the Lego group) was at the Parades De Coura lego fan weekend last weekend and explained during a Q&A session that the missing instructions happened because of something earlier in the build steps that needed to be updated and the update cascaded until this step and caused missing pages.
I've been told that rather interestingly the parts are also missing in the picture of the model on the box-art.

Aha... And I spotted those other manual errors myself as well. Already fixed. The mounting position is easily accessible on the complete model. And found another (minor) error: step 978, 979 have the angles wrong on fairing pieces #61 and #63 which looks really weird. Funny enough the corresponding steps on the other side of the vehicle don't have this mistake.

From the bottom of my heart: THANK YOU! I had the exact same problem.


text:
What's the easiest way to build a delta robot using LEGO Mindstorms 51515?
I'm fairly new to Lego Mindstorms and I'd like to assemble a pick and place mechanism.
I was looking for existing delta robot designs and found a lot of good looking designs:

https://www.youtube.com/watch?v=TbXBTZhhlYs&ab_channel=HiroLaboOECU
https://www.youtube.com/watch?v=sGPw-bnQF-k
https://www.youtube.com/watch?v=OmMKpRE4X5w
https://www.youtube.com/watch?v=Bs1SoyfvZ4Y
https://www.youtube.com/watch?v=rjV4PJEjDKg (not a delta, but still a parallel robot)

The majority are use Lego NXT. I'd like to use Mindstorms 51515 and hope it's a matter of swapping servos, maybe some minor part adjustments (due to difference in servo dimensions) and porting the code over.
The HiroLabo delta robot looks the simplest to me (but I might be wrong, so please correct me). What are the parts used for the arms and circular base (labelled as parallel links and universal joints) ?

What are the parts used for the [Hirolabo delta robot's] arms and circular base (labelled as parallel links and universal joints) ?

Let's see another still from that video:

There I see:

2736 Technic axle 1L with tow ball
32293 Technic, 1x9 link, AKA "Technic steering link 9L"
4185 Technic wedge belt wheel
41678 Technic, axle and pin connector perpendicular double split
2L pins
4L axle
Red ball

I'd like to use Mindstorms 51515 [...]

Well, I'm looking at the parts list for 51515 and am seeing no universal joints and only four towball axles. Seems like you'll need to replace each universal joint with two perpendicular joints.
Working with a limited selection of parts is always challenging, but I think 51515 has everything you need. Try something like this for the actuator and the base of the parallelogram:

The key is using 6536 Axle and Pin Connector Perpendicular to provide the extra degree of freedom. It's gonna be worse than a universal joint or a ball-and-socket joint, but it's what you've got. Remember to use the low-friction gray pins for the joints (instead of the high-friction black ones).
I've drawn only one arm, but the other one is symmetrical; and I haven't drawn the pins - add them as needed.
The top part would also use two connector blocks, and perpendicular-axle-pin-connectors for the arms:

Since 51515 doesn't have any parts with an hexagonal pattern, or any other easy way of achieving a 120° angle, you'll have to rely on interconnecting the upper assemblies (with 3L pins):

That still looks flimsy, so consider reinforcing the assembly with more interconnections.
You'll need to fiddle and test, but I think this design should provide you with a solid base to start tinkering with.
Also note that the joints in this design are lacking a degree of freedom, and that this might apply excessive torsion to the beams used in the six arms. Experiment with adding an additional 6536 perpendicular-axle-pin-connector to each joint to provide that extra degree of freedom.

Of course, you can always go shopping for more parts. In your case, you would only need twelve of 32474 ball joint and 93571 ball joint socket. You should be able to acquire those from the usual marketplaces (pick-a-brick, bricklink) for about 0.5$/0.5€ each pair, or about 6€/6$ the full set.
Welcome to the rabbit hole of "I just need to buy one more of that one piece".

"low-friction black pins for the joints (instead of the high-friction blue ones)" - are we talking about the same pins I'm thinking about, where the black have the extra friction ridges and the blues don't? https://www.bricklink.com/v2/catalog/catalogitem.page?P=2780

My bad, I had in mind the 3L blue pins with friction and the 2L blue pin+axle with friction. The 2L pins without friction are the grey/bley ones.

OMG this answer is amazing! Thank you so much for the detailed information: much appreciated !


text:
NXT - Mirror motor rotation
I'm trying to make a program in NXT 2.0 that mirrors the (manual) movements of one motor to another.
I managed to start motor B running in the right direction but I am having trouble controlling the number of degrees. I tried using the degree output of the sensor as input for the motor but it doesn't work: the B motor moves a bit but not the same amount of motor A.

So I tried with a loop instead: rotate motor B until its position is equal to motor A.

The second solution works slightly better but is still not precise.
Any suggestions?

@user253751 doesn't look like it's possible. I can only set the amount of degrees,  rotations or time

@user253751 it (should) rotates of the given degrees from the current position

@user253751 I've tried that already. I'm passing the value to the motor but it doesn't move the right amount.

A good way to do this is to use a control algorithm with feedback to control the position of the second motor. You can research "PID" to learn how to make your own.
Or if you want an out-of-the-box experience, there is a PID block from HiTechnic available that does this. It can be downloaded from here (search for "PID"). There is also a YouTube video showing how the block works.

That's great! I didn't know you could program your own blocks. Is there a guide on how to create them?

This sounds like a great question that others might be interested in. So you should ask it as a new question rather than in the comments. :-)


text:
Minifig head with orange glasses - Which set is it from?
I am trying to make a LEGO minifig self-portrait, and I found a head that looks similar enough.
But I can't for the life of me figure out which set this is from.  Do you know?

https://www.bricklink.com/v2/catalog/catalogitem.page?P=3626cpb0469#T=C&C=3
I am aware I can buy the head in isolation, I am just curious if anyone knows the set it comes from.

This is likely from the Skier in CMF Series 2:

TLG has used a number of different head molds at different times. The head that you linked to is the hollow stud mold, whereas the one listed in the inventory for the set uses the blocked open stud mold. My guess is that a small number of these sets used the blocked open stud mold, and that's how there are a few of these floating around.
If you're curious, these are the main mold variations:

Awesome find, thank you so much!


text:
How to get a random value in the Robot Inventor software (Python)
I am making a Python program with the LEGO Robot Inventor software which will, among other things, turn the robot a random amount periodically, which of course requires a random number. However, I could not find any way to do so. Is there any Python function which I could use to get a random number?

Python has this built in. Or is there some reason you can't use it?

Thanks! I had simply not known about that function.

Not every function from full python is necessarily available in every partial (or micro) python implementation, so I wanted to check first before going down a more elaborate route.

Links tend to break. Could you give a code example in your answer in case the link is no longer available?

I'm guessing python.org is pretty safe.

In case anyone is looking for a concrete example using (Micro)Python's random, I created a small program that randomly displays images in the hub. You can find it here https://nbviewer.jupyter.org/github/arturomoncadatorres/lego-mindstorms/blob/main/examples/programs/random_images.ipynb?flush_cache=True

Under operators, there is a block "Pick Random" where you can specify to pick an integral number between x to y... x and y you can type... So for a random direction, set it between 0 and 359 degrees ...

I am actually using python, so this solution is not really applicable, but that's my fault for not saying so.


text:
Battery Box 8881 not providing enough power
I bought a used 8881 PF AA battery box. It doesn't appear to work with anything. When I test it with a multimeter, I only get a voltage reading of ~0.5V.
I tested each of the batteries, and they each come out ~1.6V (as I'd expect from an AA battery).
It may be that I'm not using the multimeter as intended and that both the lights and the motor I'm using to test this are broken, but it seems more likely that there's a problem with the battery box.
Any thoughts on what the problem might be?

In case anyone else has this issue - cleaning corrosion off of the connections solved the problem!
To clean the contacts, I used white vinegar applied with a cotton-swab/cue-tip. I dried it off with a dry one, left it for about half an hour, and after that it worked perfectly. I watched this video to be sure there wasn't anything I needed to do that I was missing.

Yes, leaked batteries did this I presume. I think I've cleaned about half a dozen over the years. In the past, this battery box was very common, so easily and cheaply replaced if the contacts were too corroded, however with the power functions phased out recently, they are getting more expensive

@MichaelVerschaeve Definitely looks like corrosion from old batteries. Power functions seems like a much simpler system which I why I went with it, plus powered up stuff seems a little overpriced to me, maybe I'm just not familiar with the kind of prices to expect :)

@Criggie Added now - thanks for the pointer


text:
What internal electronics does the Control+ Technic Hub (88012) use?
I'm interested in comparing to the other Powered Up hubs, which are already documented here:

Mindstorms v4 / spike prime What internal electronics do SPIKE Prime and Mindstorms v4 use?
train 6AAA hub What electronics are inside the LEGO Powered Up hub?
boost / move hub What internal electronics does LEGO Boost use?

Thanks!

Welcome to Bricks! I contributed answers for the three linked questions, but I don't have 88012. I'm sure I'll get it eventually, and I'm happy to open it up and document it here when I do, but it would likely be months from now. Perhaps someone else will be able to provide an answer before then.

thanks @jncraton, appreciated.  What I'm interested in is driving the motors at a slightly higher voltage using rechargeables; with either alkaline or nimh AA, the actual driver voltage will be close to 7.x volts.  Using a 2s1p lipo would be an easy (moderate) increase, but I can't find a lipo that would come close to filling the volume (so energy capacity would suffer quite a bit).  OTOH it would be very easy to fill the 6AA slots with 6 14500 protected LiIon cells, re-wired to 3s2p and with a JST to hook the (removed) battery unit up to a balancing RC charger.

however this would be slightly above the lb1836 Vcc abs max of 10.5; so I'm looking for if it would be easier to haywire a different motor controller (unfortunately I can't find any pin-compatible IC's with a higher Vcc tolerance), OR cram in a small buck-boost to handle the 3s2p -> 9v, which would be an even 9v for the whole discharge or a ~30% increase in drive voltage.

TLG was kind enough to send me one of these, so I've done my part and cracked it open to see what is inside. The teardown was fairly easy to do without damaging any components. The only tool I used was a brick separator.
There are a few tabs around the edges that can be depressed to allow the main housing to come apart:

I'm not certain what the purpose of the small rubberized button is, but it is accessible from inside the battery compartment. This may be related to detection of a future battery pack.
The PCB simply lifts out:

On the bottom side, we can see that the main processor is an STM32L431RCT6. It's based on the Arm Cortex M4, can be clocked up to 80 MHz, and includes 256kB of flash memory.
The top side includes the remainder of the components of interest.

For Bluetooth Low Energy (BLE) communication, the Control+ hub uses a CC2640 from Texas Instruments. This is the same chip used by the Powered Up hub.
The motor drivers are LB1836 chips. They are dual drivers, and there are two on the board, one for each pair of ports. These are the same driver chips used for the Powered Up, Boost, and Robot Inventor hubs.
Overall, this hardware is very similar to the other hardware in the current generation of products (Robot Inventor, Powered Up, Boost, etc).

If I may hypothesize about the button. The EV3 had a button that was pressed when the rechargeable battery was equipped, so it didn't complain about the batteries being drained because of the inherent lower voltage of the rechargeable battery (7.2V vs 9V). So perhaps a rechargeable battery solution is also intended in the future for this hub...

@MichaelVerschaeve That was my hunch as well. I'd certainly love to see a rechargeable battery pack for this hub.


text:
Fix Power Functions cable near connector (L motor)
We have a broken cable on the power functions L motor. I've fixed an M-motor before in the engine, but this time the cut is near the connector.
Unlike the M-motor, this connector doesn't have the clips to open.
How can this connector be opened to shrink the wire?
The L-motor has a different connector than the M-motor, it looks like this:

Since there are no visible clips on the connector, it is probably not possible to open it without damaging it. Instead, you could purchase an 8886 or 8871 extension wire and use it to replace the entire cable (assuming you can open the motor).

It doesn't look like solid plastic completely, since there is a line halfway. I will try your solution, after which we won't have a need for the connector anymore, so we can destroy it to see if someone in the future can benefit of the knowledge.


text:
Does LEGO sell a DC relay for Power Functions?
I’d like to use a signal from a (5V) littleBits circuit to control some (9V) Power Functions motors.
Does LEGO sell or recommend a DC relay to facilitate this sort of thing?
If the answer is no, I’d welcome any ideas or experiences in how to do this in a way that’s both easy and LEGO-compatible.

https://secure.sayal.com/STORE2/View_SHOP.php?SKU=248131 is a relay that can be driven from an Arduino, so I would think it could also be driven by littleBits. But it may require more damage to Lego-supplied wires than you'd like, in order to splice it in.
I don't know if it's viable, but could the littleBits circuit move a small arm side to side? If your hand can control the Power Functions using a remote like https://www.bricklink.com/v2/catalog/catalogitem.page?P=58122c01, then surely a robotic arm could as well.
I don't know that either of these count as easy, or Lego-compatible.

LEGO doesn't make something to directly facilitate this type of integration as far as I know. If you can get a PF extension wire, you could cut it and directly make the connections to your driver circuit.

You can drive the motor using the middle wires of the PF cable (C1 and C2).
For what its worth, I would personally prefer an H-bridge such as this one over a relay as you get faster switching and can use PWM for speed control among other benefits. You'd power a board like that using a 9V supply and connect the C1 and C2 power lines to one of the outputs. Your 5V logic-level signals would connect to one set of inputs to control the motor.

I'm not that familiar with H-bridges, but I'm researching the option. Can you tell me if this SparkFun Motor Driver would work just as well as the model you mentioned? (I understand that it may be an H-bridge since it is tagged that way.)

@EJMak I haven't used that exact driver, but it looks like it should do what you want.


text:
What is the power of Lego Powered Up motors (M, L, and XL) and the Move Hub motors?
I am trying to build a setup that includes two propellers that can pitch up and down. I am debating whether I should use two motor to power each propeller and the other two to act as servos for each of the "motor-propeller" set up, or the power of the motor is strong enough that I can use one motor/move hub to drive both propellers and the other motor can be used as a servo. Could you tell me the specs of these thing so I can decide which one to buy or order? Thanks

Philo is one of LEGO enthusiast and he did quite a number of tests with different motors produced by LEGO, which you can find  here. Table below is based on data measured by Philo:

Motor
Torque
Rotation Speed
Mechanical Speed
Electrical Power

PUP M
4.08 N*cm
270 rpm
1.15 W
2.66 W

PUP Control+ L
8.81 N*cm
198 rpm
1.83 W
4.70 W

PUP Control+ XL
8.81 N*cm
198 rpm
1.83 W
4.16 W

PUP Move Hub
4.08 N*cm
264 rpm
1.13 W
3.37 W


text:
How deep can the axle go in the Powered Up L motor?
I am trying to make a MOC but I can't decide how long the axle could be so it can go fully into the motor but not extending out of the other side. Could you tell me how long the axle can go in?

That is only 1 stud deep.
So an axle of 5L always sticks out 4 studs

It's worth noting that it's the same thing with almost all motors that dont have double-sided axle holes (example of double sided axle hole is in ev3 large motor.)

ok SPIKE has 1 stud deep on both (M and L) and the newest motor is 1 stud deep on the top.

@mindstormsboi My guess is that the reason for this is to prevent anyone sticking a 2L axle all the way in, rendering the motor useless

Ok I don't have any of these motors.


text:
How to make a church bell
I'm planning a scene that includes a church bell. It's will need to fit into roughly 10X10X6 space.  It doesn't need to actually make any sound but the ability to swing a bit would be nice.
Here's the image from the scene
I figure I can use a bar, some clips and some stoplights to make the swinging part. Can anyone recomend some parts for the bell itself?

Look at the bell in the Lego kit for Big Ben (#10253). Building instructions are here (Step 276).
The bell itself is made from several round plates and parabolic reflector dishes. It's not hollow, but it could certainly be made to swing.

Wanted to chime in here on this (pun intended): if you want to actually have a bell sound with this, there is an option that most people may not have thought of. Somehow integrating the Lego Duplo Bell helmet and having something striking the lever on the top perhaps when the bell swings - this could be an add-on that should possibly be considered as an option to add some sound which would still be official Lego parts.

Hi Aaron and welcome to Bricks.SE! Don't be sorry for being a new user - everybody was a beginner once. Nevertheless, it is good practice to check the tone and style of any community one is joining, and try to match it in order to fit in. Have fun and play well!


text:
Arduino-izing LEGO Technic - ideas for a car / vehicle to choose
I am starting a project - Arduino-izing LEGO Technic - and now I need some ideas for a car / vehicle to choose.
This project starts out as a quest to find a way to combine the ease of LEGO Technic chassis building with cheap commodity electronics to motorize and remote control it. I am looking for a car / vehicle that is able to work for this. This could be a simple chassis:
https://www.instructables.com/id/Build-your-own-Custom-Arduino-Remote-Control-and-L/
https://www.hackster.io/Notthemarsian/take-control-over-lego-power-functions-ee0bfa
https://www.instructables.com/id/Raspberry-Pi-Remote-Controlled-Car-1/
This should be a part of a robotics workshop and therefore I need a LEGO-based platform for younger kids who grew up with Lego but cannot afford to spend hundreds of dollars to buy power functions, LEGO motors, IR remote, and EV3. Thanks to numerous examples on the net and several and Youtube tutorials on integrating Arduino with LEGO, I will try to start out with an interesting example.
Starting point: the kids should be able to complete this project with a small budget and I hope to incorporate this into my robotics workshop in the future.
The main thing is, I need to have the rear axle to be attached to a single N20 motor to move the kart forward and reverse via a TB6612FNG motor driver.
Front steering can be controlled by an SG90 servo motor.
Remote control should be able to be accomplished by a cheap IR remote/receiver solution based on

Arduino
Zigbee
Bluetooth

I understand that the IR remote hardware (and the method) is pretty hard part to implement and learn about a remote control system so it was a perfect option for this car.
Since this is just a proof-of-concept project and the design follows function - I need to have an idea.
The main question is: which LEGO car to choose?
How about LEGO Technic-8071 - the Service Truck?
What would you suggest?

The Arduino is a great platform for education and getting to the point of doing interesting stuff quickly.  There are a variety of Arduino shields for doing motor control and many forms of wireless.  A later optimization for you might be to make a shield for your students that merges those functions into one shield.  http://www.epanorama.net/newepa/2017/04/23/lego-power-functions-with-arduino/ is another way to do get your Arduino to talk to the robot.

If I were you, I'd try to use a car chassis as simple as possible.
This would achieve multiple goals:

By using a vehicle with the least amount of complexity you can keep the price low.
By avoiding unnecessary parts the students' attention will not be drawn from the topic at hand, e.g. they will be more inclined to listen and cooperate if they are not wondering about or playing with the bucket lifting mechanism of 8071.
The less parts included in the design, the less chances for something to go wrong.
Some space is needed in order to mount the required hardware (motor, batteries, receiver, anything inbetween) and this space is best left open for easy access to inspect, explain, debug, repair, replace, etc.
This approach leaves many ways to upgrade the "final result", either functionally (adding lights, brakes, etc), aesthetically (building a great looking body), electronically (adding additional subsystems like a parking assistant) or mechanically (include advanced steering geometries, suspension, etc) if you or the students wish to do so.
Minimizing the time required to build the mechanical part leaves that much more time for the intended topic of the workshop (the electronics).

Therefore I'd recommend building a simple steered front axle without suspension, a rear axle that is nothing more than an axle and two wheels and slapping both on a large plate or any equivalent flat assembly.

hello dear zovits, many many thanks for the advices and recommendations. These are very valuable and a great asset of food for thougths.
I will take them into account.  Many thanks again !

I'd be tempted to use the Batmobile (76112) design:

Basically, you have independent motors for the left and right wheels. This allows you to steer quickly and easily without the fuss of a traditional steering system.
The Batmobile is $100 MSRP, and can be found on sale. The included motor controller is Bluetooth based, and can be remote controlled via a smart device or custom software on a laptop. Basically, that set meets your needs if you can afford it.
If that is too expensive for you, I'd still encourage you to consider using a similar design using official LEGO motors. It's relatively complicated to integrate off-the-shelf motors with LEGO (I did this a lot as a kid), and the official motors are actually quite cheap these days. You can pick up Power Functions M Motors for $7.49:

That's $15 for the pair. You'd just need to cut off the Power Functions connector and connect the motor to your driver. This saves you the fuss of mounting your motors and integrating them with LEGO gears and wheels.
This is really outside the scope of your question, but on the electronics side I personally wouldn't use an Arduino. I'd probably go with something that has wireless built in, such as something ESP8266-based. Then, all you need is your microcontroller and motor driver for a working system. The system can be remote controlled from a PC or smart device. You wouldn't even need special software on the remote, as the microcontroller can broadcast an SSID and serve up a web-based controller to the connected device.
So then your BOM would be:

2x PF M Motors ($15)
NodeMCU or other wireless controller ($3)
A few Technic beams, gears, axles, wheels, etc ($5+)
Battery box ($2)
TB6612FNG or similar dual motor controller ($1)

You could probably do the whole thing for ~$30.

This is a great idea and simple to execute, but OP has explicitly stated that a driven rear and a steered front axle is required: "The main thing is, I need to have the rear axle to be attached to a single N20 motor to move the kart forward and reverse via a TB6612FNG motor driver. Front steering can be controlled by an SG90 servo motor."
Your input on the pricing and the recommendation for the microcontroller is nonetheless very valuable.

hello dear jncraton - many thanks for the answer with all the hints - very intersting ideas that are worth to follow. This is truely a great place for all brick-endeavours


text:
How to make an object glow in Studio (BrickLink)
Is there a way to add glow colors to objects or parts in the BrickLink's Studio?
The thing I am trying to do is to make a glowing light bulb so I can have it as a light source in enclosed areas (Like any room) and have its impact on rendering (POV - RAY / Photorealistic Render (Eyesight)).
Is it possible? Is there any other lego designing software that supports this?

Looks like I solved my problem myself.
Here's what I did:
I exported the Lego model as Collada (.dae), and imported it in Blender. Selected the material and changed Diffuse BSDF (Maybe changed for you) to Translucent BSDF (for cycles only), selected Volume as Emission and rendered.
Cheers

Blender hangs when I try to import the Collada file. Any idea?

@Alec This sounds like an other type of issue. I would suggest ask this question on https://www.superuser.com/


text:
Power from single XL-Motor to both rear and front axles
I have a single XL motor and I would like to make my small car a 4WD one.
Currently, it is just front-wheel drive.
Any good instructions on transmitting power to rear wheels as well?

How that can be done depends heavily on the design of the car, so no general instructions exists. I simple cases, and very generally it's something like: add a gear to an axle driven by the motor, add another axle with a gear that connects to the first, and goes from that point to the back axle and transfer power to that. If there's a differential on the back axle, that's probably where you want to deliver power.

While @Henriksupportsthecommunity provided some generic details I find this question rather broad. Please edit it to ask some specific question you are facing with your 4WD implementation. One advise - XL has high torque, so brace everything as much as possible not to damage your gears and axles.


text:
Where can I find the value of this seemingly rare MEGA BLOKS tree and whether there are additional parts?
I am looking for a value on this MEGA BLOKS item and whether there are additional parts to it.  I have searched AM05829 AND AMO5829 on internet, ebay, and etsy and have found nothing.  I seem to be able to attach only one photo, but the previous item # is stamped on the tree base.

Looking for the tree by descriptions "mega bloks cartoon tree" and "mega bloks happy tree" I came across this listing with photos of the set. It's from a Dora the Explorer set with 44 pieces.

You are so-o-o awesome!   THANK YOU!!!


text:
IR remote 8879 - cannot control speed of the motor
I got the 7938 train set for my kid.
I hook up the battery to the receiver and try the IR remote 8879 with it.
The motor starts running/spinning, but I can not control the speed with the orange "joystick" knobs on the remote.
Whether I turn the wheel clockwise or CCW, the speed just ramps up (to the maximum speed, I guess) faster and faster.

Fresh batteries are installed
Same channels are selected (also tried all four channels)
Switched between red and blue connections

Any ideas why this may be?

For what it's worth - I have seen that happen a few times with my remote as well (albeit just on one of the joysticks iirc), but couldn't reproduce it just now with several combinations of IR receivers (both v1 and v2 fwiw) and motors. I've always suspected a faulty contact, but have never found out for sure.


text:
Identify this T-shaped part
Seems to be used for making differential gearboxes, cars, and GBCs.

It's used for many things!  It's great at joining beams together at perpendicular angles.  When disassembling technic sets, these are often the most challenging to get through.

It's difficult to find a modern technic set that does NOT contain this element, it's ubiquitous...

Vic, welcome to Bricks.SE. Does your piece take an axle or a pin in the direction we can't see from the angle of the picture?

Thank you. It takes a pin

Here you have the Bricklink link to the part: https://www.bricklink.com/v2/catalog/catalogitem.page?P=63869#T=C

it is named Technic, Axle and Pin Connector Perpendicular Triple on BrickLink. The ldraw/bricklin item id is 63869. The Lego design id is either 63869 or 42191, indicating that there have been at least two moulds.


text:
Camera for Spike or Mindstorms for Streaming
I have made a few EV3/Spike robots that can be controlled remotely. They are controlled by either a PS4 controller or using a dashboard I built on a website. I'm running Python on the LEGO. However, at the moment you have to be in the same room so you can see the robot. I want to add a camera to the robots and stream the video to a website. Anyone know of a camera that would do this?
Edit: I was hoping to connect the camera to the EV3/Spike brick. That way I can use Python to handle the stream and eventually make the robot drive autonomously.

Not turning this into an answer, since I have no personal experience (someone with actual experience will probably get to that). But GoPro camera's are a common choice. Look for eg. "gopro lego mount" in your favorite search engine to find several solutions for mounting a GoPro camera onto a lego creation (some using custom lego bricks).

Oh, I don't think the spike hub has enough computing power to live stream video. It's a 100MHz CPU, and the ports are limited to a bit more than 100KiB/s; those are serious constraints. It's possible to find third-party EV3-compatible cameras, but those are meant for on-board artificial vision and video recording, not for FPV / live streaming.

You probably want to look into suppliers for copter drone parts - the kind that RC hobbyists attach to drones or RC cars to fly/drive from a first-person point of view. These are called FPV ("First Person View") cameras. They're already designed to be light, compact, and battery powered.
I don't want to be partial to any brand or model, so I suggest you search for RC FPV cameras and/or drone fpv cameras yourself. See also "What should I look for when choosing a FPV camera" in the drones.stackexchange.com site.
For the full setup you'll need:

A camera. These typically output analog composite video.
A video transmitter. These input composite video, and convert it into radio waves.
A battery, to power the camera and the transmitter.
A video receiver. These take the radio waves and output composite video.
A way to watch the composite video, either

An analog TV monitor with composite input, or
A computer with a composite video capture card (which can take the form of a PCI/PCIe card, or a USB dongle), or
A specialized unit (RC receiver, VR glasses)

The camera+transmitter and the receiver+capturer might be in the same package (read "inside the same plastic box", sold together as one unit), but you should be aware of all the system components. If your goal is to provide video in a website dashboard, you probably want the video capture card and the webserver in the same computer (I'd recommend motion for the software bit, since I've used it in some raspberry-pi projects).
I'm afraid any further detail would be off-topic for bricks.stackexchange.

You could use a smartphone to do this. They are lightweight and have a camera and Wi-Fi all in one package.

This might work, I did consider this. I need the video feed to go directly to a website feed. I could use Twitch or something, but the six second delay or so is too much. Is there any existing tool to stream an iPhone camera to a website feed?


text:
Fix Lego M Motor - The hooks aren't budging
I have a Lego M motor that is broken. I'm following the instructions here to try to fix it but the little tabs that hold the plastic frame together just won't budge no matter how hard I'm pushing them (4:20 in the video).
Does anyone have any suggestions as to how to take this thing apart? I'm deforming the plastic on the tabs since I'm pushing so hard with a screwdriver with a star head on the end and they look terrible now.

Related: https://bricks.stackexchange.com/questions/10367/what-is-inside-the-lego-powered-up-m-motor . You have removed the bottom phillips screw first, right?

Yes, of course.

In the comments of that video, the author responded to a similar issue : instead of using a screwdriver, you might jiggle the housing from side to side, while pulling, to get it to separate. Haven't tried this myself. All credit to the author of that video if this works.

maybe jncraton need to be an answer for you


text:
EV3 classroom cannot create New Project

EV3 Classroom V1.5.0
Windows 10

I run a lab of 24 laptops running EV3 Classroom v1.5.0. Over the last week, more and more computers are unable to create new projects and/or open existing projects files.
When creating a new project clicking on the "New Project" button causes the spinning wheel icon that doesn't move on to a new project created.  If attempting to load an existing project through "File>Open" the Windows menu disappears but no Open File dialog is created to select the file.
Any suggestions or additional data needed for help me?

Does it work if you upgrade to the latest version? v1.5.3 is the latest available for Windows from here at the time this comment was written.

You could also try checking for recent Windows updates and try reverting those to see if that broke something.

Will do so @DavidLechner, my tech is offsite for the day but I'll try and get the IDE updated. Reverting windows updates isn't something we can do but I'll check and make sure those units don't have any updates pending.


text:
What electronics are inside the SPIKE Prime angular motors?
Is there any information available about the internals of the SPIKE Prime and Robot Inventor angular motors?
What Hall-Sensor is used by the SPIKE motors?
To be more precise: I'd like to get information about the internal components of motors in a way similar to this teardown of the SPIKE Prime Hub.

There's some spec sheets at https://education.lego.com/en-us/product-resources/spike-prime/downloads/technical-specifications - does that suffice?

any chance to get the value or part no. of the hall sensor?

@AbdElhaleem In the answer the last sentence is this: "The part number on mine is BCZK 116." Does this answer your question? If not, please ask a dedicated question with the necessary details.

Here's what the part looks like from the outside:

The first step to opening it up is to remove the cover over a section of the drive. Note that this process is likely to cause permanent damage to the part as it requires prying and bending.

We can now slide the gray back cover off.

The PCB is clipped in at the front, but with some care we can separate the gearbox from the motor.

The gearbox houses a pair of bevel gears. The gray one that is part of the drive shaft is 11 tooth and the smaller one is 9 tooth.

With significant force, the drive shaft can be separated to remove it and reveal the magnet that is used to sense drive angle.

Moving back towards the motor, we find a double planetary gearbox similar to the one found in several motors without angular drives.

The motor itself is soldered to a PCB. There's nothing other than traces on the side facing the motor, so I haven't bothered to desolder it.

The main microcontroller appears to be an STM8S103. My part has the following part information:
S103
PHVG
939Y

The other significant visible part labeled 509R is a thermistor that serves to put a hard limit on motor current.
Viewed from the other side, we can see the hall effect sensor that is used to detect drive angle. The part number on mine is BCZK 116.


text:
How can I build a human-scale Lego gun?
I would like to build Lego projectile weapons. Are there any designs available? Can one make an amunition magazine and self-reloading mechanism? Should I use rubberbands as ammunition or are there designs that fire Lego bricks?

You'll shoot your eye out!

There are some Books available that include building-instructions (i don't own one of these, but i would choose the most current):

The BrickGun Book (Book released in 2013, site has occasional updates as of December 2018 with more instructions)
Badass LEGO Guns (December 2010)
Weapons for LEGO Lovers (February 2009)
as Joubarc said the at least 4 years old Forbidden LEGO (July 2007)

to answer your question about magazines/reloading mechanisms: see this youtube-video that shows such a mechanism in detail (although it's a bit hard to perceive details).
in addition the book about LEGO Technic Simple Mechanics might also be interesting for you, if you want to try building a own gun instead of just "copying" from a detailed instruction.

There's a new one out: "The BrickGun book" - see this review on Brickset

The book "Forbidden LEGO" has some, and you may also want to check YouTube on the subject

I own this book and it's fairly outdated. The 9V 2-switch Battery box required to power the 'gun' is a rare find. It was last sold as part of the 4094 Motor Movers set in 2003

It's also worth mentioning that the model required modified and non-Lego pieces so it wasn't fully brick-built. Youtube is a good place to look for inspiration.

There is a book called "LEGO Heavy Weapons" by Jack Streat which is published by No Starch Press and can be bought for about £15 on Amazon.

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


text:
What is inside the "weight element" brick?
I own a few bricks that contain a weight inside of them. 52g according to Lego.

What exactly is inside of these bricks that makes them heavy?

Are you talking about these lego train weight parts ?

I did the unthinkable!  ...I had to know.
I opened one of my two weighted bricks.  One of the two ends has a glued-on cap that I've cut around using a utility knife.

The piece of metal it contains fits almost perfectly in the cavity.  I don't know metals but it has a rainbowish kind of sheen to it.  Here's a close-up:

I'm now reassembling it back and super glueing it.

+1, for defacing a LEGO brick to provide an answer. I imagine you could weigh it to find it's mass.

Since when is defacing a LEGO brick worth +1? Heretic!

Makes sense that these would be galvanized steel since they were often used to balance the floating boats (e.g. 314, 4005, 4010, 4025, etc.) and could be reasonably expected to get wet and rust leaking out of the brick would look weird.

I literally gasped when I saw this.

I don't know whether to upvote this answer for being correct, or downvote for cutting lego bricks apart. This sort of experiment would never get past the ethics panel in my household.

I have one that had been opening itself by the side for like... forever. And I didn't use any violent mean for it to reveal its shiny insides. Note that the side can be clipped back. I thus always thought that this was meant to be possible to open/close this container.

I did this back in the mid 90s because I too had to know. Now that we all know, I wonder if you could replace it with something even heavier. Are there any safe denser metals that aren't too expensive? A lead alloy maybe? Just under 2 ounces isn't all that much weight.

@l008com Go for tungsten. Almost twice as heavy as lead without the health hazards

I had two of these bricks in red, one is broken (one of the side-caps dropped off): there's just a piece of galvanized iron/steel in it.
My blocks were bought about 19 years ago, so maybe they changed the weight to an other/cheaper material in the meantime, but I don't think so.

This seems like it's correct. I'm going to do what Zhaph said and test it with a magnet.

i'm not 100% sure it's iron/steel, but it pretty much looks like because it's galvanized, wich won't make much sense on other metals. i'm looking forward to the results of your magnet-test.

I'm fairly sure it's one or two pieces of iron, but I would need to check with someone who actually opened one. You can easily check that it's a ferrous metal if it attracts magnets.

Non-ferrous metals aren't magnetic... so a lack of attraction doesn't rule out the possibility of a metal being used ;)

Indeed, I oversimplified it, I guess I'll edit that in. But magnetic attraction will confirm it's a ferrous metal, and since I was pretty sure it's iron (as confirmed by oezi), I didn't want to bother thinking about other metals.

Lego magnets stick to them just fine.  It takes two magnets to lift one brick.

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


text:
How to start with LEGO Technic?
I have bought myself the LEGO Technic set 9393 Tractor. I like the model and I want to dig deeper into the LEGO Technic universe. I am not focused on building pre-designed models (although I enjoy it, and it would be a plus), but I want to have a decent set of Technic parts, such that I can build models on my own. So what is the best way to get a basic set of bricks:

Buying some sets and taking the parts from the sets? (rather buy a big set or several small ones?)

Buying used parts in bulk?

Are there non-model Technic sets, similar to the traditional Lego, for which they have door sets, wheelsets, etc.?

I know this question might be a bit broad. So let me add that I do not necessarily want to build motorized models right away. Also, I do not plan to build huge models, more in the size of the 9393 model.

I've bought bulk 2nd-hand bricks, includes bricks with holes & gears of technique. Can start by joining 2 castle together as they use technique bricks for that. I looked at instructions on line, but I have not the right parts.

Here are the two things that I would recommend:

Get yourself a big set if you have the budget for it. These will have a large variety of pieces and once you've built the models from the instructions you'll have a good understanding of a lot of different building techniques.
Watch eBay or similar sites for large lots of Technic parts by the pound. These can be a little hit or miss, but the price per piece is far lower than most other ways of buying parts. Keep in mind that prices tend to be higher around the holidays.

There used to parts packs for Technic like what you are describing, but I believe they were removed now that pretty much everything is available from Pick-A-Brick. You can also get any parts that you want from bricklink.com, and if you don't mind used parts, this can be a pretty affordable option.

I support the idea of getting a big set first.  Personally when I got back into LEGO Technic (for the purpose of using it with MindStorms) I got the 4x4 Off Roader (#8466, 1134 pieces)

How about ideas ? Any book to recommend ?

I have to say I did the opposite and bought loads of small kits first and then larger kits later, however I did do a lot of research on the net and there are plenty of good books for reference material on individual mechanisms on Amazon (without having to buy lots of useless pieces for only specific functions on one kit only – can be quite expensive option).
Ebay can fill up on specialised hard to get pieces and in a variety of colours too- although one has to wade through most of the junk available to find what one needs and it also depends on what you want to build? Bulk buying is a good use of this method – pick a brick can be expensive but the quality of the new bricks are without question.
Pinching plans of Technic kits from LEGO directly or from other fansites, is a good idea (with permission) to expand your knowledge of all the possibilities out there, too.
Finally, I find that technical manuals from real machines are really good for inspiration like those cutaways from plane books are really useful or car repair books etc – so do your research first and ask around – lots out there...

Coming to this late, as I am in the same kind of boat.
Options might be different in 2014 due to newer options for models.
I'm trying to find a nice few sets that can cover me for building almost anything else. Using rebrickable, adding models to a set and then looking at other Technic models (both official and MOC) will give you an idea of what sort of bits you want next. Also gives you suggestions on models to buy to up your % match.
8043 seems like a good set, but has 4 piddly M motors, which I guess is okay on top but on its own is a little lame, also the price for this retired model has gone INSANE.
So far I have gone with these three...
42030 Volvo L305F Wheel Loader
Got it for £131 new, has 2 remotes, various sized motors (including steering servo), actuators, bucket and some rather large wheels.
42009 Mobile Crane
Seems to be the largest model you can get for a good price (£105), has the most pieces in any Technic model so far (although apparently half of these are just pins!) but this brings another motor and battery box (sadly just 1, but still), diffs, a bunch of wheels and obviously lots of pieces.
I already own a few small (9391, 42001) and a mid sized model (80690, buckets, wheels small LA)
42028 Bulldozer
Recently bought this for £25 as a present, really good price, just been looking at how much track is to buy on its own and its not much less than this. Although its ~14 short of building the 8043 (and I'm guessing short of a lot of MOCs) but its a start, at least you get extra parts. Could buy 2!
Hopefully they, obviously large will be a good start.
Ideally what I personally want next is:

A proportional remote, the train sets include these + the "smaller" battery box that a lot of people use, although the big designers often have the rechargeable boxes, the 6xAAA are drop in replacements (mostly, assuming they haven't made use of the reversal pin). Im not sure I will do this though as I don't think the lad will like me gutting a train (and I don't want to stretch to two!)
Pneumatic kit, no sets seem to have a lot in them. ile9os on ebay has a VERY nice "pro" set. I wish they had more than 1 mini-pump in the collection, sadly to get 3 (to make a total of 4) from bricklink the price goes up when you have someone that has a quantity you want (bricklink is kind of a pain for that).
Steering kit, there are a few different types so looking at smaller models for these.
Springs, I'm keeping an eye out on deals of smaller Technic non motorised sets for these.
Wheels, but I'm going to resist buying them on their own though as you can easily get these on smaller models, and will eventually be overrun with them (as I am with non-Technic LEGO since I decided to buy a batch lot and later on... I have too many!)
More clutch gear, the above has some in but would like more, the crane has a lot in because it has one motor for all the functions. Service truck seems to be another and has some pneumatic kit - personally don't like that model though and I'm not sure about the price (still watching)

42005 seems to be good for steering ball joint(x2) small springs(x4) "steering arms"(x4) steering rack(x2) knobwheel(x2). All that would cost you around £20.45 on ebay at a quick glance, and has sold as low as £23 on amazon (currently £33, I'm going to hold out for sub-£27) and it has 327 parts. You can see why people buy and part out to sell.
btw for the likes of Amazon, get onto camelcamelcamel and set a LOT of "crazy" price alerts and sit on them for a long time.

LEGO Education still sells a Pneumatics set https://shop.education.lego.com/legoed/en-US/catalog/product.jsp?productId=9641&isSimpleSearch=true


text:
Homemade methods for interfacing a Hobby Servo with LEGO bricks
I'm looking for a non-destructive way to structurally attach a standard hobby servo with LEGO bricks.  I'm interested in answers for either Large, Medium, or Small size servos.
I'm using LEGO Mindstorms/Technic bricks to prototype all kinds of robotic projects and I often use non-LEGO parts for the electronics (e.g. Arduino, Servos, LEDs, ...).  I'm always trying to find better ways to integrate those non-LEGO parts without damaging the LEGO bricks.
I'm aware that there are some commercial adaptors available on the market but I'm interested in creative homemade solutions (low-cost to no-cost).
For example: here is one way to attach a medium-sized servo to a LEGO Technic beam:

At first I thought you were speaking of the electr(on)ic part of things, but now I think you may rather be after the physical assembly to LEGO parts - right?

@Joubarc Yes I'm talking about the physically attaching servos and LEGO bricks together. I'll clarify and add a image to help.

The best solution is to create custom LEGO-compatible bricks that your servos (or other parts) fit into. This can be done by:

modding existing bricks with knives, glue and other tools
building bricks from other material (wooden LEGO, formed with Fimo/Sculpey...)
building bricks with a 3D-printer (for instance see the LEGO category on thingiverse). There are online services to print your designs if you don't have a 3D printer (yet ;-)

Each strategy is worth another question here at bricks.SE.

To add to this answer, I would also suggest looking at The Free Universal Construction Set. While they don't provide anything for integrating legos and servos specifically, there's a lot of examples of how to integrate Legos with non Legos components (some of which might make integrating a servo easier.)

Depending on your rigidity requirements, I've found double-sided tape to work well.
It's cheap and found in many general goods store. The servo itself can be taped and supported on all four sides and/or the bottom to many types of lego brick surfaces.
You can also use double-side tape to mount a lego surface to a servo control horn. That provides nearly infinite mounting flexibility. However, the control horn attachment will not be very rigid or support a lot of weight without an additional structures to support whatever is actually moving.
When finished, you can just peel the tape off.  (...which is sometimes easier said than done.)


text:
Where can I get replacement cables of this kind?
What I'm looking for:

This is a 4.5 V cable which is part of an old set I once had. I don't have any parts number, but I know this comes in different lengths.
Google told me about bricklink.com and I've searched there but didn't find it.

Note that it's possible to undo the screws holding the wires into the plugs and replace the electrical wire part with whatever you like - longer, shorter, pretty colours, whatever you like. The main thing is making sure you don't lose the screws.

Thank you @M(something?). I'm handy with a screwdriver so fixing ones myself are no problem - if I had enough parts. I'm looking at a bag of LEGO from my own childhood and most cables are incomplete... (yes, even missing the pins and the screws) so I need complete replacements. Maybe 11yo me wasn't good at taking care of small things. Maybe that's why I never had a hamster? :-)

darn, I hoped the photo was of your cable. I had the same problem, but took the motor into an electronic supply place so I could try all the likely looking plugs and eventually found some. They were much cheaper than official Lego ones :)

That photo is my cable. But it's the only complete one I have, and not in best condition either :-/

This is an Electric, Wire 12V / 4.5V.
They can be found here:
Catalog: Parts - Electric, Wire & Connector
Just find the right length.

link is now updated


text:
How to run "Power Functions" devices from an electric wall plug?
In this video showing an example of Great Ball Contraption (GBC), we can see (at 1:35) that some train's powers are used to run Power Functions (PF) motors:

That must be more convenient than having to change batteries after several hours.

What parts are involved, from the electric wall plug to the final motor?
I guess that the following parts are used:

Power Adaptor (70931) plugged on wall plug, that provides current through a wire connected to…
Train Speed Regulator 9V (2868b) that outputs current through 9V plugs
a Power Functions Extension Wire connected on 9V plug that provide a Power Functions-specific plug (8886)
any Power Functions motor in the module, e.g L motor:

Are my guesses correct?
If I remember correctly, I have already seen in some videos that the Technic Control Center II (2840c02) was used in place of the Train Speed Regulator. Does it work too?
The Train Speed Regulator 9V are Technic Control Center II are incredibly cheap, are they the cheaper way to power devices from an electric wall plug? The Power Adaptor is relatively expensive, but it's probably possible to find a cheaper and compatible adaptor.

Hopefully somebody will be brave enough to try it.

@chicks We have a better view of the wires in this video, I'm 99% sure that I identified the parts in my question. A confirmation would be nice though.

It is pretty much the most used setup in Europe for GBC. Side note: if you need to power specific PF electronics such as the step motor or an IR receiver, the conversion cable won't be enough as it  only provides power to PF C1/C2, not 0V/9V. You can however add an empty battery box to power these too provided it's setup correctly - see https://www.youtube.com/watch?v=0j8QXHI6EaY for example for explanations

What you describe is indeed the most common way to GBC modules, but it's worth noting that one adaptor+regulator can typically power more modules (it depends on the modules), sometimes only one end of the extension cable is used, when placed on the regulator, it effectively provides a power functions "plug", and if you want to power more modules, the wiring can get a little easier to handle, when every module is essentially connected to a regulator.
Another option is an NXT with the official rechargable battery mounted and an adaptor plugged in, and then of course NXT cables to an NXT motor (I don't remember if NXT->PF cables exists, but NXT->9V cables does and you have mentioned that the PF extension cables can attach to 9V). I have also seen modules with an RCX, I think that has a plug for an adaptor directly, but I'm not sure, I don't think I've seen GBC modules powered by EV3's yet, but there's probably a solution. - Probably more expensive, but having an NXT in a module allows other possibilities, especially if you also put in some sensors.
As Mr. Shiny and New 安宇 mentions the rechargable battery box is a third solution.
All of these solutions have the advantage that they only use official unmodified LEGO parts.

I just happened to finish a homemade solution to this problem a few days ago — so while I can say this works, it isn't exactly long-tested. I made an adapter to connect a 9V power source to the battery contacts in a regular Power Functions battery box.

The trickiest part is making the connection to the positive terminal of the battery box (which is a recessed flat contact as opposed to a spring). There are lots of ways the details of this could be handled, depending on the materials and tools available. I used two AAA-to-AA battery size adapters that I had on hand — for this purpose, they're just battery-shaped plastic objects with contacts on the ends. One of them has only the negative end connected, and the other has only the positive end.
(Perhaps there are LEGO parts that could be used instead? 2×2 cylinder bricks are a bit too large…)
Hook up these two “dummy batteries” to your power adapter. (If your power adapter has a barrel plug and you don't want to chop it off, that may be the because you need a matching jack. I just bought a surplus adapter and cut the plug off.)
The two “batteries” go into the “endmost” slots in the battery box — these are the two that are closest to (negative end) and farthest from (positive end) the switch, paying attention to the zigzag shape of the two sides of the box. These are the two slots that are actually wired to the switch and output; the rest are just to make connections between six separate cells, which we don't need.

Materials used in this particular build:

Two AAA-to-AA adapters, with holes made in the sides for the wire.
Wooden dowel, to fill out the interior space, with a groove cut in the side to make room for the wire.
Spring, at non-contact end.
Ordinary brass thumbtack, pressed into the contact end of the dowel.
Wire, soldered to the inside of the tack.

There are surely much less complicated ways to do this, such as not bothering with the plastic adapter, though then you need to be more precise about making things the right size.
Pros of this method:

Cheap if you have the right materials on hand.
You get the reverse/off switch and overload protection circuit that's in the battery box (unlike, say, cutting a Power Functions wire to make direct connections, which would also work).
No bulky speed control box if you don't need it.
The same adapter can power an old-style 9V battery box, a Mindstorms brick, or anything else taking 6 AAs.

Cons of this method:

Not an official LEGO power adapter.
Might be stressing the battery box due to long-term higher voltage than AA batteries under load.
You get no speed control (if that's something you care about).
Ugly; you have a battery box with the covers taken off.

I've heard that the rechargeable battery box sold by LEGO can power a motor while it is plugged in and charging. If your motor is in a stationary position, this could be sufficient.
I've also read, in customer reviews on the LEGO website, that it is possible to daisy-chain power-function devices to the old 9V motors, however, I'm not quite sure what is required for that.

Thanks for your answer. The rechargeable battery box is really expensive, the 2868b regulator and 2840c02 are 30 and 5 times cheaper, so I found them more interesting. About daisy-chaining, I asked a question about this: http://bricks.stackexchange.com/questions/7939/does-the-lego-power-functions-extension-wire-8886-work-in-both-directions-be If it works for old 9V battery boxes, it should work with the big regulators too.


text:
How can I control the speed of motor using gears?
Can anyone tell me how to use gear wheels to modify the speed of the M motor in the Power Functions set 8293?
I know I could use the IR receiver, but I need to have a fixed slow speed on a static unit that will power a non-LEGO moving toy. I need a slow-turning axle.

Sariel's tutorial is one of the better ones, and his whole web site is worth while. The Eurobricks Technic forum also has a list of tutorials thread that you might find helpful.
Sariel starts very simple and ends up with a discussion of what makes different variants on some of the Lego gears effective...


text:
How to build a flywheel slider crank piston pattern with LEGO Technic?
I'm not sure of the name of the pattern, feel free to edit the title if you have a better name for the pattern commonly used in engines. I was just wondering if anyone has built this specific pattern in LEGO Technic. The piston part is not important, I only need a flywheel that takes a crankshaft forward and backward repeatedly. Does anyone know some common patterns for this, with a large radius on the flywheel?

Here's one simple way to accomplish this using just basic parts:

This isn't quite a pure Technic example, but that construction is almost exactly what was used on the steam cylinders on Emerald Night:

Depending on exactly what you are trying to do, there are also some specialized parts that make building decorative pistons simple. For example, here's the V8 from the 8880 Super Car:

There's also the much earlier piston design on 853:


text:
Pattern for vertical motion using LEGO Technic
I have a motor and some other components that move a machine vertically on the ground. Inside the machine I need to raise a part by 5 cm, up and down.
Are there some common patterns that can move objects vertically (lift) using LEGO Technic? Torque comes from a motor powering gears.

It seems from your question that you want to convert a continuous circular motion from the motor into an up and down motion with a range of 5cm - is that correct?

You can use a mechanism like this:

This is a mechanism that converts circular motion into reciprocating motion. You may need to alter the design for your needs regarding height difference, stability etc.

You can accomplish this using gear racks (3743):

You just have to create some type of channel that allows the rack to slide vertically, and then set up a gear to mesh with the rack. You can do this however you like, but here's a quick example that I built to show you what I mean:

if only the gear racks weren't so hard to come across!

Indeed. They're fairly affordable on Bricklink, though: http://www.bricklink.com/search.asp?colorID=86&itemID=697

The gear racks were quite common on the early Technic cars with steering.


text:
Can I buy replacement bags through Lego?
Several years ago I bought the Millennium Falcon through AliExpress for my son. He began putting it together but I think he was a little too young at that point and he abandoned it. Now he wants to build it but we seem to be missing two entire bag numbers. I'm fairly sure all were there originally and we've misplaced them. Do the bag numbers for the AliExpress "Lego" match those for the actual Lego? I'd like to see if I can buy replacements from Lego but I don't know if numbers 4 and 15 in my son's build are the same as they would be for true Lego. Thanks!

Have you actually asked Lego customer service? They're an email away and will give you a definite answer.

I guess I feel kind of bad asking them since I didn't buy their product, but that's probably what I should do.

Perhaps you can be more specific which clone brand and which model you've bought. AliExpress is just a platform offering several clone brands...

Lego customer service will send you missing parts free of charge as long as they still exist. I was surprised that I couldn’t pay for them. Not sure about missing bags.

If they do sell complete bags (don’t know if they do) then they make more money selling it than not selling it, so no need to have a bad conscience. If they give them to you for free and you feel bad about it, donate some money to some good cause and if possible hide the receipt somewhere inside the build.

I don't know what AliExpress sells, but for genuine LEGO sets customer service typically does not store the bags that are in sets, but if it's not too old, they probably have all the parts (possibly except minifigures from licensed - like Star Wars - sets). But they probably won't have an inventory of the bags, so you'll have to make a list of the individual parts - that work is yours, and the resulting list might be quite long.
So if you bought a genuine LEGO set, and "several years ago" isn't too long, you might be able to order the parts - parts that are in active (i.e. currently sold) sets, should be in stock, parts that are not is where time becomes an issue, it also matters how many copies they've had to send out to others, so it's impossible to say what the time limit is - and they've made several versions of the Millenium Falcon, so we can't use that to guess.
I don't know if customer service will even handle a request like that, but if they do it will probably be expensive. And with the list of parts it might be cheaper to look at Bricklink for the parts.

If I were in your shoes, I'd first check if the off-brand Falcon is really the same as the official one. Use the building instructions and - if provided - the parts list to compare the two. If they are different, then all bets are off.
If they do match (aka it's an identical, therefore unauthorized bootleg copy), then it's quite straightforward (but time-consuming) to compile the list of all missing parts, which can then be ordered from second-hand sellers or Lego's own Pick-a-Brick service.
Depending on the original price you paid, the cost of the replacement parts and your valuation of your own time, it might not be that bad a deal compared to the going price of an authentic Millennium Falcon. But keep this in mind the next time before ordering non-LEGO sets, that part of the official price goes to ensure no such thing happens to any customer.

I think OP or his young son lost two complete bags with parts.

@gnasher729 yes, that's clear. What's not, is whether the bags of the counterfeit set have the same contents as the ones from TLG, or even if the set is identical. If some parts have been added, removed or exchanged when converting the official set to the off-brand one, even the two missing, sealed original bags might not help.


text:
Connecting a Lego PF M motor to computer
Can you connect the Lego Power Functions M motor to a computer with USB?

TL;DR: It's not trivial.

First, let me quote the pin-out of a PoweredUP (PU) connector from https://bricks.stackexchange.com/a/10365/13403 :

Pin 1 - Motor
Pin 2 - Motor
Pin 3 - GND (0v)
Pin 4 - VCC (3.3v)
Pin 5 - ID 1 (UART TX for active devices)
Pin 6 - ID 2 (UART RX for active devices)

Assuming that you have solved the physical part of the problem (i.e. you can reliably connect cables to those connector pins), now the question becomes "How to supply 3.3v", "How to drive a PWM signal" and "How to read data from a UART" from a computer via USB.
In order to read data from the UART (which is used just to know which kind of motor is attached), you'll need a USB-UART converter, such an inexpensive CP210x or a PL2303, which looks like this:

You'll then need to connect the TX and RX pins from the UART to pins 5 and 6 of the PU connector, and you should be able to send and receive data using serial console software. You can find details of what commands you can send (and what responses you can expect) at https://www.philohome.com/wedo2reverse/protocol.htm .
(Note that these kind of USB-UART boards usually provide you with the needed 3.3v line)
On the other hand, there are no off-the-shelf USB-to-PWM boards. The closest I'd get is using an Arduino (or a similar electronics prototyping board, e.g. RPi zero, ESP32) to drive the PWM signal to the motor. It'd be possible to program the Arduino board in such a way that it can receive commands via USB and change the PWM output accordingly

Another possibility (since we're getting into electronics anyway) is to eschew USB altogether and rely on a computer platform capable of driving PWM signals, e.g. the Raspberry Pi (or similar single-board computers with a compatible GPIO block suck as Pine64's Rock64), plus a so-called "Build Hat" shield:

See also the documentation for the "build hat".
Note that the shield is pretty "dumb", and doesn't contain any electronics. You might as well connect the PoweredUP (PU) pins 1 and 2 directly to the GPIO block (one pin to GND, the other pin to a PWM-capable GPIO). Then read some documentation on driving a PWM GPIO through micropython.
EDIT: this question is related to "PF stuff" and not "PU" because the plugs are diffrent but you can buy a PU to PF adapters like this one

"Non trivial" indeed.

Contary to this post, the build hat does have electronics on it (on the bottom of the PCB so they don't show up in most product shorts) including a rp2040 microcontroller. The fifth and sixth pictures on https://www.adafruit.com/product/5287 show the electronics.

Interesting - the board seems too clean from the top. I'll edit the answer later to reflect this.

Since both the connector and the protocol are different, it's definitely impossible to just plug the motor into a PC. If you allow for using a converter which would use a custom electronic board to convert between the USB and LEGO PF interfaces, then it is definitely possible - but I don't think this custom electronic part exists. There is one adapter on the market, but it is "dumb", as in merely connects the power pins, resulting in the motor turning continuously with full throttle. If you want to control the motor from the PC, you need to get busy with electronics and software.