text:
How can I create custom EV3 blocks (developer mode)?
What do I need to create custom blocks and in particular the VIX part?

Would be great if someone could create a MQTT custom block.

You only need the official LEGO MINDSTORMS EV3 software.
LEGO provides a "EV3 Block Developer Kit" on the MINDSTORMS downloads page. This contains some minimal instructions on creating blocks. It also contains an older version of the EV3 software.
However, I have found that any version of the MINDSTORMS software can be used in "developer mode" by creating a file named MindstormsEV3.ini with the following contents:
<?xml version="1.0" encoding="utf-8" ?>
<Tokens DeveloperMode="True" />

Save this file in the directory where the software is installed, e.g. C:\Program Files (x86)\LEGO Software\LEGO MINDSTORMS EV3 Home Edition\, then start the software.

This works. Drop a Block to a Program and double-click the block to inspect its .vix internals. Now you are in LabView edit mode.

When trying to save a .vix -- even a new Project and new .vix -- I get a "Unexpected error during save. Is the file read-only?". (Win7 SP1. file permission should not be the issue).

With a fresh copy of Lego Mindstorms Home Edition or Education, the error went away, but the save action is not saving the edited .vix back to disc. Any ideas?

Use Export... on the Developer menu to save the .vix file to disk.

For input output you can use the OtherFiles Folder> EV3 and import the PBricks primitive.


text:
EV3 Wired Brick to Brick communication
I'm currently working on a project for my intro to engineering class.
As it stands now, one brick is running a LabView program to intake data from a 'barcode' and another brick runs a  Matlab program that reads a marble with the color-sensor, and can pass or deny the marble.
I'm having an issue in making the bricks communicate with each other. Because there will be many other bricks in operation where this project will be tested, BlueTooth communication would be unreliable.
From reading that I've done, there might be a way to perform hardwired communication by linking sensor port 4 of both bricks together, but I'm not sure of the specifics.
Both of the bricks are EV3, updated to the latest firmware.

You say Bluetooth is unreliable for your application. I'm not so sure it is. Have you considered a mesh network?

The reading you have done about connecting input port 4 is for the NXT, not the EV3. The NXT has a special feature on that port for RS485 serial communications. This is not present on the EV3 bricks.
The EV3 bricks are designed to be able to be daisy chained via USB. There are "Message" blocks in the EV3 software for sending messages from brick to brick. I'm not sure about LabView and Matlab, but I suspect that have a similar block/function for sending messages.

source: Stack Exchange

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

authors: นายพัธรนนก์ ชัยเมืองมูล

sort: votes


text:
What is this weird 1x2 with hooks on one side and two small bars on the other?
I was looking at my old bricks and found this weird piece. If anyone could help me find the element ID I would be ecstatic. The piece is a weird 1x2 with hooks on one side and two little small bars on the other.

Hi guest and welcome to Bricks.SE! The description alone could refer to many possible interpretations (plate or brick, shorter or longer sides, direction and size of the hooks and bars, etc.), but if you could please upload a photo of this part, that would be a lot clearer. Meanwhile do check if the studs have the LEGO inscription - the absence would mean it is a 3rd party piece, with probably no authentic LEGO equivalent.

It's difficult to identify a part for sure without a picture, but this sounds a lot like Technic Link with Two Studs (273):

It was used as chain links in various sets in the 70s:

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


text:
What are the changes in the RCX firmware version 0332?
There are three versions of the firmware for the RCX brick, of which I use 0328. I found out that version 0332 is about the datalog function. What are the more detailed changes between versions 0309, 0328 and 0332?

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


text:
I need help finding a Lego Star Wars set
I need help finding a Lego set I got for Christmas about 4-5 years ago. It was a gray spaceship with three engines. It wasn't small but not huge either. It wasn't a spaceship with multiple wings just two. The only other thing I remember is that the color inside of the engines was blue. It would be great if you knew one that looked like this or was similar to the above.

Hi tgamr and welcome to Bricks.SE! Are you looking for the set based on just the description because you don't have it at hand now to take a photo of it? If this is the case, then any information could be useful, like if there were any minifigures (how many, who, what colour, etc), what distinct parts were visible, what base and accent colours did it have, how big was the box, what did the instruction sheet look like, etc. Can you recall anything else?

thats the problem i was a child back the so i cant really remember anything but i know that it wasnt long but rataher like a triangle

I'd recommend browsing here, after setting the sorting to "Year released (desc)". There you'll definitely find the set you're looking for, but if I had to guess, you probably had 75315 Imperial Light Cruiser.

This checks the following boxes:

Was sold between 2021 and 2022
Is dominantly gray
Has three engines
Not small but not huge either
Has two "wings"
Has blue glow inside the engines

Although it is rather long, but still a bit triangular.
Let us know if you have found the one you're looking for, by writing an answer here and accepting it.
Edit
I've also found these, but they don't match all the listed criteria above - maybe you misremembered something?

75347 TIE Bomber
75348 Mandalorian Fang Fighter vs TIE Interceptor
75357 Ghost & Phantom II
75360 Yoda's Jedi Starfighter
75362 Ahsoka Tano's T-6 Jedi Shuttle
75363 The Mandalorian N-1 Starfighter Microfighter
75323 The Justifier
75325 The Mandalorian's N-1 Starfighter
75314 The Bad Batch Attack Shuttle
75186 The Arrowhead
75190 First Order Star Destroyer
75147 StarScavenger

After the comment saying you're not sure if it was Star Wars, you could still browse the Brickset database for the relevant years. You said 4-5 years ago, so maybe start with the sets released 3 years ago (in case there was a mistake in the estimation) and go until the ones from 7-9 years ago (sets can remain in stores after they are officially discontinued). If you are sure it was a LEGO set, you'll find it there, as Brickset lists all sets ever released. However, there are no such databases for 3rd party sets, so if it turns out yours was not genuine LEGO, the search will get a lot more difficult.
Anyways, try to remember more details: how big it was, maybe estimate the size based on other objects (your hand, a vase, other toys, etc.); did it come in a sealed box, if yes, how big was the box; perhaps ask other people who might have seen it what they recall; check if any photos were taken on that day; and so on. Keep in mind that while we are trying to help you, it is ultimately you who needs to put in the work to find what you're looking for.

thanks but it aint it

@tgamr Did you also check the first link?

yeah now i not even sure it from starwars

@tgamr Have you managed to find it?


text:
What LEGO set instructions do these 2 red and yellow brick bags come from?
The yellow and orange bag has 135149 on it, and the QR code comes up as 6351404.
The red and tan bricks bag say 2011 on it and also say 135149. There's also a smaller bag in the red and tan brick bag.

This question is similar to: How can I identify a set based on one or more original sealed bags?. If you believe it’s different, please [edit] the question, make it clear how it’s different and/or how the answers on that question are not helpful for your problem.

@zovits ah I see, should I edit my question or is there a way to link it to the question you linked?

There is certainly no need to link anything. The question in the comment only serves as a pointer for anyone trying to conduct their own identification process - be it you, another answerer, or a reader in the future.

Based on Yellow Plate, Modified 4 x 4 with 2 x 2 Open Center, Yellow Plate 4 x 8, and Reddish Brown Brick 2 x 4, these can only be from 10696-1 Medium Creative Brick Box.

Wow! Thank you!

@Jinx You are certainly welcome :)


text:
I need help to identify this similar lego freestyle
I'm dying trying to find where this lego came from. Maybe it's from 80s.
Some pieces have a tiny number inside. They are made of a resistant plastic.

The studs remind me of LINO bricks. The corners appear to be rounded somewhat though (possibly through use), and the underside looks more modern, so possibly a later evolution ? The specialty pieces (windows, doors, triangular bricks) don't look familiar.


text:
At step 92 for typewriter 21327 don’t see a way to connect the last two pieces to the spacebar
It looks like one of the legs of 6005331 (Technic, Axle and Pin Connector Hub with 2 Perpendicular Axles: ) should connect to the rubber piece 4198367 (Technic, Axle Connector Double - Flexible Rubber: ) but neither leg is long enough. Nothing else to attach 6005331 as far as I can tell. How does it attach?

By adding a picture it might be easier for someone to see if anything is wrong with your assembly.

Step 92 does not involve any rubber pieces:

The two technic 90° connectors go through the 2x6 plates and each attaches to the underside of a 2x2 round plate that you added on steps 85-87:

Note that the 2x2 plates do have an axle hole at its center (that should fit the 90° connector).


text:
How long would it take to build a 954 piece set?
How long will it take to build the Fortnite battle bus, which is a 954 piece LEGO set?

Different people build at different speeds. I guess a set of that size will take anyone at least a couple of hours, but anything from that and up is a valid guess.

We had a very similar question a number of years ago. While this one does specify a particular set, I think the likely answer is still too dependent on the person, or people, doing the assembly to be able to satisfactorily answer the question.

As others before noted, this can't be estimated easily - what I'd like to add is that beside the builder's experience, the style also affects build time. Some might like to rush the process, while others might take care in aligning all pieces perfectly or admiring the partial assemblies and the building techniques. If you can tell us the actual use case (i.e. why do you need the estimate - "is it going to be ready by Christmas", "can I build it during one episode of that show", "is the recipient going to get more value from it than from a book", etc), we might be able to help more.


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How to fix LEGO Mindstorms error code 5003?
I was using the NXT programming app and tried to download the file to the NXT, but it showed "Error code 5003". What is this error and what could I do to resolve it?

Does this happen for any project file or only a certain project?


text:
How I can connect the LEGO SPIKE Prime hub via Bluetooth in Visual Studio Code using the pybricksdev library?
I'm trying to send some data from the hub to the terminal for some debug. But I can't figure out how I can connect the hub via Bluetooth to my PC. I tried to look in the API documentation and maybe I found something but I'm not sure.

Pybricks is great, so is the support they provide, I think you'd be better of asking your question there: https://github.com/pybricks/support/

Hi tom and welcome to Bricks.SE! Can you show us what have you tried and how did it fail?

The easiest way to use pybricksdev is as a command line tool. I recommend using pipx to ensure that your are always using the latest version of pybricksdev.
Assuming you have already installed pipx and you have a terminal open in VS Code in the same directory as the script you want to run, run the following command:
pipx run pybricksdev run ble my_script.py

Where my_script.py is replaced with the actual name of the script you want to run.


text:
Communication between two Ev-3 bricks
How the communication between two Ev-3 bricks is done over Bluetooth? What is the nature of data that can be communicated?

Note that if you don't need wireless, the USB daisy-chain connection is a very convenient way to make several (up to 4 if I'm not mistaken) bricks work together - as you only need to create one program in which you can simply address all ports of all bricks.

It shouldn't be too much different from the NXT's Bluetooth capabilities, from what I perceive.

You can do it using EV3 Bluetooth blocks.
You can send integers, string or boolean using different "mailboxes" so the receiver just need to use the Block to read from a particular mailbox to get the data.
Maybe I write a post where I detail all this more because LEGO documentation isn't helpful at all.

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


text:
Turn a tank a specific number of degrees
I don't have a gyro sensor so that's not a possible solution (until I purchase one). I figured I'd just do the math on this one. What I'd really like to know are:

The circumference of the caterpillar track that comes in the Ev3 set. (I was hoping it would be etched into it, but I didn't see anything besides 1-01 in the rubber on the inner part of the belt).
The circumference of the rims that come in the Ev3 set.
The driving "gear" for this is the rim attached to the large motor(s), there are two followers that support the belt. Correct me if I'm wrong, but the only two things I should be factoring into the math are the rim driving the belt and the belt itself correct?

EDIT (answered parts):

If this is correct the length is 14cm.
If this is correct, the circumference is 3cm.

The math you're suggesting may work for going straight forward or backward where slipping is limited.  For a turn, it will not come close.  Even getting the center of rotation of the turning robot will be difficult.  The tracks will have to slip.  A tracked robot can not turn without those tracks slipping.  Differences in friction will alter the turn. More weight on the left or right, front or back of the robot will alter the turn.
Even abandoning the tracks for wheels is not guarantee that the math of how much the robot should turn will match reality.  This is not to say abandon the math, just a hint that it will only give an approximation.

I haven't noticed any slippage (yet, I've been testing on hard surfaces with lots of traction), but what I did notice is that the bearing value in beacon mode for the infrared sensor isn't a value I can base my calculations on. It's not degrees. I'm not sure what type of measurement it is.

As dfrevert said, tracks MUST slip to turn, it's impossible otherwise. The IR sensor returns an indication of the difference of illumination received by the two internal receivers, this is by no way an angle. Same of thing when used as a distance sensor, it gives an indication based on strength of IR echoed to the sensor, so it is not linear and repends on reflectivity of target.

A 360 degree turn takes: (width of robot/circumference of wheel) turns, neglecting track thickness, assuming the tracks are at sides if the robot.
The length of track doesn't matter. Your robots non-slipping part of the track is traversing a circle of diameter=width of robot. The other parts of the track are sliding across the surface.  A longer robot / track only affects the efficiency of turning not the rate.
If the surface is rough, there may be jumping and movement of the center of rotation. Calculations are good but don't be afraid to calibrate to the surface after testing.
Not sure why you are using IR sensors for turning. the ev3 motors have encoders and can be told to turn fractional rotations or by degrees.

One possible reason for using something other than the motor encoder is to account for the slippage - if you don't know how much your tracks are slipping, telling the motor to turn 20 degrees isn't going to result in a 20 degree output.

agreed, but the constraint on the question was encoders only. and since tank drive is a inherently a skid drive, accounting for the slippage correctly is not really possible without something like a gyro or external reference.  In any case in practice, slippage of the pivot points on smooth regular surfaces is not an issue unless pushing something.


text:
Opera house 10234 book 2 instruction 20 left hand side and then 22 has got me stumped. Can't figure out how these pieces fit. Please help
Opera house 10234 book 2 instruction 20 left hand side and then instruction 22 has got me stumped. I am not sure whether there is a space between the "high 2 and the blue 4. Please help

There is indeed 1 stud between both parts.
The gray 2x1 is on the yellow 1x1 and 1 stud of the brown 6x1, than there is 1 free stud on the brown piece. The blue brick is on the remaining 4 studs of the 6x1


text:
Will they ever make LEGO The Amazing Spider-man 2 sets?
I realized that they released an exclusive minifigure of The Amazing Spider-Man 2 in the San Diego Comic Con but I am still wondering if they will ever make LEGO set(s) based on the movie.

It depends on licensing as well. Note that they have made sets for Ultimate Spiderman. The X-Men designs all follow their comic counterparts. Loki, Thor etc follow their Movie style counterparts.
This suggests that they have the license for the comic and animated styles, but Fox and Sony retain the rights for the movie looks of the characters.

This is correct. Lego does not have a licensing agreement with Sony who owns the movie rights to Spider-Man. They currently Spider-Man sets based only on Marvel IP. (Note that the "Amazing Spider-Man 2" designation for the Comic-Con exclusive from 2013 does not actually name that film anywhere on the package.)

That depends. First of all, the movie needs to leave theaters. Seeing how LEGO has not made an Amazing Spider Man 1 set, it is fairly un-likely they will do sets for the sequel.

The movie doesn't need to leave theatres before Lego makes sets for it. Lego had a license for the first two Spider-Man movies in the early 2000s and their sets were released before the movie, as are most movie tie-in sets.

Actually yes the will Because in 2014 October Sony has SIGNED lego tasm to Lego They made a electro Polybag that was given out But thats all i know but yeah They will make some because they have Rights to

This is just speculation.  Do you have any sources to back this up?  Also, please try cleaning up your grammar and spelling.


text:
How can I make a precise one-way clutch using Technic elements?
I need a mechanism so that if a (NXT) motor rotates forward, it moves one gear, but the other stays still, but if it rotates backwards, the first gear does not move, but the second one does.
I found an example solution for one half of the problem here (I would need 2 of these), but that seems like it would take part of a rotation to pick up, and I need mine to be really precise.
I am building this for the Z-Axis/Extruder of the NXTStrap.

Would this solve your problem? Depending on the direction of the input, only one axle will turn.

Does this solve @Ari Porad 's problem? The best resolution you could get with this device is 1/4 of a turn.

^ Why would you say that? It's free to rotate as much as it wants, because the four-lobed "Gears" will simply slip underneath the angled stoppers, in one direction.

@RallyToMe, technically MindS1 is right, it could take as much as a quarter turn until the knob wheel gets locked. This can however be reduced by using ordinary gears, the more teeth the smaller the error at the price of increased size.


text:
LEGO mindstorm - which product to use to make projects mentioned below
I'm planning to buy a Lego Mindstorms kit for the following projects. I haven't really used Lego before - my friend asked me to consult him about projects (I use microcontrollers and build robots from material I find in my garage).

Two track tank with a distance sensor to create a map of a room. A gyroscope sensor to measure the angle of slope would also be very useful. It would use fuzzy-logic, A* algorithm and OpenCV if I decide to put a web camera on top of the tank.
Inverted pendulum (PID controller). It needs an encoder and a rather high speed motor which can change it's direction of rotation.
Some crawler (like a snake or spider) - models with holonomic constraints.

Now I'm considering the EV3 basic educational kit and I think it doesn't fit my needs. I also can't understand some things about software - if I buy a kit for home use, I suppose I shouldn't buy any software.
Questions

Which kit would be the best fit? Maybe two kits or even three?
Is the servo limited in rotation or can it be used as a simple electric motor? If no, then which motor can be?
Can I program the models using free software (downloaded from a website)? C or Java is preferable. NXC is nice too (it looks like C, but I haven't used it before).
How to remote control the robots? Should I buy additional Wi-Fi adapters?

A basic EV3 seems to be enough for most of the basic projects, but you might find yourself in need of a handful of extra parts (gears, beams, etc). The basic kit does not include a gyroscope, but you can buy an extra one separately. The same stands for the ultrasonic distance sensor.
The alternative is the educational set which already includes the ultrasonic sensor.
All EV3 sets come with the official software, but for any serious project you should indeed look for a more capable software. For Java there is LeJOS, for C there is NXC. Both are free and open source.
The motors sold in EV3 kits are capable of continuous rotation, but also have position encoders in them, making them capable of moving with 1° precision. For more precision you can always use gearing or other mechanics to reduce movement.
Remote controlling is possible with Bluetooth (built in) or with WiFi (via an external USB dongle).

Thank you very much. I've checked there is a gyro sensor in ev3 education core set.

If my answer was useful to you, please consider marking it as accepted. Thank you!

@IvanIvanov Just to add, LeJOS provides a remote control utility for controlling motors and reading sensors wirelessly. You can link to an EV3 over bluetooth or Wifi, but you will need to buy a wifi adapter for EV3. NXC is for the NXT brick, not the EV3 - if you're looking to code C, take a look at EV3RT.


text:
Looking for information on a Lego manual I had as a kid
I had a lot of Lego when I was younger (in the late 80s/90s). In a flash of nostalgia I recently remembered having a great instructions/ideas book that I loved to read through - I can't remember the number, or even if it was an official instruction manual, all I can remember is that it contained information on a 'line plotter', which used a roll of paper and a few pens to draw lines, which at the time I thought was amazing - I may have even built it.
I've been able to find out some information - it appears that the plotter was built by Larry Page (yes, of Google fame!), and I have also managed to find this picture from the book...

Does anybody else have any information on this book? A PDF would be excellent, but any information would be of interest to me.
Many thanks,

The book you're looking for is the "Expert Builder Idea Book (8888)". The complete book is available on Peeron.

You're welcome. I absolutely loved this book, and was always fascinated by the plotter. I don't think that it is any coincidence that I enjoy a career as a programmer, and would site this model as one of the inspirations behind my vocation. I'm delighted to be reminded of it all.

Sadly, I'm not certain that the model in the book was by Larry Page. Wikipedia (http://en.wikipedia.org/wiki/Larry_Page) says that Page designed his LEGO plotter whilst at University. The Idea Book was published in 1980 when Page would have been about 7 years old. I don't doubt that a prodigious 7-year-old might come up with a clever LEGO design, but I'm not sure that he would be at University by that age.

I agree. I assume the post in which I read about it probably had the wrong picture (which is the one I've included here), nonetheless, the link you provided was the one I happened to be looking for, thanks again.


text:
Where can I learn how to program an NXT using C#?
I've been toying around with my NXT 2.0 set for a few years now and I would like to learn how to program it using C# language. I have no experience in coding and I am definitely not a computer geek. Are there any tutorials that can give me a headstart in this thing?

If you have no experience in coding, why are you set on programming the NXT in C#? There are other options, such as using LeJOS NXJ which helps you program the NXT using Java, arguably the language C# was largely modeled after .....

You could start here for example: LEGO MINDSTORMS NXT Tutorials Overview
For a generic C# introduction see here: C# Tutorials or The complete C# Tutorial or C# Tutorial or just do a Google search for "C# tutorial".

Thanks a lot for the suggestion, i really appreciate that .

You are welcome! If any answer proved useful to you, you can upvote it with the upward pointing arrow on the left side. Or if you think an answer is the correct one for your problem, you can also mark it with the check mark as accepted, signaling the future readers which solution works.


text:
Brick Compendium: BIONICLE LEGO
Is there a comprehensive compendium of the old Bionicle pieces?
For example, what is the part name for:

Tahu Mata's flame sword?
Lewa Nuva's twin blades?
The Zamor Sphere's holder, as used by the Toa Ignika?
The Midak Skyblaster?
The zipcord whirly-peg thing for the spinners?

You will find most LEGO pieces, including those that are specific to the Bionicle theme on Peeron.
For example here are your particular mentions:

Technic Bionicle Weapon Flame Sword 2 x 12
Technic Bionicle Weapon Blade 12L
Technic Bionicle Toa Inika Zamor Sphere Magazine
Technic Bionicle Weapon Midak Skyblaster with Black Housing
Technic Bionicle Rhotuka Spinner Ripcord 12L with Hand Grip


text:
How do I get missing parts for a Cobi set?
I got the 1305 set from Cobi. I am missing 3 or more pieces. I can't complete the model without these pieces:

2 normal black 1 cm high, 6 studs long, rectangular (not round edge)
1 black rectangular flat 3 studs long, 2 studs wide.

How do I order only these parts?

You can order individual parts using Blocks by Piece.
I think the two parts you describe are 2x6 czarny and 2x3 1/3.


text:
Adapters for Lego Duplo and Mega Bloks
Similar to this question I am interested in combining Duplo Lego with Mega Bloks.
I want to have full compatibility, i.e. being able to put Duplo on top of Mega Bloks, which requires some type of adapter.
I am looking for BUYABLE adapter pieces (not self-made via 3dprinter or such).
Does anyone know a source?

I found that Lego has a (discontinued) system called "Lego Primo" with similar round studs. It does have adapter blocks for Duplo (marked with red rectangle):

Can anyone confirm that these do / do not fit the Mega Bloks studs?
Although they are discontinued, they can still be bought used. So if they fit it would be an option for me.

There is an unconventional type of adapter being sold on Ebay (seems to be just a single offer, used):

Has anyone ever seen these somehwere else? Maybe even in real life? They do not look 3d-printed, they look injection molded (like Lego and Mega Bloks). So there might be someone producing them (or having produced them) commercially...

I've linked to the eBay item your picture comes from, in order to let others see the whole listing with all images. Note though that the listing explicitly mentions how "They are extremely hard to find." I can easily imagine someone having set up an injection molding line for these parts, and only producing a handful of them before getting hit by C&D letters from both TLG and Mattel - thus limiting the availability of these parts severely.

I have several of the second (white) adapter you show in the photo, from my original 1990s Mega Bloks sets. I have the original Ritvik Mega Bloks (the only size now sold) as well as a Ritvik Mega Bloks set that is almost identical to Duplo blocks (sold in the early 90s, mine are marked 1992), with the white adapters made by Ritvik.

Primo and Mega Bloks are not compatible.
The Primo piece loosely fits on a Mega Blok piece:

But the Mega Blok piece does not fit on the Primo stud.

As for the adapters in your second photo, I have seen them many times in used toy collections I've bought; unfortunately, I don't think I've ever seen them new in the package to give you a specific reference on how to buy them. But I've always assumed they were an actual Mega Brands product.
I have a 2x2 (or 1x1) and 2x4 (or 1x2) in front of me. The smaller says 430 and © 1988. The larger says 439 and PAT PEND and © 1988 and (tellingly) Ritvik. (Ritvik was the maker of Mega Bloks.)


text:
Where can I get replacement battery connectors for old Lego Duplo Train?
I have the same Duplo Train that Pieterjan posted a picture and video of in September ('Old Lego duplo train not working on batteries'). In my case, it is clear that the battery connectors are corroded due to leaked batteries, and some have snapped as I removed them to clean them. Any idea where I might be able to buy replacements?

Considering that the contacts seem to be made specifically for this model of Duplo Train, I think an exact fitting off-the-shelf version likely doesn't exist. You could buy sheet metal of the same material and thickness, then try to cut and bend it to the right shape - or buy another (possibly otherwise broken) Duplo Train of the same type (or in red) to scavenge the connectors in used but official condition.


text:
How to find out where a previously lost brick fits?
Rebrickable manages a list of lost parts. If I later find one of these, I have to go through the PDF of instructions to put it back where it belongs, which can be tedious. Does someone know if there is a database of searchable instructions to directly get to the right page? Or better yet: instructions for commercial sets in a format similar to the one used by Bricklink Stud.io?


text:
Looking for a PC controlled motor that allows for very small and precise movements
The image below is a LEGO specimen stage designed for a stereo microscope.  I am looking for a recommendation for a PC controlled motors that allows for very small and precise movements.
I want use the motors attached to my specimen stage to make a very small height adjustment and then I want to send a command and capture an image from the camera-mounted to the microscope.
Here is the workflow I hope to achieve by motorizing the specimen stage:

On KeyPress (from with C# Windows application)

Activate stepper motor, adjust height (z-axis) by 100-200 µm
(maybe 2-4 steps in a 200 step per revolution motor)
Wait 200 ms (allow time for vibrations from movement to stop)
Activate Camera - capture an image
Save image (auto-named) to my folder.

Possibly using SDK like:
https://github.com/pololu/pololu-usb-sdk
Any Suggestions?

Working solution:
The picture with the stepper motor on the input:

Full View:

What is "very small" ? How precise ? Did you account for the inherent slack in the system from the gearing (turning the first gear in a series of connected gears needs some movement before the last gear in the series starts moving) ? Does it need to be immediately reactive (is it allowed for the movement to take a while to occur and/or complete) ?

Worm gears are usually slow, but quite accurate.

My first thought would be to hook a servo motor to an Arduino board, and use the Arduino's serial-over-usb capabilities to receive commands from a computer. However, the slack inherent in technic gears is gonna be an order of magnitude larger than the precision of any half-decent servo. If the goal is to raise/lower the platform repeatidly, two chained worm gears might be a better option.

The slack in the technic gears are a problem.  I am currently minimizing this affect by always adjusting upward because weight of the stage  + slack of the gears does cause the platform to drop when adjusting the height downward

That's why newer designed gears to fix this issue.

LEGO gears were never designed to be precise so there always going to be some slack. But as I mentioned, you can achieve reasonable accuracy with worm gears. This would work if you want to make fine adjustment in single direction - while doing so you will have all gearing connected snugly, thus reducing any slack. But if you moved something to far and need to move it back a little then all gearing will come out of accurate setup until you reduce slack in opposite direction.

Ok I need to my improvements

Should I use a stepper motor or servo motor or are these the same. Can someone help me understand the differences?  thx

The stepper motor is an open loop motor with gear like rotor that rotates otayes in steps (not continuously going) and servo used a position sensor that rotates by an gearbox until exactly at X degrees

I don't have any motors with positioning systems.

Or I don't have a 3D printer to make adapters

You could always build your own stepper motor from a regular lego motor, eg. one of sariel's designs.

this is too much adjusting the x y movement, but you can use LEGO motors with a rotation sensor that you can use as a servo.

i don't have a knob wheel in my parts

i don't have enough parts for my improvements like fewer gears or anything

delayed, pls wait for an answer to my fans..

Lego gear teeth have a pitch of 3.2mm (I did not measure. Maybe trust the www?)
You want .2mm or 200 µm.
3.2mm / .2mm = 16
Worm gears provide this with 360 degrees/16 = 13.5 degrees
I'd suggest 4 motors, each driving one set of worm gears on the four corners of the platform being raised/lowered. Of course, you may not have four motors. Adding a gear train will lower the accuracy. There are 40 tooth gears, that when combined with the 8 tooth gears could work. The worm gears are tricky, they need to be braced; their symmetry is not obvious.
Interesting problem.


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A query about the balance of the 42130 - BMW M 1000 RR model
I have reached assembly step 632. The bike has a tendency to lean forward with most of the weight at the front, and is only just staying on the display stand. Has anyone else experienced this issue?

Edit:
I have now completed the build and the bike is definitely front loaded and sits with its wheel on the desk and the rear end raised. Again, has anyone else found this issue ?
Here is a picture to illustrate the problem.
Here is another picture to illustrate the problem.

Your front and rear wheel/tires are likely swapped. I didn't realize until I finished the entire set and had the same problem as you. Swapping the front and rear tires solved my issue.

This is the correct answer, from the picture, the thicker (and hence heavier) wheel is in front while it should be in the back

@MichaelVerschaeve I think you are right. It looks to me that the fatter wheel is on the front as well. As the front is slightly heavier anyway the swapped wheels add enough weight to tip the model.

I do not have this issue. My model balances fine on that stand.

There are some elements behind the front wheel I leave out as they keep falling off (only attached on the studs of a couple of half pins) but that should hardly make a difference...
Here's a picture of the bottom of the bike, perhaps you've done something in error there ?

I just finished my own build of this one. It is front-heavy, but not enough to tip over. It sits relatively stable on the stand. Those radiator pieces are indeed  irritating. They are only barely attached and kept falling of while attaching the various pieces of fairing around the engine-block. I wonder if replacing the blue half-pins with the creme-colored ones will help. The creme ones have slightly longer studs and maybe a little more grip.


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How to change colour of the bluetooth/charging RGB LED in the hub?
I have the Mindstorms set 51515 - Robot Inventor. I want to display the progress of a robot's work using the LEDs.
How can I change the colour of the RGB LED that the hub uses to indicate the Bluetooth/charging status?

Short answer: You can't.
Longer answer: It should be possible to do with custom firmware, but it's (a) not worth it, (b) difficult from a technical standpoint, and (c) a bad idea.
Disclaimer: besides being an AFOL, I have some experience in the microelectronics industry.
What's this "firmware" thing, anyway?
When you load a program into a spike/mindstorms/ev3/etc hub, the hub is not running just your program. It's running a lot of stuff under the hood.
In fact, your program (i.e. "the user program") does not communicate with the hardware (motors/sensors) directly. It communicates to the operating system of the hub. That's commonly called "firmware" since it lays somewhere in between "hardware" and "software". It's assumed to be immutable and reliable as hardware, but with some effort can be changed/updated as software.
The firmware handles the tricky bits of computing that you don't want to care about - such as the Pulse-Width Modulation for the LED colours, the Real-Time Clock to run commands for specific amounts of time, or the USB and BLE network stacks to communicate with desktop/laptop computers.
Note that your user programs do not have full control over the hardware, or over all the features of the OS. For example: any device with a USB stack and a button can be (in theory) converted into a USB mouse (technically a "USB HID")
Why is it not worth it?
Because it takes a lot of time; and given the amount of person-hours that it would take to develop custom firmware (such a pybricks, the only non-lego™ firmware I'm aware of), you'd be way better off getting an Arduino and/or a Raspberry Pi. That way you can learn to take full(er) control of your hardware.
Or, if you just need extra lights, get set 88005-1.
I'm assuming you are reading this from the point of view of a person just learning computing/robotics. If you already have experience in computing, tweaking pybricks or even Zephyr wouldn't be out of the question.
Why is it so difficult?
I've skimmed the source code for the pybricks firmware. As far as I can see, the code paths for the user-programmable RGB LED and the battery LED are completely different. The former is treated as a peripheral, but the later is treated as process events passed to the underlying kontiki OS.
So in order to make the battery LED user-programmable, first you would need to disable it at a lower level. Which means losing the default behaviour for that LED.
Why is this a bad idea?
When developing low-level firmware, the ways that the computer (the hub) can display information are very limited. I'm talking no bluetooth, no USB, no UART: a status LED is in most cases the only tool available. Losing that tool  is plain dangerous.
From a support point of view, letting a user fake the behaviour of that tool means that you couldn't trust problem reports. If a LED is stuck on a colour, how can you be sure that it's a problem with the OS, or maybe is it a problem with the user's program?

As far as I know, this is not possible with the default firmware and APIs currently. The primary hub LED is exposed as hub.led, but I don't believe that the other LED is accessible from user code.
It may be possible to access it in some undocumented way or via custom firmware, but I'm not familiar with any way to do this.


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Fit motor to old tractor

I'd like to motorise this tractor I built from an old Lego book.
I've 4.5 volt motors. The model is 6 studs wide, the motor is only 4, and since the tractor uses big wheels it would be too fast. Is there a possible gearing from the motor to the wheels, which is only 1 studs thick that I could use?
I've also got a 9 volt motor, so would it be possible to use bevelled gear wheels to go through 90° to the wheels?

You'll have to be more specific. Which tractor? From which book? Which motor, exactly? A couple of photographs would also help.

Sealed motor, Fordson? Don't know what book as missing 1st page.

Hi Andrew! I took the liberty to copyedit your question for better readability; please give it a read and fix anything I might have misinterpreted, as your intention was not always 100% clear.


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Cat D11 LEGO set won't start the calibration process
As soon as I start the calibration process in the app, the gearbox jams. It doesn’t do anything, just clicks and clicks (stripping the gears). Any ideas what the cause might be?

Possible duplicate of https://bricks.stackexchange.com/questions/16634/caterpilar-d11-set-42131-control-app-doesnt-seem-to-work. Please note that that question doesn't have an accepted answer but the actual answer is in the comments.

Most likely a mistake in step 87.
The two most common malfunctions are

clicking gears and no motion for the shovel, ladder and plow but tracks are working: redo step 87 meticulously.

Wrong engine activation in the gear box often happens. (often ladder moves instead of shovel) and calibration fails. This is a bug, the engine mistook the placement of the gears, and calibration doesn't catch it in the beginning. To fix, Cancel calibration, press the app button to lower the shovel and remember to wait for the gear to be changed, then retry calibration. If that fails again, try the shovel tilt and redo. If that also fails, then lower the plow and redo. It cannot be fixed by the ladder unless the gearbox was built wrong, (in that case you need to do 87-120 again).


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How do I disassemble Powered Up Motor XL?
My question is, how do you take the XL motor apart?
I tried with my knife and hands, but unfortunately, it is still whole in one piece (tabs).
I got the XL motor from the set 42099 and I would to make the set again if it wasn't stuck.
I want to open the motor so I can see what's wrong with it; I think it is actually a broken motor.

What does the motor do or not do that makes you think that it is broken?

Also see https://bricks.stackexchange.com/q/15031/3498


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Gearbox doesn’t move when it’s in neutral - Is that normal?
I’m not sure if the gearbox is supposed to move when it’s in neutral but the gearbox only moves when it’s in drive or rear. If I made an error can someone please tell me if there is a way to fix it?

I suppose you mean the cogs in the gearbox should move, right? I mean, I'd be concerned if the gearbox moved, neutral or not ;-).

Do you just mean the output shaft doesn't turn, or do you mean the input shaft locks up?

The point of the neutral position in a gearbox is that it disconnects the engine from the drivetrain. Therefore no movement is expected at the wheels when the engine turns and vica versa. If the pistons move (their crankshaft turns) when the wheels are turned in drive and do it backwards when in reverse your build is okay.


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42114 (6x6 Volvo Articulated Hauler) doesn’t operate bucket and also doesn’t drive
My 42114: 6x6 Volvo Articulated Hauler drives in first gear for a moment, then stops completely; same thing with 2nd and 3rd gear. It doesn’t operate the bucket either. I suspect I forgot to add a pin to the L motor and the orange gear shifter - how can I fix this the easiest way possible? I’ve calibrated about a hundred times already: sometimes it works for a few seconds then stops completely.

Exactly how does it stop ? What do you observe when that happens ? Is the motor still running (do you hear it) ? Do you hear and/or see any skipping gears or other horrible noises ? Can you see at what point the movement from the motor stops being transferred (is it a gear that no longer connects, or a shifter that became misaligned, or ...) ? If you found where the issue occurs exactly, can you take a picture, and include it in your question (ideally with an arrow pointing to the issue) ? Etc.

It might be the case that the batteries can only supply the required power to move such a heavy model in the first few seconds, then their voltage drops below the required limit for the motors to keep on running. Can you try or have you tried using new, non-rechargeable* batteries?
Adding a missing pin might be trivial in one case and might require a complete teardown and rebuild in the other case. Without knowing which pin did you forget (if any) it is impossible to tell which one applies to your situation.
*: the non-rechargeable ones have 1.5V as nominal voltage, whereas the rechargeable ones commonly top out at 1.2V, which then drops further as they get empty.


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42131 Bulldozer Testing
Got to the testing page and everything is working correctly except the left track is going in the opposite direction to the app animation.
Should I start again?

Thanks - I saw that and have also now rebuilt and the same parts are still moving opposite to the animation so I will continue to build it as they have done - hoping for the best!!! Otherwise, it’s a massive tear down and rebuild!


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RCX only accepts short programs
I'm new here. I used to use the old Mindstorms to teach robotics at a school back in early 2000s and I thought my grandson would like it, so I have bought an old second hand system. The RCX brick works and the tower is connected to the USB-serial port adapter. It says the RCX is working fine and will download 4 or 5 prog blocks. If I try more it tries but won’t download. Do you have any ideas?

I've encountered this issue before, but I'm not sure if I remember how I solved it. What OS are you using (and what usb-to-serial converter, if you have that info as well?)
In the meantime try the suggestions here: https://bricks.stackexchange.com/questions/10160/serial-tower-rcx-1-0-works-with-nqc-but-flakey-with-ris-2-0

Thanks will look up info.

Thanks it is running on XP sp3. I have looked at your link but so far no progress. Additionally when I exit the software something remains as it will not reload saying only one copy of mindstorms can run.

Now failing to download built in progs!

Couple more questions for you:  1) Is this Windows XP running in a virtual machine?  2) Do you have access to a USB version of the IR tower?  3) It's possible the drivers for the USB to Serial converter are outdated, but the solution depends on its internal chipset. Mine uses the Prolific PL2303 chip, which has WinXP drivers here.

Also try installing BricxCC which is a popular 3rd-party tool for interacting with the RCX. It supports the USB and Serial towers, and supposedly works more reliably than the default Lego software. See if you can download the firmware, control motors, download programs using this tool instead. Could help diagnose the issue.

Hi, the machine is an Xp not virtual. Hope to get another RCX on Friday to try the tower is serial running on usb converter I will try another converter. I have downloaded the bricxx but have not tried it yet as it is too much for the 8 yr old. Will give it a go.

Got an older Xp system and it all works fine on that so defiantly looks like it is the usb serial converter that is giving the problem  so I will sort out another converter and see if that fixes it.

Glad to hear it! My understanding is this is a fairly common issue, so I've summarized our discussion in the answers section so future people can benefit.

The saga continues. I have acquired a usb tower. I thought this would solve the problem. I have installed it with the L tower software but the mindstorms still can’t find it. Any ideas?

Summarizing our discussion from the comments:
System is running Windows XP SP3 (not a VM) with an (unknown) USB to Serial converter connected to the Serial IR Tower.
Problem is that most interactions with the RCX are unsuccessful; Communication begins, but is typically interrupted partway through downloading programs to the brick.

OP attempted suggestions from this post, with no luck.
Tried a different RCX with no luck.
Tried a different WinXP system with a built-in serial port and downloads were successful. Indicates the problem is with the USB to Serial converter.

Conclusion: Not all USB to Serial converters are compatible with the Mindstorms Serial Tower. It is known that USB to Serial converters based on the PL2303 chipset work reliably, but this information is not always readily available. PL2303 has driver support for Windows 98 thru Windows 10, currently available for download here.


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Best way to get Cara Dune minifig
With so many Mandalorian sets being retired this year and the controversy around the actress, I don't want to miss out on the Cara Dune minifig.
What sets is this minifig available in and which is the best value for money?

When I answered the question, it asked about "what ways" to get the minifig. Now it has been edited to read "What sets is this minifig.. in" which is NOT the same.

@RSchulz I did the edit thinking it wouldn't change the meaning of the question significantly. I still consider your answer relevant, though you're of course free to restore the original wording if you feel that version would fit your answer better.

Bricklink has lots of them for sale - depending on how close to you one of the sellers is (to cut down on shipping cost, or even to pick up in person if that's allowed) you might not be able to beat that price anywhere.
If you need 700 of them, there's one seller that claims to have that, and more.

If you want to buy Cara Dune in a set you can buy the AT-ST Raider 75254 from 2019. The only other set she is available in is 75315 Imperial Light Cruiser, which is significantly more expensive.

Welcome to Bricks.SE! Thanks for your willingness to share you knowledge with our community. I updated your answer to include a link to the set you mentioned and expanded it to include the only other set I'm aware of with this minifig.

Just buy the AT-ST with Cara Dune (75254) in it. Alternatively you could look on Bricklink (as RSchulz sugggested) or eBay.com.

Welcome to Bricks.SE! Thanks for sharing. It's worth noting that this set is no longer sold on LEGO.com in most markets and will likely be disappearing from retailers as their stock is sold making it hard to find and/or expensive in some locations.


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What’s this brick called? Two studs long and has clips on one side
It’s two studs long and has two clips with horizontal openings on one side.

BrickLink calls it Plate, Modified 1 x 2 with 2 U Clips (Horizontal Grip), but it might be the newer Plate, Modified 1 x 2 with 2 Open O Clips (Horizontal Grip) that @Alex politely pointed out. I always have a hard time telling them apart in real life, let alone from photos.

thank you very much :)

Could also be a newer version.

Oops, yes, I should have included the information BrickLink almost threw at me. Thanks!

The 60470b page has an image that shows the 60470 and 60470b side by side in profile so you can see the difference between the clips.

I have seen the clips in person, and been able to tell the difference, probably. Even that image doesn't really do much for my understanding, alas. (I also don't know at what point I am supposed to move the comments to chat.)

The primary difference is squared or rounded ends on the clips, for all the blurry image, this looks like the new one to me. Open O rather than U

@Separatrix I agree. The angle of the photo is not great, but it does seem like the tips of the clips detach from the surface the piece is lying on. If it were the U, they would lie flat.


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Help identifying non Lego blocks
I'm in the UK. I've been given a box of old Lego bricks from when I was a child (80s). These were mixed in. I seem to recall they made a house perhaps? They are larger than Lego, smaller than Duplo (Lego and Duplo block included for size comparison). The 'studs' on top are hollow. They had clip-on wheels in the set and window-like push-in inserts. I cant find any names or identifying  marks. Has anyone got any ideas what they are?

Judging by this website, they appear to not be "American Plastic Bricks" by Elgo: https://www.madeinchicagomuseum.com/single-post/halsam-products-co/


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Who can make a custom made LEGO 777 airplane?
I work in an advertisement agency and our client wants to make a LEGO custom made airplane branded with their branding to be given to their offices. Is there anyone who can make the instructions and what parts should we order and we will build them ourselves?

We don't do communication outside this site, so I've removed your email and the suggestion to email you.

About your question: I don't think anyone will give you instructions+part list without getting some form of payment and you haven't mentioned anything about that, but what are you willing to pay? (I can't do it, so I'm not asking because I'm interested).
You haven't said anything about the scale of the model they want. For the rest of the answer I'm going to assume a scale that means the model will contain some hundred parts.
To address the final part of your question: Depending on what parts are used in the design you want to go with (and the depth of your pockets - some parts are very expensive) there should be no problems in you ordering the parts and building a number of copies - note that it might take quite a bit of time to actually do that, depending on:

the size of the model
the skills of the people doing the building
the building techniques used

If you can find a local builder who wants to take on the task, it might quickly become cheaper to ask them to build a number of copies.
You haven't said where you are, but if there are any LCP's (LEGO certified professionals) near you (or any of the client's offices), this sounds like a job they would like.

Henrik is spot-on with his suggestions for more details and things to think about here.
But I have a particular suggestions for the who part of your question: talk to BigPlanes from youtube that recently started their 777 project.  I don't have any contact information for this youtube user, but you could start by making a comment on one of their posts and see how it goes.
You could also try someone that builds Boeing planes on Rebrickable, but I didn't see anybody trying to do a 777 up there yet.  One advantage of Rebrickable is that most of the participants are used to creating instructions for their sets.


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Delete projects from Mindstorms EV3 Brick
I am using Lego Mindstorms with https://makecode.mindstorms.com/ and once the projects are downloaded to the brick, I cannot delete them anymore.


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Ev3 classroom 1.5.2.0 not working
When I try to create a new project or open an old project, the program does not work.
We have 10 computers (desktops) with different versions of Windows 10

Stuck on this.

Hi Martin and welcome to Bricks.SE! Can you please share more details concering your issue? Does "stuck on this" mean you can't advance from the depicted state? Can you see any error messages or can you use other functions?

We have the same issue. Similar set up.


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Where should the 76139 Batmobile roof pins land?
Lego Batmobile 76139.
Could someone please advise whether the pins installed in step 445 should rest on top of or just in front of the stanchions installed in step 417 ?

Caveat: I don't have this set, so am just looking at the instructions.
It looks like the pins should rest alongside the Axle 1L with Pin 3L you pushed into place on step 294:

You can possibly see that a bit clearer on step 447:

They should therefore rest just in front of the two SNOT assembles you added in step 417.
That's also borne out if you count 12 studs from where the Axle and Pin connector sits when lowered - the end of the 12L axle comes to the just behind the pin mentioned in step 294.

Thank you so much - I thought I was right but just wanted confirmation before moving on :)


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How to create parts inventory for Rebrickable?
I have literally thousands of pieces of LEGO from our childhood. I have sorted them and now want to scan the pieces using an app like Brickit and then import them into Rebrickable.
Is this possible? How do you save the pieces in Brickit? Is there a better way?

If you don't have reduced your pieces to some known sets, then I'm afraid, you  have a lot of manual labour to do in order to create your initial list of elements you own. One tool that could somewhat help with that is BrickStock.
This guide on Rebrickable explains how you can import your elements into inventory. If the app you use could create TXT/CSV file of all scanned elements (it would be best if identify and store part ID, rather than names), the following option available on Rebrickable could be used:

Choose a file or external site to import from. You can manually create
your own parts file if you like, the easiest is probably a CSV
formatted file with appropriate headings. Rebrickable will
automatically detect the columns as long as you use the correct
headings (in any order): Part, Color, Quantity. For example:
Part,Color,Quantity
3001,15,100
92947,0,100

Color IDs can be found on Rebrickable as well.

Thanks Alex!!! That’s probably a lifetimes work


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Please identify this green pin
I bought the 42153 set yesterday and I got this green rare pin in bag 1.

How can this Technic pin be used?

I assume you mean this pin:
https://www.bricklink.com/v2/catalog/catalogitem.page?P=65826

Which was first introduced in the Spike Essential set, but is currently also present in a couple of other sets, e.g. the Technic set NASCAR Next Gen Chevrolet Camaro 42153, as you mentioned but also the Volkswagen T2 Camper Van (VW Bus) 10279
Its purpose is to connect system elements with Technic elements, it serves a very similar purpose as the half pin
https://www.bricklink.com/v2/catalog/catalogitem.page?P=4274

with the main difference being that the stud on the pin is inverted. Rather than enabling to connect a system elements with the studs away from the Technic element, with the green pin, you connect the system element with the studs toward the element.

I have 2 plus a spare one. (42153)


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Which Harry Potter set is this table from?

I have been gifted a lot of 10 + years old Lego. I don't have any instructions books. Any idea what sets could these be so I could try to find them online please?

I can identify the following parts:

2 of "Cheese slope" in reddish brown
2 of 1x1 round plate in trans-neon-orange
2 of 2x8 plate in dark tan

A search based on that criteria yields only one result: set 4182 "The Cannibal Escape" from the Pirates of the Caribbean franchise.
One of the sub-assemblies in the set resembles the one in your photograph very closely:

Alas, you don't have a Harry Potter table. You have a cannibal bonfire.

Ah, right, trans-neon-orange... /facepalm. Nice find!

Thank you @IvanSanchez definitely the Cannibal Escape as I have found other elements in my Lego box!. You are such a great help!

Update: this answer is based on a false premise and is therefore invalid. See IvanSanchez's answer instead.

The photo clearly shows 2 of Reddish Brown Plate, Modified 1 x 2 with 1 Stud with Groove (Jumper) and Trans-Orange Plate, Round 1 x 1, and 4 each of Reddish Brown Plate 1 x 4 and Reddish Brown Slope 30 1 x 1 x 2/3. There were only two sets in which all of these have appeared: 79003: An Unexpected Gathering and 10236: Ewok Village - UCS, but neither of these have a 2x8 plate in any colours besides black, green or reddish brown - none of which corresponds to the ones your photo depicts.
So this sub-assembly must not have come from an official set, or at least some parts have been added to it.

Edit based on Henrik's comment:
Updating the search to include piece 15573 (Modified 1 x 2 with 1 Stud with Groove and Bottom Stud Holder (Jumper)) results in matches for 71040 Disney Castle (contains only dark bluish gray and white 2x8 plates), 70677 Land Bounty (just reddish brown 2x8), 40346 Legoland Park (green and white), 910003 Mountain Windmill (reddish brown) and 75220 Sandcrawler (which has the Tile, Modified 1 x 1 with Open O Clip only in dark bluish gray instead of black).
Switching out the jumper plate with groove (3794b) to the one without (3794a) yields no additional candidates.

I don't find it clear from the image that there is a groove on those jumpers, if there isn't those parts are old though, but the 2x8 plates also look old gray to me, which would also suggest some age - and neither of those observations conflict with the conclusion that this is not from an official set.

@Henriksupportsthecommunity The old light gray 2x8 has never appeared alongside reddish brown 1x4s and reddish brown cheese slopes: https://www.bricklink.com/catalogItemIn.asp?fromForm=Y&viewMulti=Y&itemType=P&itemNo1=3034&itemSeq1=2&colorID1=9&itemNo2=3710&itemSeq2=4&colorID2=88&itemNo3=54200&itemSeq3=4&colorID3=88&in=S


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EV3 gyroscope drifts when brick is still - what can be done?
The gyroscope value continuously increases/decreases, even when the brick is not rotating! What could be done in order to avoid, mitigate or at least reduce the impact of this behaviour?

*I know that this has been answered a few other times, but it's such a common problem I thought it best to have a dedicated question/answer for it.

This is a pretty common issue called "gyro drift". If the gyroscope is rotating when plugged in and/or when the brick starts up, that constant rotation will be seen as "resting", and when the gyroscope is still, it believes it is rotating.
There are two main fixes to this

Hardware fix
In this, you simply unplug the gyroscope, then plug it back in while holding the robot very still. Any rotation can drift the gyroscope, however, it is pretty simple for most robots.
Alternatively, completely restart the robot while keeping it still. Most of the time this is easier to do, though it takes quite a while.

Software fix
In the software, you can account for the gyroscope drift. Instead of measuring the gyroscope directly, create a variable called gyro. At the start of the program, measure the gyroscope speed multiple times (about 10 should be good for most applications), waiting a small amount of time (try 0.05 seconds) between each, and take the average of the measurements. Then, every second, change the gyro variable by the gyro speed MINUS the averaged gyroscope drift. My preferred method for doing this is to broadcast a message, and have a forever loop in the broadcast receiver, updating gyro and waiting one second in the loop. This keeps your main forever loop free to run quickly.


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Can 9V train motors be linked and work together via the top power stud connection?
I'm building a MOC based on the 10219 Maersk Train, but going for the classic track power 9V system given the removal of need for batteries and slowly increasing availability of new 9V parts from third-party supplier FX Bricks.
I was wondering about dual-motoring my locomotive, and hit upon the idea of using the Technic axled motor from the 9V RC era (as used in the Cargo Train Deluxe 7898 set), linking it to track power via a 9V extension wire attached to the power studs atop it and going to those atop the classic 9V track powered motor.
My thought is that in using the motor with silicone traction tires in addition to the metal-wheeled classic motor bogie, it may be possible to get even better traction and pulling power.
I'm still learning about LEGO trains after getting back into them many years later, so I'm not sure if the transformer could handle it (other folks I've seen have said that the controller overheats running two motors for a long period of time), or if those top power studs can even transmit the power required for running another motor.
Can the components be used as I'm thinking, or have I gone wrong in my thought process somewhere?

The basic premise of your idea is sound: the metal-wheeled train motor can indeed receive power from the track and forward it to the studs on top of it. Then an extension wire can be used to power another motor. The only possible problems I might anticipate are:

possibly mismatched velocity (due to either voltage drop, different internal gearing or different wheel diameter)

the operational limits of the

power supply unit (shouldn't be an issue, as two metal-wheeled train motors can run on a track powered by a single supply)
or the pass-through capacity of the 9V train motor (as it was designed to pass through enough juice to power lights, not motors with their significantly larger consumption)

The good news is that none of these are showstopper issues even if they prove to be a problem, and you can quite easily test all of them - so let's start building :)

Also, besides mismatched velocity, mismatched direction, with 9V this can be adressed by turning one of the connectors 90 degrees (in the right direction it reverses polarity)


text:
EV3 with 6 motors
My son has made a crane with 6 EV3 motors connected to an EV3 hub. He's used ports A,B,C,D and 1,2.
But two of them don't work. Are ports 1-4 just data ports for sensors, not motors?
Is 4 the maximum number of motors?
What happens if we invest in a Spike hub?

On Powered Up hubs like SPIKE Prime, all ports are the same and can be used with motors or sensors. That means you can use 6 motors and no sensors if you need to on SPIKE Prime.
On EV3, ports A-D are for motors only and ports 1-4 are for sensors only. So EV3 is limited to 4 motors (NXT is similar but limited to 3 motors).
EV3 and SPIKE software and motor/sensor hardware are not compatible, so if you invest in SPIKE Prime, you will need to make a new program and adjust your build since the motors don't have the same form factor.
Another alternative could be to daisy-chain two EV3s. This would allow up to 8 motors since each EV3 can have up to 4 motors.

Can't you have two EV3's paired in some way to enable more ports for motors?

Yes, daisy-chaining two EV3s could be a possibility (4 motor ports per EV3 * two EV3s = 8 motor ports).

Perhaps this could be another option on top of the ones you've provided? Getting additional EV3 hub will be cheaper than investing in all new stuff compatible with SPIKE just for two additional motor ports.

Another alternative would be to make a mechanical multiplexer to handle an unlimited amount of motors but this has it's own advantages and disadvantages depending on the project requirements.


text:
Custom Shock Absorber
I have tried making a custom shock absorber, but every option I see uses springs or is too bulky. Is there any way to make a custom LEGO shock absorber using rubber bands? I'm thinking of 6x1 studs with medium stiffness.

Hi William and welcome to Bricks.SE! Can you give more details regarding your goal? What are your dimension constraints, how much weight should it hold, what travel length are you looking for?

I want medium strength, and the dimensions are 6x1

6 as the overall length is quite restrictive, but something like this could be adapted to work if sandwiched between other parts that restrict non-axial movements:

where the black pieces are 1xX plates, red are 1x1 tiles, pink are 2x1 tiles, grey are Plate, Modified 1 x 2 with Pin Hole on Top and the purple line is a rubber band.
The length of the black pieces would have to be negative if the total length needs to be 6, but if the symmetric assemblies can be put besides each other (thus violating the 1 module diameter constraint), then by using 4x1 plates you'd get 2 travel length.

I'll suggest using surgical rubber tubing as the dampening element:

(Photo from flickr)
Surgical rubber tubing is inexpensive and available in several thicknesses, so you can regulate the stiffness of the shock absorber. Just make sure that its internal diameter is 5mm so it fits around a technic axle.
An example assembly would be a 6-stud-long technic axle plus an angled technic connector, a bush, and a 1x1 brick with technic hole:

...then cut two lengths of rubber tubing and place them above and below the 1x1 brick.

If you really want to use rubber bands, then you can leverage parts 32039 (angled axle connector) and 27940 (3L bar with perpendicular pin hole) to add symmetrical rubber bands, like so:


text:
Problem with emulating EV3 brick via wifi
I'm trying to emulate Lego EV3 brick connection via wifi. First I found the repo and rewrote it a bit in C# so now I have this:
LabVIEW.cs
public class LabVIEW
{
    public string Serial { get; set; }
    public UInt16 Port { get; set; }
    public string? Name { get; set; }
    public string Protocol { get; set; }

    public LabVIEW()
    {
        Serial = "001612345678";
        Port = 5555;
        Name = "EV3-rcv";
        Protocol = "EV3";
    }

    public void SpawnConnectThread()
    {
        var udpSocket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
        var localIP = new IPEndPoint(IPAddress.Parse("0.0.0.0"), 0);
        udpSocket.Bind(localIP);
        udpSocket.ReceiveTimeout = 10000;
        udpSocket.EnableBroadcast = true;

        var task = Task.Run(() =>
        {
            var sendStr = string.Format(
                "Serial-Number: {0}\r\nPort: {1}\r\nName: {2}\r\nProtocol: {3}\r\n",
                Serial, Port, Name, Protocol
            );
            var remoteIP = new IPEndPoint(IPAddress.Parse("127.255.255.255"), 3015);
            Console.WriteLine(sendStr);
            while (true)
            {
                byte[] toSend = Encoding.UTF8.GetBytes(sendStr);
                int sentAmount = udpSocket.SendTo(toSend, remoteIP);
                if (sentAmount == toSend.Length)
                {
                    byte[] recvBuff = new byte[64];
                    udpSocket.Receive(recvBuff, 0, 64, SocketFlags.None, out SocketError err);
                    if (err != SocketError.Success)
                    {
                        continue;
                    }

                    Console.WriteLine(Encoding.UTF8.GetString(recvBuff));
                }
                Task.Delay(5000);
            }
        });
    }

    public Socket Connect()
    {
        IPAddress localAddr = IPAddress.Parse("127.0.0.1");
        TcpListener server = new TcpListener(localAddr, Port);
        server.Start();
        var sct = server.AcceptSocket();
        byte[] recvBuff = new byte[64];
        sct.Receive(recvBuff);
        Console.WriteLine(Encoding.UTF8.GetString(recvBuff));
        byte[] toSend = Encoding.UTF8.GetBytes("Accept:EV340\r\n\r\n");
        sct.Send(toSend);
        return sct;
    }
}

And the Main part:
public class Program
{
    public static void Main(string[] args)
    {
        var lv = new LabVIEW();
        lv.SpawnConnectThread();
        var conn = lv.Connect();

        while (true)
        {
            if (conn.Available > 0)
            {
                byte[] buff = conn.ReadLVReply();
                Console.WriteLine(ByteArrayToString(buff));
                if (buff[4] == 0x80 || buff[4] == 0x81)
                {
                    // No response expected
                    continue;
                }
            }

            Thread.Sleep(300);
        }
    }

    public static string ByteArrayToString(byte[] ba)
    {
        StringBuilder hex = new StringBuilder(ba.Length * 2);
        foreach (byte b in ba)
            hex.AppendFormat("{0:x2} ", b);
        return hex.ToString();
    }
}

And some extensions for sockets:
public static class SocketExtensions
{
    public static void SendLVReply(this Socket sct, byte[] dataIn)
    {
        byte[] data = null;
        ushort length = (ushort)dataIn.Length;
        data = new byte[length + 2];
        data[0] = (byte)(length & 0x00ff);
        data[1] = (byte)((length & 0xff00) >> 2);
        Array.Copy(dataIn, 0, data, 2, dataIn.Length);
        sct.Send(data);
    }

    public static byte[] ReadLVReply(this Socket sct)
    {
        byte[] lengthBytes = new byte[2];
        byte[] data = new byte[0];
        int expectedlength = 0;

        sct.Receive(lengthBytes);
        expectedlength = (ushort) (0x0000 | lengthBytes[0] | (lengthBytes[1] << 2));
        if(expectedlength > 0){
            data = new byte[expectedlength];
            sct.Receive(data);
        }
        return data;
    }
}

So what is the problem? The brick is successfully visible in Lego Mindstorms editor (or something, I don't know what it is) but when I click to connect to it, the error appears:

I saw that I received something weird to my buffer after establishing a connection (it was weird because there is nothing in the document about the bytes). So I decided to take a real EV3 brick and check out what are they sending to each other. Using RawCap and opening the result through WireShark I saw that they are "messaging" a lot sending each other different things like the version of firmware on the brick, the name of the brick, the location of my project and so on. Here are the bytes:
after the brick sent "Accept:EV340\r\n\r\n". The PC sends to the brick this
14 00 01 00 00 18 00 8f 60 c0 0c 83 bb 69 17 65 60 d3 0d 14 64 0a
and the brick replies with this
1b 00 01 00 02 5a e5 c5 51 45 56 33 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
and so on

As I said before - there is nothing about it in the communication document.
And I want to say one more thing. If I use the C# library to control the real EV3 brick - there is none of this strange communication after establishing.
So now the question. Is there a way to control or ignore these messages from the Lego Mindstorms editor?

There are two types of commands. "System" commands and "Direct" command. The document that you linked lists all of the system commands but only gives examples of direct commands and does not exhaustively list all of the direct commands. Direct commands are any valid bytecodes to be interpreted directly by the VM running on the EV3, so to completely emulate the EV3, you will need to recreate the full lms2012 VM.
You can find more documentation on the bytecodes used in direct commands at http://ev3.fantastic.computer/doxygen/bytecodes.html (this is documentation from the official LEGO source code that has been built and published by a fan). Beware that the documentation isn't always 100% accurate - you should always check the source code to see how things are actually implemented as well.
There is a machine-readable file of all bytecodes in YAML format at https://github.com/ev3dev/lmsasm/blob/master/bytecodes/data/ev3.yml. This is useful if you want to automatically generate code instead of manually implementing all of the bytecodes.

Thank You so much for the reply. Honestly, I wasn't expecting that this is so difficult. I found the repo and as I undestand the lms2012 folder is only required for me. By now I only want to understand the way of replying the Lego Mindstorms Editor to its strange requests. My main idea is only to reverse engineer the c# library so I would accept only direct commands (like move "the" motor with "the" speed)


text:
Identification of Lego bags with large tan plates, white cylindrical panels, palm leaves and yellow ladders
Can someone help me to identify which set is this from?

Based on Lime plant leaves 6x5 Swordleaf, Tan plate 8x8, Tan plate round half 3x6 with 1x2 cutout, and Trans-light blue panel 3x4x6 Curved top, this set has to be 41374-1 Andrea's Pool Party.

Thank you so much! I think that's the one!


text:
Where can I find the assembly instructions of the chinese Ferrari Daytona gold/black variant?
I bought on Aliexpress a Ferrari Daytona, 1:1 compatible with the original LEGO set, but it's the black/gold variant.
I didn't receive the book, as expected, but I was unaware that the set has no PDF either.
So I'm at the end of pack 3 of 7. The 4th box is where we start to build the front end of the car. I cannot continue to guess which red parts are now black and which are not gold.
Too difficult.
Do you know if a PDF is available somewhere for this variant?
If it doesn't exist, feel free to answer "no", I will upvote anyway.

Given that it’s a knockoff set using stolen intellectual property and made with minimal effort (as evidenced by the lack of instructions), I would highly doubt the existence of a recoloured instruction pdf

Ok, thanks for replying me

So this is my solution to the chinese clones:

Step one is to sort the pieces by color

Step two is to use LEGO's official instructions site to download both high-quality books.

Step three is to build using the instructions as if red and silver were replaced, so this means red pieces are black and the silver ones are gold.

(I haven't done this myself yet so this is just an idea)
EDIT: so this Chinese clone needs a refund to the Ali seller for the instructions supplied by a cloner (a cloner has more steps in same pages than LEGO was).

I undestand. I am now at end of book 3, where I built the front end, and It is now not so hard as I was supposing. Not relaxing, at all. but not hard. Thanks for replying.

Note that presumably not all pieces have been color-swapped. Most probably the Technic connectors and axles have retained their original color-coding (if the IP thieves were attentive enough to copy that as well).


text:
How to find this LEGO part name? For connection of Technic bricks and steering liftarms
I have checked Bricklink for Lego Technic but still can't find it's name.

This is part# 32069 or 64920: Technic, Steering Arm with Pins.

Found by looking at the (relatively short) list of parts in Bricklink's inventory under the Technic, Steering category.

Thank you a lot!


text:
Got a weird trans-purple cone part as extra in 71043-1 Hogwarts Castle
I bought a 71043-1 and one of the extra parts is this trans-purple "cone" with the smaller through-hole, which couldn't identify since there is no element number, only the mould number which is 05-B01.
Here's a picture, (normal stud as a comparison) - please help me identify or give an element number for this!

It looks like a "short shot" of Minifigure, Utensil Bottle, Erlenmeyer Flask with Trans-Purple Fluid Pattern (pictured below) which is included in the set. I would even say it lacks the Trans-clear "coating" around Trans-Purple piece of the combined element.

Short shot - is a term used in LEGO community to describe an uncommon occurrence of plastic element production, where element is produced with insufficient amount of plastic. There could be various reasons: temperature is too low, lack of plastic supply and other errors during production.

Yeah, I was supposed to say the same. This is must be the origin of the part and how it ended in the same bag as the flask. Somekind of premold and inner piece for the flask since both even have the center hole in them, that would also explain why it has a mould number but no element number. Pretty cool since this must be crazy rare because in all of my 20 years of legos have I ever seen such occur on my sets!

I wonder if that's the entire inner purple part prior to the clear plastic jacket being molded around it.

I wonder how much money an error piece like that would be worth?

Same here, market for these kind of occurrences are probably very slim so the pricing most likely is what the seller asks for so in other words priceless, only this time quite literally :)


text:
Bluetooth connection between an Android phone and EV3 brick?
I've paired my phone to the brick, however I was wondering if there were any resources out there regarding a simple android app to type something out on my phone and output it on the robots LCD screen. I am new to the scene and I have not found any resources for it.

MIT App Inventor is a popular way to make simple Android apps that can communicate with an EV3. It has special blocks just for EV3.


text:
Connecting EV3 with older motors using conversion cable
I'd like to use an EV3 brick to power an old 9V motor (74569). To do so I'm going to get one of these conversion cables (x1676) but I'm not 100% sure if it's possible to control the speed of the motor with it. I'm aware of the limitations of these cables but RPM control is crucial to my project. These cables became quite expensive nowadays so I don't want to waste money on them.

Hi Adam, I have provided a link to the conversion cable you are asking about, but I can't find any motors or other parts with the 74569 identifier. Could you please check if you got the number right, or alternatively link the motor similarly?

@zovits, 74569 is the lego id for the 9-V motor, see here: https://www.philohome.com/motors/motorcomp.htm

@MichaelVerschaeve thanks, neither Brickset nor BrickLink knew about this ID, which is quite strange. I have added the relevant link now.

Does this answer your question? Lego RCX to NXT converter cables not working properly with EV3

Not entirely a duplicate imho, the other question and answers do not reflect on suitability for speed or positional control.

You'll be able to control the 9V motor as an unregulated motor with the similar named motor block, you'll be able to set the speed approximately, but any accurate RPM control is out of the question as there is no feedback pulse signal from the motor to the EV3 telling it how fast it is going.
Also there are some programming quirks with this cable and an EV3, like having to specify two motor blocks as the first one is ignored, but I don't recall the specifics.

This is correct. Emphasis on the fact that the cable will work as expected, but the motor is inadequate for OP's purpose. A motor with no encoder can't provide any feedback.
Also, this details the "programming quirks" that were mentioned: https://bricks.stackexchange.com/a/15342/6720


text:
How does the 8365 Tuneable Racer work?
The set 8365 Tuneable Racer has tunability as its main feature, meaning the motor's parameters can be changed by adding, removing or swapping certain additional elements. However, these parts seem to be purely cosmetic, and not in any way mechanically or electronically relevant.
The instructions illustrate their intended functionality:

And similarly with the B-Model:

Based on these images, the functionality of the individual parts seem to vary in different combinations, as the last two setups for the A model hint on

having better performance than

but the B model seemingly has it inverted.
So how does this set work? My current best theory is that there are buttons inside the technic holes used to connect these parts and their states affect the motor's characteristics somehow, but I'd like to know if someone has better insights into its workings.

The first two images for the B model suggest different capabilities for the same setup, which must be an error on TLG's side, or is there something I have missed?

Edit:
This Polish forum has a review of the set with an image depicting the switches inside the Technic holes:

The text states (as translated by Google):

it can be seen that in the places where the pipes are to be finally inserted, there are buttons that control the engine's operation.

can be tuned using regular pins, using them as jumpers

This eliminates the "rotating pins providing resistance" theory, but I'm still looking for any experimental results, authoritative information or preferably a full analysis of the different combinations regarding speed and torque.

The varied horizontal positions of the B model suggest that the different combinations affect speed differently to the maximum climbable slope. The last 2 configurations of B model seem to have consistent speed effect as A model

I do not own this item, but observing the pictures leads to a logical inference.
The pins are in different locations.
If you look at parts, you will see that they are 5 pins wide.  One part has pins in positions 1 and 5, the other has pins in positions 2 and 3.
You then connect the parts to the motor.  With switches inside the motor, it can detect which holes have pins in.  This is similar to how the LEGO Super Mario figure knows which Power Up is attached - a simple way to test would be to attach normal pins in those locations, rather than the special parts that came with it.
This may not even be electronic, the pins may be physically changing the gear ratio inside the motor.  Which answers the last part of your question:  why do the performances appear to be reversed?
Because a high gear means lots of speed, but no torque (power), and a low gear means low speed, but lots of torque (power).  You can test this yourself on a bicycle.  On a flat path, a high gear will let you go really fast, while a low gear will mean you are slow.  But, going up a hill, a low gear will let you easily climb steeper hills, and a high gear will leave you stuck, exhausted, at the bottom!  So, the "high gear" item gives better performance on the "speed"/"racing" model, but the "low gear" item gives better performance on the "power"/"steep ramp" model

Wow, I completely missed the fact that the pins are different distances apart...

I don't own the set (or parts), but I might have a guess.
Of the two exhaust tubes, one seems to have pins that can rotate, and the other has fixed pins.
If the engine block they attach to outputs some of the torque to those pinholes, then attaching the exhaust parts adds resistance, therefore redirecting torque to the wheels.
The exhaust can then be configured in 3 ways;

Without tubes, providing no resistance
With single exhaust tube, providing some resistance
With triple exhaust, providing maximum resistance

The same theory could apply to the air intake, but I'm not sure how it would make it better at hill climbs. Perhaps some fancy gear ratio magic. If I get my hands on one I'll definitely try to take it apart.


text:
What is the history of the set numbers of Lego sets through time?
I was wondering how Lego went from a 4 digit code to a complete family and set of products to identify them like the Creator set, the System set...
Of course part of it is their growth but does anyone have more information on how the product code changed throughout the years?

There is nice article on Brickset called "The history of 5-digit set numbers". While this article is not a historic information on transformation it is still quite interesting read since it is based on data collected by the website itself.


text:
Which set are these 3 LEGO bags from?

I've got 3 bags.

On the bag 1 it says 529r9
Bags 2 and 3 says 629r9

Is there any way to figure out what set are these bags from?

Those codes only indicate when the bags were filled (5th and 6th day of week 29 of 2019 respectively) and give no information about the set itself. Can you attach a picture of the bags so we can identify the set by the pieces in the bags? Thanks!

Just added! Thanks!

It's Harry Potter set 75947 (Buckbeak's rescue).

How did you find out?

@til_b The wings  might have helped.

I actually looked for the umbrella first, as there are a LOT of pieces named wing and I wasn't at all confident I would get the right one. But one of the few sets with a pinkish umbrella was a Buckbeak set, so I looked at the inventory, and it had big wings that looked the same. And it turns out that is the only set that has that particular type of wing in that color. As the cellists say, viola!

Maybe I'm not remembering the movie very well, but it's odd that the guy with the axe looks like Darth Vader...

@DarrelHoffman: The resemblance wasn't striking in the movie https://harrypotter.fandom.com/wiki/Executioner?file=Walden_macnair.jpeg

@EricDuminil Indeed, I'm just wondering if the people who designed this set just used a Darth Vader helmet instead of creating a new piece because it's "close enough"?


text:
Volvo Articulated Hauler (42114) doesn't operate the bucket
I cannot get the rams to lift or lower the tipper body. I suspect it has something to do with the clutch mechanism since all the shafts and gears rotate freely until the clutch is connected. The white clutch mechanism seems very stiff to turn. Is this normal for this clutch in a new set?
I can get the hauler to drive and steer ok but it won't operate the loader.

Two steps below are taken from first instruction booklet for the 42114 set. Since one end of the clutch is locked it basically tells, that under normal conditions, clutch should not be spinning at all. Clutch is used as a safety feature within the build, when something get stuck, not to cause further damage to gears or human flesh. So in this case it should only begin spinning if the rest of the gear train is having issues.

I'm not entirely sure what could be causing your issue of bed not operating, but I suspect one other tricky place could be the reason. Please pay attention to the location of 20 tooth bevel gear for each side (highlighted in blue) in the pictures below. One of these needs to be on top on one side and on the bottom on the other. If placed in the same direction, one side will pull while the other will be pushing.

I built this project and found that I also had issues with the build. After several rip-aparts and tests, I discovered what I believe many are messing up on this build.

The early steps of building the gearbox are crucial to later success.

Once you get the gearbox built, but before you have connected the motors, operate everything manually to ensure that the purple clips and the orange shifter are aligned as shown in the diagram.

Also, be sure that each of the shift rings is connected properly to the orange shifter. You can test this by rotating the purple shift actuator axle above and ensuring that all 3 shift rings move accordingly.

Don't forget the extra red gears at the end of the gearbox assembly. If you have extra gears sitting in a bag at the end of bag 1, you probably did something wrong.

The shifting works as follows:
There is a Park Gear at full clockwise for the purple clip. It will be at the bottom. This is also where you can operate the dump function.

1st gear is 90 degrees counterclockwise with the purple clip away from you.

2nd gear is with the purple clip straight up.

3rd gear is with the purple clip flat and towards you.

Once you've fully assembled the model and connected the cab to the rear unit you can test to be sure that everything functions correctly.
Be sure and do a recalibration if you changed anything in the gearing.
I had forgotten that there is a 3rd differential hidden underneath the yellow 3x3 / under the dump function gearing in the center. If you don't connect the cab or alternately connect a geared load to the center shaft, nothing will operate and you'll wonder why.
Hopefully, these more detailed instructions will get you unstuck and you'll be operating your truck in no time.

Whenever you refer to the instructions, could you include the exact step numbers (to make it easier to understand what part of the build you're referring to). You might even include images from the instructions for extra clarity. If I understand correctly, your points 2 and 3 refer to step 42 on pages 30 and 31, and your point 4 refers to step 50 ? And the "3rd differential" is the one from step 95 ?

A video showing the dumper drive running forward (up) and backward (down) can be seen here. I didn't make the video but it helped me correct the problems I was having with my build. https://bricksafe.com/pages/VermontDave


text:
Why do Technic beams have an odd number of holes?
Why do LEGO Technic beams tend to have an odd numbers of holes?
Is it for making it suitable for designing models? Or does the owner of The LEGO Group love either odd or even numbers?

It's to make them fit with the original Technic bricks which have an even number of studs and the holes go in-between.


text:
Could Microsoft MakeCode be an alternative to the EV3 program?
Is it possible to use Microsoft MakeCode for the EV3 as an alternative to the widely used EV3 program by LEGO? What are the benefits and drawbacks?

What is "good" is a matter of opinion. Perhaps you could define more specifically what you consider to be good or certain features you are looking for?

I have edited the question to be more objective and thus avoid getting it closed as opinion-based. If you feel this edit has changed the intention of hte question too much, feel free to either roll back or edit it further to better convey the original intent.

thanks for the feedback!