LEGO Robot Inventor 51515 Rubik's Cube Solver

My son (10) has done the mechanical part by using PrimeCuber instructions and (only!) the Robot Inventor 51515 parts. I am more than satisfied with the results. :)

If it is not corrected yet, in the instructions it says "Original concept: Mladen". Well, not really. The original concept is by great David Gilday. My son Marin has adapted the Prime build and I have adapted the code.

You should read the instructions included in the GitHub README.txt. In case of scanning problems, you could try the updated program for testing (CubeTestScan).

The Python code is copied from the LEGO SPIKE app to the Mindstorms app. I have installed the LEGO Education SPIKE app, opened PrimeCuber projects (without connecting the hub) and C&P-ed the code to empty Python projects in Mindstorms app.

The main code worked with the Mindstorms FW but the parameters for the scanning arm had to be changed as the design is quite different than the original (the part 6302830 rack 13M is missing in the 51515 set). The large solving table could not be loaded for some reason, but I have not investigated as it is optional, and the solving is fast enough without it).

If you add a photo of your build to the album, my son and I will appreciate it. :)

Some troubleshooting info:

After the solving program is started, the left/right buttons on the hub can be used to correct the cube cradle position - before a cube is inserted.

The cube used in the video is "Giiker M3" (supposedly a Xiaomi brand). It has magnets so it snaps properly in the position every time. Magnets really help!!! Apparently, there is also a Bluetooth version of the cube, but it is not necessary.

After the solving program is started, a pixel will be lighted near by the offending port if the expected motor/sensor is not found.

If there is a problem with scanning or tilting the cube, check if the cube cradle is in the right position. If it is one hole closer to either scanning or grabbing hand, the scanning and tilting *almost* work.

We had a case where the color sensor cable was too tight. Also, the top of the grabbing hand can be made almost right, but not quite.

The most common problem is with scanning. If the cube cannot be scanned properly, after three tries an up-left arrow will appear. The problems are typically mechanical. Do not worry there is no orange among the "standard" colours as the scanning uses RGB values. Also, the big LED colours do not correspond very well to the colours on the cube.

If there are scanning problems, it should be checked if the build is solid enough on the gears side. The gears should not skip. Sometimes, more or less light leads to more accurate scanning.

The scanning arm movements are quite jerky. In case of scanning problems, maybe a rubber band fix will help. There is a picture in the photo album where a face mask band is used to tension the arm a bit.

I hope this helps. Please let me know in the comments if you build it and it works! :)

[IAssemble]

Well done Mladen and your son. This is a great adaptation of PrimeCuber for the MINDSTORMS Robot Inventor set! :-)

[termi]

This build is awesome i built it and it's so cool thanks for making this cool version with the robot inventor.

[km_]

Невероятно круто! Нет слов... Будем повторять и исследовать)

[timandjoshbricks]

Amazing! Can't wait to show this to my son!

[simpleanimations]

That pile of fricking legos is smarter than me ):<

[heimdal]

I love this model. it is similar with the last 2 generation!

[AaronGreenberg-rv]

Tell your son that he did a super good job! :)

[silvertakana]

If the robot have a face, he would probably be having a victory smile on his face!

[cptnroman]

I'm having problems with the colours scanning properly. Sometimes, my camera detects yellow as orange and orange as red. Is there a fix for this? If not, what cube did you use in this video?

[zacharykohoutek]

Could you please make a tutorial on how to make it and the coding of it?

[synkron]

This really does prove that the possibilities of LEGO bricks are endless.

[khansgaming]

thnxs for showing the simpler versoin :)

[okubo]

can the code given in the description be used in EV3 31313 set too?

[thefuturerex]

That’s cool dude keep on making stuff like this

[WebleRobot]

I just realize that the robot thing is made out of Legos

[feynxro]

Hi, I'm also just starting out with the Lego Youtube thingy, I've subscribed to you cus I've got your video recommended and I was thinking what would you say about mine, I think u have a bit more experience than me already, thanks and cool video btw, I'd just upgrade the lighting to a softer option

[MRG-]

Can you guys make a faster one? good job btw

[thevrsamurai]

I built everything but when it is done with the loading image it turns off, do you know what is happening?

[claudiabasler]

can you give the instructions for your model

[footoslin]

Nice! But what do I have to change for 51515?