Coobycs - Rubik's Cube Robot Solver

Description

Check the Files section for a video!

I've been fiddling with Rubik's cubes for years and after building a cube solver with Lego I wanted to built something more robust and 'professional'.
A while ago I saw a post on Reddit and I really liked the design but unfortunately no other details were given so I decided to build my own version and publish this to help people looking to build something similar.
It's using a NodeMCU, Nema17 stepper motors and DRV8825 drivers + v-profile and various connectors(some of which are 3d printed) for the frame. I designed a custom PCB to make everything nice and tidy.

Files

Coobycs.mp4

A video of a full solve of the robot

MPEG-4 Video - 13.36 MB - 03/04/2023 at 16:50

Download

Coobycs NodeMcu SRC.zip

Source code

Zip Archive - 9.48 kB - 03/04/2023 at 16:16

Download

Coobycs PCB.zip

Gerber files for the PCB

Zip Archive - 75.21 kB - 03/04/2023 at 15:41

Download

Coobycs STL.zip

STL files for 3d Printing

Zip Archive - 19.24 kB - 03/04/2023 at 15:31

Download

Components

6 × Nema17 motors with wires

6 × DRV8825 drivers

1 × NodeMCU v2 or similar board

6 × Capacitors 100 uF, 63 V or similar

1 × Power switch

Build Instructions

Collapse

1

3D Printed Files

The v-shape profiles are connected on the outer corners with 90degrees connectors you can buy but for the top/bottom and middle sections, I designed in Tinkercad some connectors you'll have to print. You can find the files also here: https://www.thingiverse.com/thing:5890181

Print 2x 4 way connectors and 4x 2 way connectors. Print 6x axe connectors that you'll later glue to the center pieces of the cube.
2
Building the Frame
Frame

The frame is based on this reddit post a saw a while ago and I really liked(unfortunately no details were provided so I made my own).
- Middle: Connect a 7.5cm and a 12.5cm profile with the 2way connector. Repeat 4 times.
- Top: Connect 4x 10cm profiles with the 4way connector.
- Bottom: Connect 4x 7.5cm profiles with the 4way connector.
Use the metal 90degrees connectors to connect the top bottom and middle.

Motors
- Insert the motors into the 3d printed connectors and secure them with the screws.
- Connect motors and the axe with the shafts couplings.
Rubik's Cube

Glue the axe's ends to the cube's centers and you'll have to make a few adjustments to get everything fit snuggly.
3

Electronics

Here is a schematic that you can use to connect your development board to the motors and drivers.

As you can see there are quite a few cables and it can get quite messy if you try to use a breadboard.

To solve this I developed a custom PCB to handle all this. Note that the PCB is designed for a NodeMCU v2 quick drop in.

The Gerber files you can find attached and you can use a service like https://www.jlcpcb.com or https://www.pcbway.com to order a custom PCB

Once you have the PCB, you'll have to solder the capacitors, pins, power connector and switch. The motor drivers and NodeMCU are dropins.

Note that each driver has a level which mentions which face/color of the cube it will connect to. Use these label to orient the cube in the frame and connect the motor cables.