Constructing a robot to solve the Rubik's bot

Dayan GuHong 3x3 Cube de vitesse

Alternative: Dayan Cube

dimension	min	max
size in cm	5.65	5.65
weight in grams	50	100
cube size in cm	1.8	1.9

Robot design

We decided to inspire ourselves from the current world record for rubiks cube solving (click on image to see video of a resolution):

We did not look for plans or schemas online of their solution as we wanted to solve these details ourselves

Choosing Parts

Basic architecture of the wiring for:

• Rasberry Pi
• Driver
• Motor
• Alimentation

https://makersportal.com/blog/raspberry-pi-stepper-motor-control-with-nema-17

Motor

Testing the weight needed

1. The Paprika bottle weights 120g
2. The Cream box weights 140g

Weigths:	120g	140g
Results:	FAILURE	SUCCESS

Calcul of the moment needed to rotate one face of the Rubik's Cube

Conclusion

• We need a motor with a moment of 4 N.cm

• Here is a motor of 40N.cm (with it's driver) we will use for testing: Nema 17

Stepper motor Specification	Value
Manufacturer Part Number:	17HS4401
Motor Type:	Bipolar Stepper
Step Angle:	1.8 deg.
Holding Torque:	40Ncm(56.2oz.in)
Voltage	24V
Rated Current/phase:	1.7A
Frame Size:	42 x 42mm
Body Length:	40mm
Shaft Diameter:	5mm
Number of Leads:	4
Weight:	280g

Stepper Driver Specification	Value
Supply Voltage	9V-40V DC
Max output current	4.0A
For step motor	42, 57, 86 type 2 phase 4 phase (4 / 6 / 8 line)

Alimentation

Basics

• Voltage
  • The difference in charge between the two points
  • Voltage is supplied
• Current
  • The flow of electrical charges
  • Current is drawn

How to choose power supply for electronic project SeedStudio

Formulas:

• Power:

  • 
    • P = Power (Watt)
    • I = current (Ampere)
    • V = voltage (Volt)

• Ohm's law

  • 
    • V = voltage (Volt)
    • I = current (Ampere)
    • R = resistance (Ohm)

For a motor taking 24V/1.7A = 40.8 Watts

This alimentation will allow for testing:

Alimentation 110/220V DC 24V 15A 360W

It gets 24V out and allows to get out up to 360W. Amperes seems to not matter as they are defined by the 'receiving appliance'

Setup

Tutoriel used : https://danielwilczak101.medium.com/control-a-stepper-motor-using-python-and-a-raspberry-pi-11f67d5a8d6d

port GPIO: https://deusyss.developpez.com/tutoriels/RaspberryPi/PythonEtLeGpio/

sourceforge doc: https://sourceforge.net/p/raspberry-gpio-python/wiki/Examples/

https://projects.raspberrypi.org/en/projects/physical-computing/1#:~:text=The%20GPIO%20pins%20allow%20the,%2C%20the%20temperature%2C%20and%20light.