Balancing Robot Vehicle

I used this guy's YABR (Yet Another Balancing Robot) project as my guide: www.brokking.net/yabr_main.html

I used his code with some slight modifications:
- uses NRF24L01 radios instead of bluetooth to Nunchuk
- uses the pin mappings of my CNC shield whereas he directly wired to his DRV8825 drivers
- added incr/decr buttons for P and I and D to help to tune the PID variables.

My code is here:
https://github.com/nshaver/balancing_robot_vehicle/

Components:
2 x Arduino Uno (one for vehicle, one for joystick) - $20
1 x CNC shield - $5
2 x DRV8825 Stepper Drivers - $10
1 x MPU6050 Gyro/Accel - $5
2 x NEMA17 1.7A stepper motors - $25
2 x NRF24L01 2.4ghz radio with external antenna - $10
2 x NRF24L01 breakout adapter (converts to 5v) - $5
1 x Funduino Joystick - $10
2 x Wheel+Tire 12mm hex - $15
1 x Matek Duo power supply (12v for motors, 5v for Arduino) - $20

Everything above can be purchased on Amazon, probably Amazon Prime. If you enter exactly what I have for my description into your Amazon search you should be able to find the product.

2 x 3d printed wheel adapters
https://www.thingiverse.com/thing:270...

1 x 3d printed Kobalt battery adapter
https://www.thingiverse.com/thing:230444

The controller code is also at the link above.