Steady!

A custom double-inverted pendulum that balances using a rack and pinion powered by a motor.

it uses:

• a 12v DC motor
• a Teensy 4.1 to run a 2kHz control loop
• 2 Time-of-Flight sensors to determine cart position
• 2 Absolute Magnetic Encoders to determine rotation of both joints of the arm

i made this project to learn more about cad and that was a big success! everything in the assembly works great, fits together with zero overlap. i learned when to use parts like bearings, how to create good mounts for parts even in awkward positions (like the second encoder), and how to use relations properly in assemblies to create proper movement.

Render

CAD:

https://cad.onshape.com/documents/bdb7c14a6d723ab75184049c/w/bbc527d9ae0d21a2dad8c051/e/2942f8800dd81ea3c4a498f0?renderMode=0&uiState=6a42af40a9e76bdc7da518a3

Wiring

BOM

Name	Link	Price (CAD)
12V DC Motor	https://www.aliexpress.com/item/1005009213371004.html	6.40
M1 8mm 26T Gear	https://www.aliexpress.com/item/1005007675028501.html	10.48
HGR20 400mm Linear Rail & HGH20CA Guide	https://www.walmart.ca/en/ip/Linear-Guide-Rail-HGR20-400mm-Linear-Guide-Linear-Rail-Block-Linear-Motion-Rail-Reliable-and-Durable/0YP32M7YFV2T	67.59
10mm ID Shielded Flanged Bearings	https://www.aliexpress.com/item/1005006018219987.html	12.78
2x VL53L0X TOF Sensor	https://www.aliexpress.com/item/1005012456139246.html	7.30
1M 10x10 400mm Rack	https://www.aliexpress.com/item/1005006480368834.html	18.99
2x AS5600 Magnetic Encoder	https://www.aliexpress.com/item/1005007718766639.html	14.00
Teensy 4.1	https://ca.robotshop.com/products/teensy-41-usb-microcontroller-development-board-no-pins?variant=42412252823703	60.13
DRV8874 H-bridge Motor Driver	https://www.aliexpress.com/item/1005012021782010.html	10.57
12 2A Power Supply	https://www.aliexpress.com/item/1005010390772322.html	5.29
12v to 3v3 Regulator	https://www.aliexpress.com/item/1005005691344779.html	1.70
	Total (USD)	150.66