Ball Balancer

Acknowledgements & Credits

This project is heavily inspired by and built upon the open-source work of Aaed Musa (Ball Balancer on Instructables).

Python scripts to log data and graph visualizer are generated using Claude Sonnet 4.6.

Major changes (compare to original work)

• Use STM32F4 "Blackpill" instead of Teensy 4.1.
• Use STM32 firmware development tools instead of Arduino (using Hardware timer, FPU, ...).
• Re-design R-joint so it does not slip (mismatch step when working).

Development

Pre-requisites

• Python 3.10 or higher (with matplotlib, numpy and pyserial libraries)
• STM32CubeMX
• STM32CubeCLT
• OpenOCD
• Clion (preferred)
• ST-Link V2

It's also possible to use STM32CubeIDE, but CLion is recommended for better coding and debugging experience.

Firmware

All firmware code is located in the firmware directory. The project is configured for STM32F411CEU6 "Blackpill" microcontroller.

Scipts

To log data to terminal only:

python loggger.py

To log data to terminal, draw graph x_err, y_err, x_out, y_out and save to csv file:

python live_debugger.py

To see the graph of the logged data from csv file:

python log_viewer.py --file logs/xxxx-xx-xx_xx-xx-xx.csv

PID Tuning Tracker

Times	Time	Kp	Ki	Kd
1	2026-06-09_14-49-30	6E-4f	6E-5f	10E-6f
2	2026-06-09_16-08-42	1.3E-3f	7E-5f	2.3E-5f
3	2026-06-09_16-36-50	1.1E-3f	5E-5f	2.3E-5f
4	2026-06-09_16-38-50	1.1E-3f	5E-5f (x) / 7E-5f (y)	2.3E-5f
5	2026-06-09_16-54-01	1.1E-3f	5.5E-5f (x) / 7.5E-5f (y)	2.3E-5f
6	2026-06-09_16-58-05	1.1E-3f	6E-5f (x) / 7.5E-5f (y)	2.3E-5f

BOM

ID	Name	Quantity	Description
STM32F411CEU6	STM32 BlackPill	1	Microcontroller
	Resistive Touch Panel	1	4 Pins
17HS4401S	Stepper 42x42mm	3	1.5 - 2A
TMC2208	Stepper Driver	3
LM2596	Voltage Regulator	1	4 - 35 VDC Input, 1 - 35 VDC Ouput (3A)
	Capacitor	3	35V - 220uF
	24V power supply	1	24V - 5A
	Terminal Connector	1	15A - 12 Ports
	FPC/FFC to DIP Adapter Board	1	4 Pins
	DC Jack	1
	USB to TTL	1
	Male and female header pin	many