Building an Open Source Self Balancing Scooter

Malcolm Faed malcolm@faed.name

Copyright: This document may only be reproduced with the author’s permission.

Introduction

In recent times, advanced electronic systems have become cheaper and cheaper and at the same time become more complex. The price of the components are now within reach of the hobbyist (e.g. Gyro and Accelerometer). This allows more complex systems to be built at relatively low cost. And most important these advanced technologies can be used by individuals and hobbyist where they were previously only available to more wealthy individuals and corporations.

This is also an excellent example of Peer to Peer Development that brings together people from different continents and backgrounds to develop a common product.

This is a project I had contemplated for quite a few years since first seeing the Segway on the Internet. I saw and had a ride on Geoffrey Bennett's home made scooter at the Linux Conf in 2007 in Sydney. he also offered the source code on his web site which was going to be the hardest part for me.

This project marries several of my passions, Electronics, Mechanics, Control Systems and Software.

Obligatory warning. Build this at your own risk. If you injure yourself or any one else its not my fault.

Parts List

Total ~ AUD$550

Chassis

Batteries

>

Motor Controller

Microprocessor


Sensors

Gyro and Accelerometer from http://www.sparkfun.com

Which way is up?
ADXL203 Precision ±1.7 g Single/Dual Axis Accelerometer 1 v/g

How fast am I tipping?
ADXRS401 ±75°/s Single Chip Yaw Rate Gyro with Signal Conditioning

Current Sensor – hall effect device and iron core.

 

Software

Balancing

(Adapted from Geoffrey D Bennett presentation)

Turning

Measuring the platform angle

(Adapted from Geoffrey D Bennett presentation)

Over Speed

(Adapted from Geoffrey D Bennett presentation)

Misc.

(Adapted from Geoffrey D Bennett presentation)

Future Improvements

Links, credits and inspirational people.

This project would not have been possible without the assistance of the following people.

Geoffrey D Bennett – for the source code and tuning software
http://www.netcraft.com.au/geoffrey/meta

Trevor Blackwell
http://www.tlb.org/scooter.html