Why don’t I look at the basic robots provided by ROS and see if it’s easier to reverse engineer them?

This probably should have struck me earlier, but I’d got involved with getting face detection working and was really quite enjoying it.

It turns out that the ROS Turtlebot used in the basic tutorials, has a physical counter part, also call turtlebot and is (will soon be in Europe) for sale. This platform is based on the iRobot Roomba (500 series?) vacuum cleaners.

Now I also don’t have a Roomba, and I’m not going to spend (well let’s face it, the wife wouldn’t sign it off) £200 odd on a robotic vacuum cleaner to then hack it apart for an experiment.

However the Roomba and Create both use Open Interface which handily has a pdf Protocol Document available.
I did a bit of searching online, and could find a few Arduino based libraries to control Roombas, but not to emulate them.

So off I went and wrote this Open Interface Arduino Library.

Today it is a pretty complete implementation, it handles communication with a controller that thinks it’s talking to a iRobot device using callbacks to allow a developer to handle the driving, song playing and sensor interaction in their own way.

I’ve tested this with my own bot, which is based on a 1984 Tomy/Tandy Omnibot/Robbie Snr toy robot. I have it driving around controlled by the ROS Turtlebot vanilla implementation, no problems at all

Now I’m not a C++ coder by any standard, so if someone would like to comment/code review/tear to shreds, please do so. I won’t be offended (much).

I’ve back dated a load of the updates, as I’d been meaning to post blog entries about the work, but hadn’t gotten round to it.

So far I have a 3d design worked out a working prototype circuit and a full breadboard circuit also designed.

I’ll try and put up some full photo’s soon and maybe even some video of the prototype.

A couple of new Arduino shields, namely a motor driver board and a wave shield, although I’m actually planning on using the wave shield on a children’s toy (possibly).

I spent a decent part of a day, last weekend, stripping old hard disk drives, CD ROM drives, floppy drives and old mice for components. Stepper motors, brushless DC drives and various other juicy hacking hardware.

I’ve also been looking for a guide on how to power and control a 5400rpm hard disk spindle motor.
It has four contacts, one ground and three coil energising connections.

Similarly to a stepper motor, these connections should be connected sequentially, the frequency of the pulses will allow you to control the spindle speed with high accuracy.