The initial rover chassis was an old radio controlled buggy which belonged to someone in the office - it had some impressive wheels, an MDF structure which allowed an RS-EDP to sit neatly on top of it and two pairs of decent motors which could be driven from the RS-EDP-MC1 motor control modules.
Unfortunately it was missing some bells and whistles including quadrature encoders - I ended up making my own using some QRD1114 IR sensors and a code wheel generated from this useful website. It was definitely an educational experience building a pair of encoders from scratch (and also allowed me some nostalgic use of pritt stick when putting the discs onto the wheels) but at a very modest 20 counts per revolution and rather bespoke implementation it wasn't the best way to show it off!
In order to make the platform more aesthetically pleasing, robust, and reproducible, I decided on a commerical off the shelf solution for the chassis which came with motors that had quadrature encoders built into them. This made the design much sleeker and more compact.
The chassis I chose was the The Stinger Robot Kit by Robotics Connection.
And now for the before and after pictures:
Before
After
Before
(All those wires are just for the custom quadrature encoders!)
After
Before
After
Please excuse the engineering mess as this is still a work in progress - I'll get some nicer "display" photos when everything has been wrapped up.
In my next post I will talk about some of the software used in this design, mainly the Quadrature Encoder Interface library for the mbed.
Other posts in this series:
1. Introduction
2. Chassis
3. Quadrature encoders
4. PID velocity control
5. Inertial measurement unit
6. Rover State Machine
7. Conclusion
8. Technical Details
Aaron Berk
The old chassis [in yellow] had 4 QRD1114 IR sensors to make up the quadrature encoders.
One encoder has two tracks, each of which require a QRD1114 to read it.
There were two encoders, one on a wheel on each side thus making 4 in total.
Kelawan Sor ...
I have a question.
-How many qty.our some QRD1114 IR sensors used for this project?.