Let's Make Robots!

Autonomous Recycling Robot

Autonomously navigate, find objects, sort and store them.

This was my first robot since the days of Lego Mindstorms 1.0. It was built as my senior design project. It follows all the rules to the IEEE SouthEastCon 2009 hardware competition. It would have easily won, had it had the chance to compete.

It is built from the ground up, starting with the guts of a Irobot Create. I was in charge of all the electronics, as well as a good portion of the programming.

It autonomously navigates and finds objects using a scanning Sharp IR behind the main scoop. There are 5 IR reflectance sensors in the scoop that measure the height of the objects it collects. Then, the three different types of objects are sorted and stored on the robot.  It travels with a random walk if no objects are scanned, and is bounded in the playing field by a electric fence detected by a sensor that I designed and built. 

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   I would love some more information on the electric wire fence... Schematics,links whatever you can provide.. I have spent months trying to get it to work properly with no real results.

The fence itself was provided to use as part of the competition. I do know it was a 10kHz sawtooth wave. I think they used an Op Amp or two to generate the sawtooth wave, and then ran that through the wire loop, and through a resistor in series with the loop. The current through the loop at 10kHz is what generates a detectable EM field.


I did design that sensor we used to pick up the wire. I'd have to really dig for the schematic, but I can tell you about it. The sensor probe itself is an inductor. The EM field generated by the wire fence will cause a current to generated in the inductor, which we tie a resistor across the two inductor leads so the current creates a voltage across the resistor. That voltage difference is amplified by an Op-amp, and then filtered by a bandpass filter set to pass only the 10kHz signal. Then we rectify and limit the signal to 5V using diodes and read it with an ADC pin on the Atmega.