BEAM robots

jiristepanovsky.cz

BEAM robots - 2009

I was first introduced to the art of engineering through BEAM robotics. At the time, I have not really been able to design anything, I have not understood electronics, nor could I write software. Regardless, I was fascinated with BEAM robots and I successfully built a couple of them. All of them are based on simple analog circuitry and are usually powered by sunlight.

My first attempt used polycrystalline solar panels from calculators and a common BEAM robot circuit that monitors the voltage on a capacitor. When the capacitor is charged to a certain threshold it powers a small motor, propelling the robot forward. Under direct sunlight it worked quite well... even though, it was very, very slow.

My second robot was conceptually the same, but I used single crystalline silicon solar panels instead of polycrystalline ones. They produce noticeably more power but, to get sufficient voltage for the circuit to work, you need about five or six of them in series. Since they are thin and brittle I've managed to break a couple of them into pieces, so I've picked up the fragments and used them.

Once I had mastered the basics, I was able to build a bit more complex robot that moved toward the Sun and was meant to avoid obstacles using whiskers (tactile switches). The whiskers did not work very well, as they rarely made good contact with an obstacle. The Sun following, on the other hand, worked like a charm.

During winter, the Sun was too weak to provide enough power, so the next BEAM robot had to carry a battery. It used LM386 and two photodiodes to follow a light source. Sadly, it never worked as intended and I was not skilled enough to find the cause.

A better (working) version of the previous robot used a rechargeable battery and 74HC14 chip with a couple of green LEDs (used as photodiodes). It beautifully followed the light source and worked for about 5 minutes on a single charge.

After that, I focused more on coding. And even though, I've never made another BEAM robot, it was still a great learning experience and a perfect introduction to the massive world of robotics:)