A while back I made dozens of robots which were in large part inspired by BEAM Robotics. For those unfamiliar, BEAM is basically a special method of robot building with an emphasis on biology, electronics, aesthetics, and mechanics (hence the acronym BEAM). One thing that sets BEAM apart from other approaches to robotics is its insistence on using radiant energy (predominantly solar power) and its tendency towards reuse and minimalism. While I heavily borrowed from the BEAM ethos and aesthetics, the robots that I built were not quite the same (they were all battery powered for starters).
Since BEAM robotics was such a large source of inspiration, I always wanted to try my hand at building a solar robot. However, rather than simply building another BEAM robot, I decided to incorporate solar into my own style of robot building. Instead of having it be powered entirely off the sun, I decided to incorporate rechargeable batteries. This means that at any given time the motors can be running off either the batteries or solar panel, depending on which can provide the most power. The solar panel is also recharging the batteries when the sun hits it. This allows the bot to run off of the sun, but not be entirely reliant upon it to move.
I think my approach merges the two styles nicely, and is a fun and simple experiment in robot building.
Step 1: Materials
(x1) Solar panel (Radioshack #277-052)
(x2) Standard servos (Radioshack #273-766)
(x3) 1N5817 schottky diodes - NTE578 equivalent (Radioshack #55052253)
(x1) 9V battery snap (Radioshack #270-324)
(x8) AA rechargeable batteries (Radioshack #23-760)
(x1) 8 x AA Battery holder (Radioshack #270-387)
(x12) Wire-tie mounts (Radioshack #278-441)
(x1) Ruler (12" - 18")
(x2) Wall mount adhesive hooks
(x1) Misc. zip ties
(x1) Shrink tube