I love this transformation of a Solarbotics Photopopper into a drawbot, simply by attaching an alligator clip to the back of the bot and clipping on a pen. The site is in Spanish. Here’s a translation of the page, though the image pretty much speaks for itself.
Photopopper Photovore 5.0
Our Price: $45.00
The Photopopper Photovore utilizes very small high-efficiency motors in combination with elegant circuitry to make a very active solar-powered robot capable of covering a meter (3.3 feet) in under a minute!