Here is a quick BEAM style robot. It uses a Miller Solar Engine and a 4700 uf cap to drive a 3v buzzer. It is quite active in direct sunlight. Much louder than I thought it would turn out. I was going for more of a chirping effect but in full sunlight it produces a constant buzz. Cool albeit a bit annoying. We will be moving out of the house we are in soon. It would be kind of fun to find a good hiding spot and drive the new owner crazy trying to figure it out. Although it was a quick and easy build I am kind of proud of the stark simplicity and effectiveness. I guess that is what BEAM is all about.