[Adam Y.]

Has anyone experimented with alternative power sources for your robot? Such as hydrogen/direct methanol fuel cells, solar cells, lemons, etc?

Fuel cells are prohibitively expensive at the moment. I read about them in Servo Magazine and the price was really expensive that I could buy a complete robot for the same price as the fuel cell. Solar cells are useful in smaller robots and can directly power a BEAM robot but their ability to work is dependent on the sun and of course the cost is still expensive for larger solar cells. Research is being done with organic materials in order to create new solar cells. Last I knew it was spinach and blackberry (sorry I forgot which berry) that is being used. As for other power sources. I know of one robot whose sole purpose is to eat slugs and use them as a power source. As for batteries you have nickel cadmium, nickel metal hydride,sealed lead acid and lithium ion. These are the only three that I can think that are useful for any type of robotics work. Just match the battery to the job you want it to do.

you could use a model gas engine they use on the gas powered remote control cars to power an alternater. im experimenting with this to provide power to a personal robot ive been planning to build for a while now. im also working on using solar cells to power capacitors on a helium blimp robot im starting to build.

Please someone might want to elaborate because I'm not 100% sure of this but make sure you filter out the output of the alternator or else spikes create d in the alternator might blow any electronics you have. As for powering a blimp using solar cells and capacitors, I would recommend using a BEAM engine particularly the one I'm linking to. It uses a few capacitors and a few other components to power a motor.BEAM