We were thinking that we might want to add a solar cell to the room motes so the batteries wouldn’t have to be changed.
Joe got a 2.75″x4.25″ PowerFilm MPT6-75 solar cell. In the lab lighting, we got .23 mA at a voltage sufficient to recharge the battery. When we put it directly in front of a 175W grow light we got about 25mA.
Typically a mote consumes about 25mA (at 3.3V) when it is on and broadcasting and a few microA when it is sleeping. The utility of adding the solar panel depends on the duty cycle, the ratio of time spent broadcasting and sleeping. If the duty cycle is < 1% the solar panel would just about make up for the power consumed by the mote. If you account for the time when the inside lights are out, the duty cycle should be < 0.5%.
