See my previous blog.
The circuit runs off a photovoltaic cell that puts out approximately 3.85 volts during a sunny day. The chirps put a small load during the noises and the voltage changes very little, maybe .03 volt. I think the photovoltaic cell could drive a few LEDs without any problem.
I thought it might look nice if the circuit blinked some LEDs. The blinking would not necessarily have to blink in unison with the chirps.
The circuit works only during bright sunlight. I think it would be a good idea to connect a pair of supercapacitors in series to the photovoltaic cell and charge them in the daytime so it will annoy everyone with the chirps for hours after the sun sets. :-O
I think I could use a few milliamps from the PV cell to power a 1 transistor FM transmitter. This would send the chirps a few tens of feet to any FM radio. The frequency would be on the low end of the band from 88 to 92 MHz.
