We thought it would be fun to make an annoying insect that can sit inconspicuously in a room and randomly chirp when its absorbed enough light.

To get there, we needed a oscillator and energy harvester to bring this whimsical idea to life.

We discovered this oscillator circuit on Hackaday and thought it was neat how it leveraged transistors in a unconventional way to make an oscillator. We simulated and built this circuit on protoboard and managed to get it working!

We had some prior experience with the BQ25505 energy harvester chip and since it can turn on at low voltages (0.6V cold start) it should work great for indoor solar.

The initial thinking for solar cells was to use BPW34 photodiodes which was inspired by this photodiode powered BLE chip. This made sense to go on the wings and it was the initial starting point of the project concept as it would look cool and capture plenty of light while the blue shade would add some nice contrast to the design.

After exploring the power we'd get with the photodiodes, it seemed less feasible. As an option, we kept the photodiodes on the main board design but depopulated it and rather went with KXOB25-03X4F-TB to make it more feasible to achieve its ambitious goal.

The original plan for the wings was to have them made from PCBway's 1mm glass material.

We used tracks in a combination of functional and aesthetic ways, playing with the inherent rigidity of pcb design and the organic shapes of the cicada's wings and veins.

--WIP--