Small 5v Solar Panel light sensor and visual solar power indicator.

Hi,

I made this simple demo of a small solar power indicator which outputs pulses to an LED bar. Looks quite retro. I would like to add a sound effect that gives a feeling of the power of the "juice" going into the system and sync it with the pulses. I would like it to be a bit like when the warp coils are maxed out, so it will probably be on polyphonic synth or be playing a recorded sound in a loop.

This is the video and some code: LINK

Can anyone please point me in the right direction?

Many Thanks