/diy/ - Do It Yourself

I recently built a circuit for a model lighthouse that has a twilight switch and a flasher for a 2 W light bulb. It is powered solely by small AC adapter so power consumption isn't an issue.

I'd like to build a miniature flashing beacon (something like pic related) with a super bright 5 mm white LED, solar panel and some kind of power storage.

I already have a few small solar panels that are rated at 12 V/20 mA. I was thinking to use supercapacitors as power storage for this, but how should I estimate required capacity?

At the moment it seems I would need:
- step-down converter (panel 4..12V --> 2.5V) for charging the capacitor
- step-up converter (2.5 V --> 3.5 V) for driving the LED
- low frequency oscillator/flasher
- comparator to turn the flasher on when the panel voltage drops near zero.

All of these would need to consume as little quiescent current as possible. Any suggestions for ICs/capacitors suitable for this kind of device?