So I've played with a few flasher circuits over the years, and have lately found myself with some free time, so am trying to revive an old pet project.

I saw a pretty cool 3rd brake light flasher the other day with an interesting twist - it had the concept of a "delay" built into it. Basically, it could be programmed with basic flash rates and sequences - pretty straightforward stuff I've done before.

This one, however, allow you to also build in a "delay" such that if you hit the brakes again within a time period, it would not flash the light again.

Pretty straight forward, until I start thinking about it. The device is only powered when the brakes are on - so how does it "know" that 15, 30 or 45 seconds have passed since the last time it had power?

I though probably using a capacitor, and detecting discharge level, or using a big enough capacitor to keep the circuit powered for the desired max delay?

Was trying to come up with a more elegant solution - I can do all the above with a Amtel AVR, but really didn't want to have a RTC or battery in the circuit if I could avoid it.

I'm a digital sort of guy, so limited experience with anything that does not have power! ;-)

Any clever ideas or thoughts on how this could be accomplished?

 

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