LED Flasher - not so simple?!

Discussion in 'The Projects Forum' started by SystemsGuy, Jun 30, 2012.

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  1. SystemsGuy

    Thread Starter New Member

    Jun 29, 2012
    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?
  2. Wendy


    Mar 24, 2008
    The owners of All About Circuits has elected not to host discussions of automotive electrical system modifications/enhancements due to safety concerns, the potential of legal ramifications and the possible circumvention of vehicle regulations at the state and federal level.

    This thread is against the AAC forum rules, Chapter 6, as seen here:

    This can be found in our Terms of Service (ToS)

    Automotive modifications of any kind are strictly forbidden. Therefore, this thread will be closed.

    Please try to understand the reasons behind this action, and feel free to browse and use the forums.

    You might find answers to your questions in one of these forums:


    Another good forum that shares many of the same membership is http://www.electro-tech-online.com/ . Good luck.
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