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Lightning Detector.

Discussion in 'General Electronics Discussion' started by cjdelphi, Apr 6, 2012.

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  1. cjdelphi

    cjdelphi

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    Oct 26, 2011
    I came across this Circuit...

    [​IMG]

    I don't really understand the role of the 555, the 555 is set to monostable/1 shot, when current is inducted to the 4ft long copper wire, the voltage/current goes through this circuit, but why would you use the 555 trigger pin for a single pulse? why not simply have the transistor feed straight into the optocoupler?...

    i'm missing something here, I'd love to one day build a lightning detector but knowing me i'd probably want to get as close to a storm as possible a few times just to make sure it works lol... anyway what's the role of the 555 in this circuit?
     
  2. Harald Kapp

    Harald Kapp Moderator Moderator

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  3. cjdelphi

    cjdelphi

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    Oct 26, 2011
    The time is too short for the arduino and not 555?
     
  4. BitHead

    BitHead

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    Mar 2, 2012
    Yes - the 555 looks like it's going to generate a nice, long 1/2 sec.-ish pulse when it's triggered by what could be the very short-duration (sub-microsecond) spiky tip of a lightning strike detect. That's this monostable's job - taking bouncy, spiky, weak transient 'low-going' voltages and turning them into predictably clean-edged, long-duration ones. The monostable is also used a lot for de-bouncing push-button switches being pressed by hesitant, lightly pushing fingers so quick-responding uControllers don't do something twice - or ten - times.
     
  5. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    Also it will essentially integrate pulses over half a second. This means that many pulses generated from the strike get counted only once.

    edit: integrate is the wrong word
     
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