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How to modify a camera flash circuit for external trigger — Parallax Forums

How to modify a camera flash circuit for external trigger

ArchiverArchiver Posts: 46,084
edited 2002-08-01 03:25 in General Discussion
Hello,

I have a xenon flash circuit from one of those disposable cameras. The
camera has two switches. One to turn the charge circuit on, and another to
initiate the flash when pressed. I want to modify the circuit to detect
dusk using a CDS cell and come on, detect dawn an go off. I would like
some kind of timing circuit, probably utilizing a 555 chip with a counter
that can be set to say flash 2, 3, or 4 times a minute.

What I think I have in mind is a 555 circuit with a 50% duty cycle and a
decade counter chip with a reset pin. Once the count has reached a certain
number, it triggers the flash and resets the decade counter. I have also
thought about a cheep micro to do these functions along with some type of
pot command to read the light intensity.

Does anyone have any ideas on how to flash the strobe. I mean, what
component could handle the voltage/current going through it?

Brian G.

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2002-08-01 03:25
    A while back, Nuts & Volts had an article on hacking the Kodak disposable
    camera circuit for a shocker and a strobe -- check their back issues.

    The tube itself is charged to about 300 volts DC -- this is across the
    terminals on each end. It is triggered by a 3-4,000 volt pulse applied to
    the wire or foil around the middle of the tube.

    Original Message

    > I have a xenon flash circuit from one of those disposable cameras. The
    > camera has two switches. One to turn the charge circuit on, and another
    to
    > initiate the flash when pressed. I want to modify the circuit to detect
    > dusk using a CDS cell and come on, detect dawn an go off. I would like
    > some kind of timing circuit, probably utilizing a 555 chip with a counter
    > that can be set to say flash 2, 3, or 4 times a minute.
    >
    > What I think I have in mind is a 555 circuit with a 50% duty cycle and a
    > decade counter chip with a reset pin. Once the count has reached a
    certain
    > number, it triggers the flash and resets the decade counter. I have also
    > thought about a cheep micro to do these functions along with some type of
    > pot command to read the light intensity.
    >
    > Does anyone have any ideas on how to flash the strobe. I mean, what
    > component could handle the voltage/current going through it?
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