Re: Triggering multiple flashes to "paint with light"

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Article #11879

#11879

From: Gil Nardo
Date: Tue, 06 Oct 1992 21:56

40 lines
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fontana@dogwood.cis.ohio-state.edu (Mark Fontana) writes:
[discussion about triggering photo-flash from main flash deleted]
> I'm looking for advice on how to wire these up.  I figure I can
> just use an RC circuit on each one to get the desired delay.  The two
> main problems are:
> 
>      1) detecting the main flash, which may be very faint, depending
>         on the placement of each auxilliary unit.  If anyone can think
>         of an easier way using sound, say from a cap gun or something,
>         I'm open to suggestions.

The choices for light sensors are photo-resistors, solar cells, and
photo-transistors.  Use any of these in conjunction with circuits
containing a relay and you you have yourself a light-sensitive switch.  
Here is an example from a Radio Shack mini notebook (cat no. 276-5012):

                +9
                 |
    +------------+
    |            | 
    |            | 
 ~--Q1           |
    |            |
    +------------Q2-----+
    |                   |
    R1                Relay
    |                   |
    +-------------------+
    |
    GND

Q1 = Photo transistor where ~ is light input
Q2 = 2N2222
R1 = 100K pot (adjust for sensitivity)
Relay = 500 Ohm, 6-9V
-- 
Gil Nardo                  | mcs@wet.com
Migrant Computing Services | (415)664-1032
1032 Irving Street, #435   |-----------------
San Francisco, 94122       | Supernova = *!

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From: mcs@wet.UUCP (Gil Nardo)
Newsgroups: sci.electronics
Subject: Re: Triggering multiple flashes to "paint with light"
Message-ID: <4339@wet.UUCP>
Date: 6 Oct 92 21:56:55 GMT
References: <1992Oct6.151125.15989@cis.ohio-state.edu>
Distribution: usa
Organization: Wetware Diversions, San Francisco
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