P3D Two useful tips (kinda long)

[Robert Cruickshank <robcruic@xxxxxxxxxxxx>]

A couple of things that may be useful: 
First, I found that the stuff they sell to clean skis (it's called
fiberlene, not sure if that's a trademark) makes a great lint-free surface
for slide mounting. (I used to spread out tracing paper, but it was rather
wasteful) Now when done with a piece of it, it goes downstairs to the
waxing bench, and nothing is wasted. Also, it looks and feels a lot like
Tough Spun, so it might be useful as diffusing material (although it DOES
burn rather nicely, so I would only use it for strobes.) A roll of it
set me back $16 CDN (about 38 cents US...)
Second, speaking of strobes, I found a bin of flashes "recycled" from
"disposable" cameras (which IMHO are a pox on the face of the earth) at a
local surplus store, and bought a few for $1.50CDN each to play with. 
By adding a phototransistor, (75 cents) and a triac ($1.50) I made little
slave that seems to work quite well. I still have a few details to work
out on it, but it looks promising. I'm sure if you can't buy these things,
a local photo store could give you some. (the place where I take my slide
film gives me as many disposable camera shells as I want- good for
reloading or sawing up to make horrible stereo cameras..) 
I'll maybe do a web page with pictures on how to make these slaves, but
in a nutshell: connect the main leads of the triac where the shutter
contacts connect (some have wires, others have spring contacts.) Connect
the collector of the phototransistor to the positive battery terminal, and
the emitter to the gate of the triac. The triac should be at least 400v, 1
amp. I think there should be a small resistor in between the transistor
and the triac, but I haven't figured out the value yet, and it hasn't
blown up yet..also there should be a capacitor in there somewhere, so the
triac only fires on an edge, but so far I haven't been able to make it
false trigger, and it fires from more than 20 feet away.
Oh and BE CAREFUL. Just about everything in those little flashes sits at
about 200 volts. If the above doesn't make total sense, you might not want
to fool around without more detailed instructions.
Have fun, and if anyone comes up with any new discoveries, let me know.
I've got a bag of various phototransistors and triacs, so I can do some
tweaking of the circuit this weekend.
    


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Rob Cruickshank                    robcruic@xxxxxxxxxxxx  
www.interlog.com/~robcruic
                



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