Photographic Flash Slave for high voltage trigger flash units like the Stroboflash.
Here is a 21st century technology -- ultra sensitive slave -- you can easily build and use with your Stroboflash units. It far exceeds the capabilities of the vintage vacuum tube slaves and even some new "peanut" slaves. I designed this slave to light buildings out of doors at night. For all you spelunkers that tool around in caves for jollies it would work great there too. In testing I was able to trigger the slave from over 400 feet away using 1/4 power. As long as the phototransistor can "see" the flash or a reflection of the flash it will trigger. Normal room lighting does not affect it either. I suspect it will trigger at much further distances but I ran in to a fence and could go no further. This slave will not work with digital cameras that fire a pre-flash prior to the main flash. I use this with a Nikon D70 digital camera set to (M) manual mode.
Stroboslave does not work out of doors in sunlight. It is intended for indoor or night time use only. Bright fluorescent lights are OK.
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Stroboflash Al
Finished unit:
I stuck a piece of foam weather
stripping to the back of the PC board for insulation and then used a rubber band
to attach the battery.
This pulse detected by the infrared sensitive phototransistor is amplified by the 2N2222 transistor. This amplified pulse triggers the gate of a 400v sensitive gate Triac. The Triac acts as a switch triggering the Stroboflash head that it is plugged in to.
Schematic:
Printed circuit board artwork:
Bottom on left, Top on right reversed for laser printing to PC board.
Parts List:
Parts are available from Mouser Electronics www.mouser.com
| Phototransistor | OPTEK #OP598B |
| Triac | LittelFuse L6004L3 or any 400v sensitive gate triac. |
| Any 2N2222 transistor | |
| Resistors are 1/8 watt 10% values are not real critical +- 10% is OK |