This unique circuit has been tried with all three of my cameras and two others and works perfectly. It ignores all pre-flashes and only triggers on the last (main) flash.
No adjustments are needed. It will be tested with more cameras as they become available.
The current drawn is just 2.2mA at 3v. (about 4.2mA at 6v)The AA batteries were only used for making and testing the prototype. The finished unit will use a coin cell. The unit will handle trigger voltages up to 400v. Which I think will handle most commercial strobe units.
The range with 3v is about 25', I am going to work on that. That was much better when I used a 6v battery. There is now a ON / OFF sw. But the blinking LED (shown only in the picture) has been removed, drew to much current.
The hot-shoe was from an old camera I got in a junk store for $ 1.00.
This design is now outdated because of this: http://www.pbase.com/sinoline/pic_slave_flash
Digital slave flash trigger
This unique circuit has been tried with all three of my cameras and two others and works perfectly.