Rolf said:
No, what I want is for the slave to fire when the cameras main flash goes off (the last flash). Then the cameras setup will be unaffected by the slave. It will be used mainly for filling in background when taking pictures in large rooms. Or when taking portraits, as the main flash, when the camera flash will be used in the bounce mode. Used this way, the exposure should be OK.
QUOTE]
Here is what I made:
https://www.pbase.com/sinoline/digital_slave_trigger
**broken link removed**
This output circuit works fine, with my Vivitar 2000, that have a trigger voltage of about 102v. The SCR (MCR100-6) is rated at 400v and the gate resistor is 10 K. But some commercial strobe units have trigger voltages well above 300v and that makes me a little nervous. I don't have a HV variable power supply to test this and I don't have a lot of room on the PCB for an optical isolator circuit.
The IC is a 4011 operated on a 3v supply.
Any ideas?