I had an idea of simplifying the scr portion of Stan's circuit eliminating the 5 volt voltage regulator. It seems that this part is necessary for the opto-coupler to work in conjunction with the scr. It would involve connecting 2 opto-couplers in series thereby dividing the 12 volts in 1/2 and connecting the scrs in parallel across the line. I'm not an electrician by trade so I'm learning as I go. I am all about keeping it simple though.
I've also read that the scr is based on coupling a pnp and npn transistor in series and wondering if each gate were connected to the led terminal outputs of the optocoupler the transistors would "fire" on completing the circuit.
I don't know if this would be more economical than the 5 volt regulator portion but it might save some space.
Regards,
Andy
