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Re: Working: A fiber optic trigger lead for (DR)SSTC`s

Original poster: Steve Conner <steve@xxxxxxxxxxxx>

Hi Finn, all,

That's great that you got a cheap fibre optic link to work. And 100 feet is an amazing range, almost a safe distance for Ward's next DRSSTC ;)

If you're building more of them, you can wire my PLL driver to accept an active low trigger input and do away with the 555, which might make your dongle a bit less cramped. On the 9-way D input socket, instead of grounding pin 3 and driving the signal into pin 2: Connect pin 2 to the +15v supply (on pin 5) and drive the signal into pin 3.

Steve Conner

I can now verify, that it is possible and easy to make a fiber optic trigger connection to any SSTC. I just completed one for myself, starting out with a transmitter driven from a 555 trigger generator: The transmitting LED is driven btwn pin3 and ground of the 555, with a 680ohm resistor to set the current.
Nothing fancy, the transmitter is at the top of the box. Bypasscaps below board.
Closed, the box looks like this:
The receiver is active low, so I had to reverse it. At first I used a comparator, LM311 and it worked well on the breadboard, but I thought it better to have some hysteresis, the more tha merrier. Since I could not find any schmitt triggers in an 8DIP housing, I wired the 555 as a schmitt:

I wanted the whole circuitry to fit into a 9pin Dsub shell, so I needed the 8pin package. 15V is already available in the socket, Since I use Stephen Conners PLL drivers, still not a lot of space left:
It all plays very well, here is a short video of one of my DRSSTC`s driven by the combo on each end of 100 feet of fiber:

You guys remember how good it felt to make your first working electronic project? Then you know how I feel now. I feel pretty damn good!

Cheers, Finn Hammer