I've built a sensor (an infrared barrier) for replacing an old one, and it's almost done. But I have to interface it with a input/output board for PC (which is legacy too) and have almost no documentation. The old barrier had a relay and was connected to the board with that. But I don't want to use a mechanical part here so I thought I could replace the relay with a simple transistor working like a switch. I have to measure it yet, but I don think the board works with voltage above 12V (maximum).
What do you think about it?
What do you think about it?