Hi!
In my work with hacking a treadmill, I have soldered leads onto the buttons on the treadmill. By shorting the leads, the button is pressed, obviously.
When I control this through an arduino I use a 5v relay. But the "clicking-sound" from the relay annoys me, and I was thinking that the same must be possible through the use of transistors. Are there any added risk of connecting the leads between the collector and emitter, and just sending a small amount of current into the base of the transistor to have it "open/push the button".
Or would an opto-isolator work just as well maybe ?