I'm trying to close the contacts of a remote controller (wires are soldered to either side). I have an RPi and I'm yet to buy an optocoupler.
What would I need to get this to work? A Pi outputs 3.3v from a GPIO, but can power a circuit independently at 5v.
I was referencing this thread, but they've included a 9v battery, and I don't know what purpose that serves.
Alternatively, I could use a relay powered by the 5v Pi output which is triggered by the GPIO, but I worry that the contacts on a relay are too resistive to conduct a small switch short. Please advise!
EDIT: Thanks to user Passerby, I now have formula for finding an optocoupler and resistor.
Assuming the Pi outputs 3.3v at 16mA, what's a suitable resistor/optocoupler combination (x & y on schematic)?