I'm using an Arduino Due board with an optocoupler 4N25 to simulate a button pressed. I have to open and close a circuit that drive an actuator. In that circuit, when connected, with the tester I'm measuring 6V.
I connect the anode to the pin 12 and the cathode in series with a 150-ohm resistor to ground, and Collector and Emitter from optocopupler to the circuit (and a normal Blink example with the pin 12).
When optocoupler is fired on and off respectively with a tester I measure 0V and 1.7V in the arduino part, and 4V and 6V.
This is not enough and the actuator is always run. I'd like to read 0-6V instad of 4V-6V. Does this depends on how much current goes to the anode/cathode of the optocoupler? Do I have to change the resistor in the arduino part? Any kind of advice? What can I do?
I don't want to use relay because I have read that in respect to a relay they are faster, smaller, longer-lived and quieter.