|
Re: Use positive signal to trigger digital input
You short the signal wire of the switch to ground through a resistor.
When the switch is open, the signal is shorted to ground, and thus reads 0 volts.
When the switch is closed, power flows from the switch to the roboRio and it sees +5 volts.
The value of the resistor you use is dependent upon your switch. If you can't find anything in the spec sheet of the switch, try starting with 10K ohms, and work down from there.
I think the RoboRio pulls the signal line to +5 through an internal resistor, and that is what you need to overcome.
|