what's coming out

Digital Output

Anything that can be turned ON or OFF can be considered as suitable for a digital output signal. Digital Output means output in which there are only two states possible at any one point, either ON (HIGH) or OFF (LOW).

The biggest issue is to ensure that the signal is of sufficient voltage and current to control whatever is at the receiving end of the signal. Bearing in mind that in general a microcontroller will output a 5V, 50mA signal you might need to amplify the signal, or use a relay to ensure sufficient voltage or current.

Voltage range

In digital circuits, the voltage levels corresponding to HIGH and LOW are allowed to fall in some range. For example in TTL logic, anything less than +0.8V is considered LOW and anything greater than +2.0V as HIGH.