This example shows how to read an analog voltage using the AnalogInput component. The analog signal is then compared to a reference, and if the signal is above the reference, it will turn on an LED. You can see in the following figure how to build this example.
Pin A0 for the Arduino UNO corresponds to pin number 14 for the Firmata. For other boards, the pin numbering may be different. If you have a different board, you can refer to the board capabilities that is printed when the simulation is started to see what pins are mapped to what ports. For the Arduino Lenoardo, A0 is mapped to pin number 18.
Run the simulation and move the potentiometer. You should see that when the position of the shaft is near the middle, the LED changes state.
The AnalogInput component returns a signal between 0 and 1. This value represents the voltage between 0 and the reference voltage. If you prefer to get the signal directly in volts, you need to change the 'MaxValue' property to the reference voltage, but generally it is either 5 V or 3.3 V.