This Arduino code basically based on serial communication concept. When the microcontroller receives a serial data, then it will perform a specific task pre-programmed by the user. For example when ...

Download the codes here Arduino simple shield potentiometer code: Arduino shield rc car: Arduino nano module L298P code: ...

A perl script running on the iPhone will then send the command to the Arduino. When it receives the start command, the Arduino will ground the wire to the remote start and fire up the car.

The Arduino code tells us that the valves will be opened as long as the remote up/down channel is above/under given values.