Analog - arthurbenemann/ardupilot GitHub Wiki
!ArduPilotMega has two spare ports for additional analog sensors. You can find them on the IMU shield here.
http://ardupilot-mega.googlecode.com/svn/ArduPilotMegaImages/expansion.png
The data can be read on Arduino's Analog 6 and Analog7. Here's a sample sketch that will show you how:
int val1 = 0; // variables to store the value read
int val2 = 0;
void setup()
{
Serial.begin(9600); // setup serial
}
void loop()
{
val1 = analogRead(6); // read the input pin
Serial.print("Analog 6: ");
Serial.print(val1); // debug value
val2 = analogRead(7); // read the input pin
Serial.print(" Analog 7: ");
Serial.println(val2); // debug value
}