How to use potentiometer data from slave to master Arduino? I'm trying to make a game where i can use one Arduino as a controller (the controller is a potentiometer) and the other Arduino sending the signals to the computer. Im trying to figure out communication with two Arduino's so i would like to use two instead of one although using one would be logical and easier. Ive tried looking into I2C but cant seem to figure it out.
Start by reading the potentiometer. Add a Wire request service function and that makes the Slave:

#include &lt;Wire.h&gt;

const uint8_t controllerAddress = 8;
const int controllerPin = A0;
volatile int controllerValue = 0;

void setup() {
  Wire.begin(controllerAddress);
  Wire.onRequest(requestEvent); 
}

void loop() {
  int value = analogRead(controllerPin);
  noInterrupts(); 
    controllerValue = value;  
  interrupts();
}

void requestEvent() {
  Wire.write((const uint8_t*) &amp;controllerValue, sizeof(controllerValue)); 
}


This is minor update of the Arduino Wire Master Reader tutorial. The sketch for the Master is left as an exercise. 

Cheers!