Arduino/build/shared/examples/10.Mouse/JoystickMouseControl/JoystickMouseControl.ino

/*
  JoystickMouseControl
 
 Controls the mouse from a joystick on an Arduino Leonardo.
 Uses a pushbutton to turn on and off mouse control.
 
 Hardware:
 * 2-axis joystick connected to pins A1 and A2
 * pushbutton connected to pin D6
 
 The mouse movement is always relative. This sketch reads 
 two analog inputs that range from 0 to 1023 (or less on either end)
 and translates them into ranges of -60 to 60. 
 The sketch assumes that the joystick resting values are around the 
 middle of the range, but that they vary within a threshold.
 
 WARNING:  When you use the Mouse.move() command, the Arduino takes
 over your mouse!  Make sure you have control before you use the command.
 This sketch includes a pushbutton to toggle the mouse control state, so
 you can turn on and off mouse control.
 
 created 15 Sept 2011
 updated 16 Jan 2012
 by Tom Igoe
 
 this code is in the public domain
 
 */

// set pin numbers for switch, joystick axes, and LED:
const int switchPin = 6;      // switch to turn on and off mouse control
const int xAxis = A1;         // joystick X axis  
const int yAxis = A2;         // joystick Y axis
const int ledPin = 5;         // Mouse control LED 

// parameters for reading the joystick:
int range = 12;               // output range of X or Y movement
int responseDelay = 2;       // response delay of the mouse, in ms
int threshold = range/4;      // resting threshold
int center = range/2;         // resting position value
int minima[] = { 
  1023, 1023};                // actual analogRead minima for {x, y}
int maxima[] = {
  0,0};                       // actual analogRead maxima for {x, y}
int axis[] = {
  xAxis, yAxis};              // pin numbers for {x, y}
int mouseReading[2];          // final mouse readings for {x, y}


boolean mouseIsActive = false;    // whether or not to control the mouse
int lastSwitchState = LOW;        // previous switch state

void setup() {
  pinMode(switchPin, INPUT);       // the switch pin
  pinMode(ledPin, OUTPUT);         // the LED pin  
}

void loop() {
  // read the switch:
  int switchState = digitalRead(switchPin);
  // if it's changed and it's high, toggle the mouse state:
  if (switchState != lastSwitchState) {
    if (switchState == HIGH) {
      mouseIsActive = !mouseIsActive;
  // turn on LED to indicate mouse state:
  digitalWrite(ledPin, mouseIsActive);
    } 
  }
  // save switch state for next comparison:
  lastSwitchState = switchState;

// read and scale the two axes:
  int xReading = readAxis(0);
  int yReading = readAxis(1);

// if the mouse control state is active, move the mouse:
  if (mouseIsActive) {
    Mouse.move(xReading, yReading, 0);
  }  
  delay(responseDelay);
}

/*
  reads an axis (0 or 1 for x or y) and scales the 
  analog input range to a range from 0 to <range>
*/

int readAxis(int axisNumber) {
  int distance = 0;    // distance from center of the output range
  
  // read the analog input:
  int reading = analogRead(axis[axisNumber]);

// of the current reading exceeds the max or min for this axis,
// reset the max or min:
  if (reading < minima[axisNumber]) {
    minima[axisNumber] = reading;
  }
  if (reading > maxima[axisNumber]) {
    maxima[axisNumber] = reading;
  }
  
  // map the reading from the analog input range to the output range:
  reading = map(reading, minima[axisNumber], maxima[axisNumber], 0, range);
 
 // if the output reading is outside from the
 // rest position threshold,  use it:
  if (abs(reading - center) > threshold) {
    distance = (reading - center);
  } 
  
  // the Y axis needs to be inverted in order to 
  // map the movemment correctly:
  if (axisNumber == 1) {
    distance = -distance;
  }
  
  // return the distance for this axis:
  return distance;
}