MPR121 - Simple Touch

/*******************************************************************************

 Bare Conductive MPR121 library
 ------------------------------

 SimpleTouch.ino - simple MPR121 touch detection demo with serial output

 Based on code by Jim Lindblom and plenty of inspiration from the Freescale
 Semiconductor datasheets and application notes.

 Bare Conductive code written by Stefan Dzisiewski-Smith and Peter Krige.

 This work is licensed under a MIT license https://opensource.org/licenses/MIT

 Copyright (c) 2016, Bare Conductive

 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
 in the Software without restriction, including without limitation the rights
 to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 copies of the Software, and to permit persons to whom the Software is
 furnished to do so, subject to the following conditions:

 The above copyright notice and this permission notice shall be included in all
 copies or substantial portions of the Software.

 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 SOFTWARE.

*******************************************************************************/

#include <MPR121.h>
#include <Wire.h>

#define numElectrodes 12

void setup()
{
  Serial.begin(115200);
  while(!Serial);  // only needed if you want serial feedback with the
           // Arduino Leonardo or Bare Touch Board

  Wire.begin();

  // 0x5C is the MPR121 I2C address on the Bare Touch Board
  if(!MPR121.begin(0x5A)){
    Serial.println("error setting up MPR121");
    switch(MPR121.getError()){
      case NO_ERROR:
        Serial.println("no error");
        break;
      case ADDRESS_UNKNOWN:
        Serial.println("incorrect address");
        break;
      case READBACK_FAIL:
        Serial.println("readback failure");
        break;
      case OVERCURRENT_FLAG:
        Serial.println("overcurrent on REXT pin");
        break;
      case OUT_OF_RANGE:
        Serial.println("electrode out of range");
        break;
      case NOT_INITED:
        Serial.println("not initialised");
        break;
      default:
        Serial.println("unknown error");
        break;
    }
    while(1);
  }

  // pin 4 is the MPR121 interrupt on the Bare Touch Board
  MPR121.setInterruptPin(4);

  // this is the touch threshold - setting it low makes it more like a proximity trigger
  // default value is 40 for touch
  MPR121.setTouchThreshold(40);

  // this is the release threshold - must ALWAYS be smaller than the touch threshold
  // default value is 20 for touch
  MPR121.setReleaseThreshold(20);

  // initial data update
  MPR121.updateTouchData();
}

void loop()
{
  if(MPR121.touchStatusChanged()){
    MPR121.updateTouchData();
    for(int i=0; i<numElectrodes; i++){
      if(MPR121.isNewTouch(i)){
        Serial.print("electrode ");
        Serial.print(i, DEC);
        Serial.println(" was just touched");
      } else if(MPR121.isNewRelease(i)){
        Serial.print("electrode ");
        Serial.print(i, DEC);
        Serial.println(" was just released");
      }
    }
  }
}