Hi everyone,
I've used Arduino and Max for the last two years for sound installations and other audio based work. However, these have usually been standalone in either program, and this is the first time I've used serial communication. I'm hoping someone could advise me on the Arduino end, as I'm sure it's there that something is going wrong.
I have posted previously on this topic but have since made some progress. I have 12 sensors coming from an MPR121 through an Arduino Mega. In Arduino's Serial Monitor I can clearly see which sensors (0-11) are being touched. Code below.
However, in Max, although I can see that a sensor is being touched, I cannot determine which sensor is being touched. I have attached a screenshot of this (comes up Data: 0)
I'm fairly certain that there is not a problem from the Max side, and that this is a problem in the Arduino sketch, i.e, my coding's not up to scratch!
If anyone can enlighten me on this please do. Thanks in advances for your brain power and time.
J.
/*!
* @filename capactivite_prox_sensor_mpr121.ino
* @author Julio Terra
* @date May 22, 2013
* @version 1.0.1
*
* Please check-out the read-me for details about how to hook-up the Arduino and the MPR121
* breakout boards.
*
*/
#include "mpr121.h"
#include <Wire.h>
#define SENSORS 13
#define TOU_THRESH 0x1F
#define REL_THRESH 0x1A
#define PROX_THRESH 0x3f
#define PREL_THRESH 0x3c
// variables: capacitive sensing
bool touchStates[SENSORS]; // holds the current touch/prox state of all sensors
bool activeSensors[SENSORS] = {1,1,1,1,1,1,1,1,1,1,1,1,1}; // holds which sensors are active (0=inactive, 1=active)
bool newData = false; // flag that is set to true when new data is available from capacitive sensor
int irqpin = 2; // pin that connects to notifies when data is available from capacitive sensor
void setup(){
// attach interrupt to pin - interrupt 1 is on pin 2 of the arduino (confusing I know)
attachInterrupt(0, dataAvailable, FALLING);
// set-up the Serial and I2C/Wire connections
Serial.begin(9600);
Wire.begin();
// set the registers on the capacitive sensing IC
setupCapacitiveRegisters();
}
void loop(){
readCapacitiveSensor();
}
/**
* dataAvailable Callback method that runs whenever new data becomes available on from the capacitive sensor.
* This method was attached to the interrupt on pin 2, and is called whenever that pins goes low.
*/
void dataAvailable() {
newData = true;
}
/**
* readCapacitiveSensor Reads the capacitive sensor values from the MP121 IC. It makes a request to
* the sensor chip via the I2C/Wire connection, and then parses the sensor values which are stored on
* the first 13 bits of the 16-bit response msg.
*/
void readCapacitiveSensor(){
if(newData){
//read the touch state from the MPR121
Wire.requestFrom(0x5A,2);
byte tLSB = Wire.read();
byte tMSB = Wire.read();
uint16_t touched = ((tMSB << 8) | tLSB); //16bits that make up the touch states
for (int i = 0; i < SENSORS; i++){ // Check what electrodes were pressed
if (activeSensors[i] == 0) continue;
char sensor_id [] = {'\0','\0','\0'};
switch (i) {
case 12:
sensor_id[0] = 'P';
break;
default:
if (i < 10) {
sensor_id[0] = char( i+48 );
}
else if (i < 12) {
sensor_id[0] = char('1');
sensor_id[1] = char( ( i % 10 ) + 48 );
}
}
if (sensor_id != '\0') {
// read the humidity level
// if current sensor was touched (check appropriate bit on touched var)
if(touched & (1<<i)){
// if current pin was not previously touched send a serial message
if(touchStates[i] == 0){
Serial.print(sensor_id);
Serial.print(":");
Serial.println("touched");
}
touchStates[i] = 1;
} else {
// if current pin was just touched send serial message
if(touchStates[i] == 1){
Serial.print(sensor_id);
Serial.print(":");
Serial.println("not touched");
}
touchStates[i] = 0;
}
}
}
newData = false;
}
}
/**
* setupCapacitiveRegisters Updates all of configurations on the MP121 capacitive sensing IC. This includes
* setting levels for all filters, touch and proximity sensing activation and release thresholds, debounce,
* and auto-configurations options. At the end it activates all of the electrodes.
*/
void setupCapacitiveRegisters(){
set_register(0x5A, ELE_CFG, 0x00);
// Section A - filtering when data is > baseline.
// touch sensing
set_register(0x5A, MHD_R, 0x01);
set_register(0x5A, NHD_R, 0x01);
set_register(0x5A, NCL_R, 0x00);
set_register(0x5A, FDL_R, 0x00);
// prox sensing
set_register(0x5A, PROX_MHDR, 0xFF);
set_register(0x5A, PROX_NHDAR, 0xFF);
set_register(0x5A, PROX_NCLR, 0x00);
set_register(0x5A, PROX_FDLR, 0x00);
// Section B - filtering when data is < baseline.
// touch sensing
set_register(0x5A, MHD_F, 0x01);
set_register(0x5A, NHD_F, 0x01);
set_register(0x5A, NCL_F, 0xFF);
set_register(0x5A, FDL_F, 0x02);
// prox sensing
set_register(0x5A, PROX_MHDF, 0x01);
set_register(0x5A, PROX_NHDAF, 0x01);
set_register(0x5A, PROX_NCLF, 0xFF);
set_register(0x5A, PROX_NDLF, 0xFF);
// Section C - Sets touch and release thresholds for each electrode
set_register(0x5A, ELE0_T, TOU_THRESH);
set_register(0x5A, ELE0_R, REL_THRESH);
set_register(0x5A, ELE1_T, TOU_THRESH);
set_register(0x5A, ELE1_R, REL_THRESH);
set_register(0x5A, ELE2_T, TOU_THRESH);
set_register(0x5A, ELE2_R, REL_THRESH);
set_register(0x5A, ELE3_T, TOU_THRESH);
set_register(0x5A, ELE3_R, REL_THRESH);
set_register(0x5A, ELE4_T, TOU_THRESH);
set_register(0x5A, ELE4_R, REL_THRESH);
set_register(0x5A, ELE5_T, TOU_THRESH);
set_register(0x5A, ELE5_R, REL_THRESH);
set_register(0x5A, ELE6_T, TOU_THRESH);
set_register(0x5A, ELE6_R, REL_THRESH);
set_register(0x5A, ELE7_T, TOU_THRESH);
set_register(0x5A, ELE7_R, REL_THRESH);
set_register(0x5A, ELE8_T, TOU_THRESH);
set_register(0x5A, ELE8_R, REL_THRESH);
set_register(0x5A, ELE9_T, TOU_THRESH);
set_register(0x5A, ELE9_R, REL_THRESH);
set_register(0x5A, ELE10_T, TOU_THRESH);
set_register(0x5A, ELE10_R, REL_THRESH);
set_register(0x5A, ELE11_T, TOU_THRESH);
set_register(0x5A, ELE11_R, REL_THRESH);
// Section D - Set the touch filter Configuration
set_register(0x5A, FIL_CFG, 0x04);
// Section E - Set proximity sensing threshold and release
set_register(0x5A, PRO_T, PROX_THRESH); // sets the proximity sensor threshold
set_register(0x5A, PRO_R, PREL_THRESH); // sets the proximity sensor release
// Section F - Set proximity sensor debounce
set_register(0x59, PROX_DEB, 0x50); // PROX debounce
// Section G - Set Auto Config and Auto Reconfig for prox sensing
set_register(0x5A, ATO_CFGU, 0xC9); // USL = (Vdd-0.7)/vdd*256 = 0xC9 @3.3V
set_register(0x5A, ATO_CFGL, 0x82); // LSL = 0.65*USL = 0x82 @3.3V
set_register(0x5A, ATO_CFGT, 0xB5); // Target = 0.9*USL = 0xB5 @3.3V
set_register(0x5A, ATO_CFG0, 0x0B);
// Section H - Start listening to all electrodes and the proximity sensor
set_register(0x5A, ELE_CFG, 0x3C);
}
/**
* set_register Sets a register on a device connected via I2C. It accepts the device's address,
* register location, and the register value.
* @param address The address of the I2C device
* @param r The register's address on the I2C device
* @param v The new value for the register
*/
void set_register(int address, unsigned char r, unsigned char v){
Wire.beginTransmission(address);
Wire.write(r);
Wire.write(v);
Wire.endTransmission();
}
