hey guys
so im building an instrument with capacitive touch sensors for keys.
i have the amazing MPR121 capacitance breakout board and it works wonderfully.
however, it only enables me to get input from 12 electrodes. i need 13 for a full octave (c to c').
i downloaded capsense, and tried to implement the code into my pre-existing MPR sketch, and well - i do get input from the capsense button on the arduino - but the latency is around 1 second!
if you could help me out, and tell me why my code slows down like that - i would be a very happy person.
here is my messy code - capsense is //commented. MPR121 code is taken from bildr.org
::
//#include <CapSense.h>
#include "mpr121.h"
#include <Wire.h>
#include <SimpleMessageSystem.h>
//CapSense cs_19_15 = CapSense(2,3);
int irqpin = 12; // Digital 12
boolean touchStates[12]; //to keep track of the previous touch states
void setup(){
pinMode(irqpin, INPUT);
digitalWrite(irqpin, HIGH); //enable pullup resistor
Serial.begin(9600);
Wire.begin();
mpr121_setup();
}
void loop(){
//
// long tot = cs_19_15.capSense(30);
// Serial.print(tot);
// Serial.println("\t");
//
// if(tot < 5000){
// digitalWrite(13, LOW);
// }
// if(tot > 5000){
//
// digitalWrite(13, HIGH);
// }
// delay(10);
//}
readTouchInputs();
{
if (messageBuild() > 0) { // Checks to see if the message is complete and erases any previous messages
switch (messageGetChar()) { // Gets the first word as a character
case 'r': // Read pins (analog or digital)
readpins(); // Call the readpins function
break; // Break from the switch
case 'w': // Write pin
writepin(); // Call the writepin function
}
}
}
}
void readTouchInputs(){
if(!checkInterrupt()){
//read the touch state from the MPR121
Wire.requestFrom(0x5A,2);
byte LSB = Wire.receive();
byte MSB = Wire.receive();
uint16_t touched = ((MSB << 8) | LSB); //16bits that make up the touch states
for (int i=0; i < 12; i++){ // Check what electrodes were pressed
if(touched & (1<<i)){
if(touchStates[i] == 0){
//pin i was just touched
Serial.print("pin ");
Serial.print(i);
Serial.println(" was just touched");
digitalWrite(i+2, HIGH);
digitalWrite(13, HIGH);
}else if(touchStates[i] == 1){
//pin i is still being touched
}
touchStates[i] = 1;
}else{
if(touchStates[i] == 1){
Serial.print("pin ");
Serial.print(i);
Serial.println(" is no longer being touched");
digitalWrite(i+2, LOW);
digitalWrite(13, LOW);
//pin i is no longer being touched
}
touchStates[i] = 0;
}
}
}
}
void mpr121_setup(void){
// Section A - Controls filtering when data is > baseline.
set_register(0x5A, MHD_R, 0x01);
set_register(0x5A, NHD_R, 0x01);
set_register(0x5A, NCL_R, 0x00);
set_register(0x5A, FDL_R, 0x00);
// Section B - Controls filtering when data is < baseline.
set_register(0x5A, MHD_F, 0x01);
set_register(0x5A, NHD_F, 0x01);
set_register(0x5A, NCL_F, 0xFF);
set_register(0x5A, FDL_F, 0x02);
// 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 Filter Configuration
// Set ESI2
set_register(0x5A, FIL_CFG, 0x04);
// Section E
// Electrode Configuration
// Set ELE_CFG to 0x00 to return to standby mode
set_register(0x5A, ELE_CFG, 0x0C); // Enables all 12 Electrodes
// Section F
// Enable Auto Config and auto Reconfig
/*set_register(0x5A, ATO_CFG0, 0x0B);
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
}
boolean checkInterrupt(void){
return digitalRead(irqpin);
}
void set_register(int address, unsigned char r, unsigned char v){
Wire.beginTransmission(address);
Wire.send(r);
Wire.send(v);
Wire.endTransmission();
}
//commence max communication!
void readpins(){ // Read pins (analog or digital)
switch (messageGetChar()) { // Gets the next word as a character
case 'd': // READ digital pins
messageSendChar('d'); // Echo what is being read
for (char i=2;i<14;i++) {
messageSendInt(digitalRead(i)); // Read pins 2 to 13
}
messageEnd(); // Terminate the message being sent
break; // Break from the switch
case 'a': // READ analog pins
messageSendChar('a'); // Echo what is being read
for (char i=0;i<6;i++) {
messageSendInt(analogRead(i)); // Read pins 0 to 5
}
messageEnd(); // Terminate the message being sent
}
}
void writepin() { // Write pin
int pin;
int state;
switch (messageGetChar()) { // Gets the next word as a character
case 'a' : // WRITE an analog pin
pin = messageGetInt(); // Gets the next word as an integer
state = messageGetInt(); // Gets the next word as an integer
pinMode(pin, OUTPUT); //Sets the state of the pin to an output
analogWrite(pin, state); //Sets the PWM of the pin
break; // Break from the switch
// WRITE a digital pin
case 'd' :
pin = messageGetInt(); // Gets the next word as an integer
state = messageGetInt(); // Gets the next word as an integer
pinMode(pin,OUTPUT); //Sets the state of the pin to an output
digitalWrite(pin,state); //Sets the state of the pin HIGH (1) or LOW (0)
}
}