Hello,
im currently working on a project, which uses the capacitive sensor "MPR121" and the Bluetooth Module HC-05 on the Arduino Pro Mini.
The MPR121 itself is working, but as soon as I add the HC-05 Bluetooth module to the Arduino, the MPR constantly outputs random data, without me touching the pins of the MPR.
The problem occurs either when the HC-05 is only connected to the same power source and not used at all to transfer data or when the HC-05 is connected to a seperate power source and connected to transfer data.
I am using 3.3V.
The code I'm using at this moment for testing only the MPR121 functionality is the example from the MPR121 library "Adafruit", which isn't even featuring the bluetooth module:
#include <Wire.h>
#include "Adafruit_MPR121.h"
// You can have up to 4 on one i2c bus but one is enough for testing!
Adafruit_MPR121 cap = Adafruit_MPR121();
// Keeps track of the last pins touched
// so we know when buttons are 'released'
uint16_t lasttouched = 0;
uint16_t currtouched = 0;
void setup() {
while (!Serial); // needed to keep leonardo/micro from starting too fast!
Serial.begin(9600);
Serial.println("Adafruit MPR121 Capacitive Touch sensor test");
// Default address is 0x5A, if tied to 3.3V its 0x5B
// If tied to SDA its 0x5C and if SCL then 0x5D
if (!cap.begin(0x5A)) {
Serial.println("MPR121 not found, check wiring?");
while (1);
}
Serial.println("MPR121 found!");
}
void loop() {
// Get the currently touched pads
currtouched = cap.touched();
for (uint8_t i=0; i<12; i++) {
// it if *is* touched and *wasnt* touched before, alert!
if ((currtouched & _BV(i)) && !(lasttouched & _BV(i)) ) {
Serial.print(i); Serial.println(" touched");
}
// if it *was* touched and now *isnt*, alert!
if (!(currtouched & _BV(i)) && (lasttouched & _BV(i)) ) {
Serial.print(i); Serial.println(" released");
}
}
// reset our state
lasttouched = currtouched;
// comment out this line for detailed data from the sensor!
return;
// debugging info, what
Serial.print("\t\t\t\t\t\t\t\t\t\t\t\t\t 0x"); Serial.println(cap.touched(), HEX);
Serial.print("Filt: ");
for (uint8_t i=0; i<12; i++) {
Serial.print(cap.filteredData(i)); Serial.print("\t");
}
Serial.println();
Serial.print("Base: ");
for (uint8_t i=0; i<12; i++) {
Serial.print(cap.baselineData(i)); Serial.print("\t");
}
Serial.println();
// put a delay so it isn't overwhelming
delay(100);
}
Thanks in advance for any help!
