robert@464: /*
robert@464:  ____  _____ _        _    
robert@464: | __ )| ____| |      / \   
robert@464: |  _ \|  _| | |     / _ \  
robert@464: | |_) | |___| |___ / ___ \ 
robert@464: |____/|_____|_____/_/   \_\
robert@464: 
robert@464: The platform for ultra-low latency audio and sensor processing
robert@464: 
robert@464: http://bela.io
robert@464: 
robert@464: A project of the Augmented Instruments Laboratory within the
robert@464: Centre for Digital Music at Queen Mary University of London.
robert@464: http://www.eecs.qmul.ac.uk/~andrewm
robert@464: 
robert@464: (c) 2016 Augmented Instruments Laboratory: Andrew McPherson,
robert@464:   Astrid Bin, Liam Donovan, Christian Heinrichs, Robert Jack,
robert@464:   Giulio Moro, Laurel Pardue, Victor Zappi. All rights reserved.
robert@464: 
robert@464: The Bela software is distributed under the GNU Lesser General Public License
robert@464: (LGPL 3.0), available here: https://www.gnu.org/licenses/lgpl-3.0.txt
robert@464: */
robert@464: 
robert@464: 
robert@464: #include <Bela.h>
robert@464: #include <cmath>
robert@464: #include <rtdk.h>
robert@464: #include "I2C_MPR121.h"
robert@464: 
robert@464: // How many pins there are
robert@464: #define NUM_TOUCH_PINS 12
robert@464: 
robert@464: // Define this to print data to terminal
robert@464: #undef DEBUG_MPR121
robert@464: 
robert@464: // Change this to change how often the MPR121 is read (in Hz)
robert@464: int readInterval = 50;
robert@464: 
robert@464: // Change this threshold to set the minimum amount of touch
robert@464: int threshold = 40;
robert@464: 
robert@464: // This array holds the continuous sensor values
robert@464: int sensorValue[NUM_TOUCH_PINS];
robert@464: 
robert@464: // ---- test code stuff -- can be deleted for your example ----
robert@464: 
robert@464: // 12 notes of a C major scale...
robert@464: float gFrequencies[NUM_TOUCH_PINS] = {261.63, 293.66, 329.63, 349.23, 392.00, 440.00, 493.88, 523.25, 587.33, 659.25, 698.25, 783.99};
robert@464: 
robert@464: // This is internal stuff for the demo
robert@464: float gNormFrequencies[NUM_TOUCH_PINS];
robert@464: float gPhases[NUM_TOUCH_PINS] = {0};
robert@464: 
robert@464: // ---- internal stuff -- do not change -----
robert@464: 
robert@464: I2C_MPR121 mpr121;			// Object to handle MPR121 sensing
robert@464: AuxiliaryTask i2cTask;		// Auxiliary task to read I2C
robert@464: 
robert@464: int readCount = 0;			// How long until we read again...
robert@464: int readIntervalSamples = 0; // How many samples between reads
robert@464: 
robert@464: void readMPR121();
robert@464: 
robert@464: // setup() is called once before the audio rendering starts.
robert@464: // Use it to perform any initialisation and allocation which is dependent
robert@464: // on the period size or sample rate.
robert@464: //
robert@464: // userData holds an opaque pointer to a data structure that was passed
robert@464: // in from the call to initAudio().
robert@464: //
robert@464: // Return true on success; returning false halts the program.
robert@464: 
robert@464: bool setup(BelaContext *context, void *userData)
robert@464: {
robert@464: 	if(!mpr121.begin(1, 0x5A)) {
robert@464: 		rt_printf("Error initialising MPR121\n");
robert@464: 		return false;
robert@464: 	}
robert@464: 	
robert@464: 	i2cTask = Bela_createAuxiliaryTask(readMPR121, 50, "bela-mpr121");
robert@464: 	readIntervalSamples = context->audioSampleRate / readInterval;
robert@464: 	
robert@464: 	for(int i = 0; i < NUM_TOUCH_PINS; i++) {
robert@464: 		gNormFrequencies[i] = 2.0 * M_PI * gFrequencies[i] / context->audioSampleRate;
robert@464: 	}
robert@464: 	
robert@464: 	return true;
robert@464: }
robert@464: 
robert@464: // render() is called regularly at the highest priority by the audio engine.
robert@464: // Input and output are given from the audio hardware and the other
robert@464: // ADCs and DACs (if available). If only audio is available, numAnalogFrames
robert@464: // will be 0.
robert@464: 
robert@464: void render(BelaContext *context, void *userData)
robert@464: {
robert@464: 	for(int n = 0; n < context->audioFrames; n++) {
robert@464: 		// Keep this code: it schedules the touch sensor readings
robert@464: 		if(++readCount >= readIntervalSamples) {
robert@464: 			readCount = 0;
robert@464: 			Bela_scheduleAuxiliaryTask(i2cTask);
robert@464: 		}
robert@464: 		
robert@464: 		float sample = 0.0;
robert@464: 		
robert@464: 		// This code can be replaced with your favourite audio code
robert@464: 		for(int i = 0; i < NUM_TOUCH_PINS; i++) {
robert@464: 			float amplitude = sensorValue[i] / 400.0;
robert@464: 			
robert@464: 			// Prevent clipping
robert@464: 			if(amplitude > 0.5)
robert@464: 				amplitude = 0.5;
robert@464: 			
robert@464: 			sample += amplitude * sinf(gPhases[i]);
robert@464: 			gPhases[i] += gNormFrequencies[i];
robert@464: 			if(gPhases[i] > 2.0 * M_PI)
robert@464: 				gPhases[i] -= 2.0 * M_PI;
robert@464: 		}
robert@464: 		
robert@464: 		for(int ch = 0; ch < context->audioChannels; ch++)
robert@464: 			context->audioOut[context->audioChannels * n + ch] = sample;
robert@464: 	}
robert@464: }
robert@464: 
robert@464: // cleanup() is called once at the end, after the audio has stopped.
robert@464: // Release any resources that were allocated in setup().
robert@464: 
robert@464: void cleanup(BelaContext *context, void *userData)
robert@464: {
robert@464: 	// Nothing to do here
robert@464: }
robert@464: 
robert@464: 
robert@464: // Auxiliary task to read the I2C board
robert@464: void readMPR121()
robert@464: {
robert@464: 	for(int i = 0; i < NUM_TOUCH_PINS; i++) {
robert@464: 		sensorValue[i] = -(mpr121.filteredData(i) - mpr121.baselineData(i));
robert@464: 		sensorValue[i] -= threshold;
robert@464: 		if(sensorValue[i] < 0)
robert@464: 			sensorValue[i] = 0;
robert@464: #ifdef DEBUG_MPR121
robert@464: 		rt_printf("%d ", sensorValue[i]);
robert@464: #endif
robert@464: 	}
robert@464: #ifdef DEBUG_MPR121
robert@464: 	rt_printf("\n");
robert@464: #endif
robert@464: 	
robert@464: 	// You can use this to read binary on/off touch state more easily
robert@464: 	//rt_printf("Touched: %x\n", mpr121.touched());
robert@464: }
robert@464: 
robert@464: /* ------------ Project Explantation ------------ */
robert@464: 
robert@464: /**
robert@464: \example 06-capacitive-touch
robert@464: 
robert@464: Capacitive touch sensing with MPR121
robert@464: ---------------------------
robert@464: 
robert@464: This sketch allows you to hook up an MPR121 capactive touch sensing device
robert@464: to Bela, for example the SparkFun Capacitive Touch Sensor Breakout - MPR121.
robert@464: The breakout board gives you 12 electrode connections.
robert@464: 
robert@464: To get this working with Bela you need to connect the breakout board to the I2C
robert@464: terminal on the Bela board. See the Pin guide for details of which pin is which.
robert@464: 
robert@464: The sensor data will then be available for you to use in the array 
robert@464: `sensorValue[NUM_TOUCH_PINS]`.
robert@464: */