Trill/general-print/render.cpp

Trill Print Raw Values

This example will work with all types of Trill sensor and will print the raw reading from each pad.

We are using the Trill library to read from the sensor. The first thing to do is make sure that the correct sensor type is given to touchSensor.setup(). If you have changed the address of the sensor then you will need to add the new address that to this function too.

The Trill sensor is scanned on an auxiliary task running parallel to the audio thread and is read in DIFF mode giving the differential reading of each pad on the sensor.

Once you run the project you will see the value of each capacitive pad on the sensor being printed. This is a good project to run to debug your sensors and make sure they are connected correctly.

/*
 ____  _____ _        _
| __ )| ____| |      / \
|  _ \|  _| | |     / _ \
| |_) | |___| |___ / ___ \
|____/|_____|_____/_/   \_\
http://bela.io
*/
 
#include <Bela.h>
#include <libraries/Trill/Trill.h>
 
Trill touchSensor;
 
// Interval for reading from the sensor
int gPrintInterval = 500; //ms
int gPrintIntervalSamples = 0;
// Sleep time for auxiliary task
unsigned int gTaskSleepTime = 12000; // microseconds
 
void loop(void*)
{
        while(!Bela_stopRequested()) {
                touchSensor.readI2C();
                usleep(gTaskSleepTime);
        }
}
 
bool setup(BelaContext *context, void *userData)
{
        // Setup a Trill Craft on i2c bus 1, using the default address.
        // Set it to differential mode for bargraph display
        if(touchSensor.setup(1, Trill::CRAFT) != 0) {
                fprintf(stderr, "Unable to initialise Trill Craft\n");
                return false;
        }
        // ensure the device is in DIFF mode for printing raw values
        touchSensor.setMode(Trill::DIFF);
        touchSensor.printDetails();
 
        Bela_runAuxiliaryTask(loop);
 
        gPrintIntervalSamples = context->audioSampleRate*(gPrintInterval/1000.0);
        return true;
}
 
void render(BelaContext *context, void *userData)
{
        static int readCount = 0;
        for(unsigned int n = 0; n < context->audioFrames; n++) {
                if(readCount >= gPrintIntervalSamples) {
                        readCount = 0;
                        for(unsigned int i = 0; i < touchSensor.getNumChannels(); i++)
                                rt_printf("%1.3f ", touchSensor.rawData[i]);
                        rt_printf("\n");
                }
                readCount++;
        }
}
 
void cleanup(BelaContext *context, void *userData)
{
}