File content as of revision 22:ad85b8acf8b5:

#include "mbed.h"
#include "HIDScope.h"
#include "MODSERIAL.h"

//Define objects
AnalogIn    emg0( A0 );
AnalogIn    emg1( A1 );
DigitalIn   buttonCalibrate(SW2);
MODSERIAL pc(USBTX, USBRX);

volatile float x;
volatile float x_prev =0;
volatile float b; // filtered 'output' of ReadAnalogInAndFilter

bool calibrate = false;
double threshold_Left = 0;
double threshold_Right= 0;
Ticker      sample_timer;
HIDScope    scope( 2 );
DigitalOut  led(LED1);
const double a1 = -1.6475;
const double a2 = 0.7009;
const double b0 = 0.8371;
const double b1 = -1.6742;
const double b2 = 0.8371;
const double c1 = -1.9645;
const double c2 = 0.9651;
const double d0 = 0.0001551;
const double d1 = 0.0003103;
const double d2 = 0.0001551;
double v1_high = 0;
double v2_high = 0;
double v1_low = 0;
double v2_low = 0;
double highpassFilterLeft = 0;
double lowpassFilterLeft = 0;
double highpassFilterRight = 0;
double lowpassFilterRight = 0;

double biquad1(double u, double&v1, double&v2, const double a1, const double a2, const double b0,
               const double b1, const double b2)
{
    double v = u - a1*v1 - a2*v2;
    double y = b0*v + b1*v1 + b2*v2;
    v2 = v1;
    v1 = v;
    return y;
}
/*double biquad2(double u, double&v1, double&v2, const double c1, const double c2, const double d0,
               const double d1, const double d2)
{
    double v = u - c1*v1 - c2*v2;
    double y = d0*v + d1*v1 + d2*v2;
    v2 = v1;
    v1 = v;
    return y;
}
*/
/** Sample function
 * this function samples the emg and sends it to HIDScope
 **/

void filterSampleLeft()
{
    highpassFilterLeft = fabs(biquad1(emg0.read(), v1_high, v2_high, a1, a2, b0, b1, b2));
    lowpassFilterLeft = biquad1(highpassFilterLeft, v1_low, v2_low, c1, c2, d0, d1, d2);
    scope.set(0, lowpassFilterLeft );
    scope.send();
    //pc.printf("%f \n \r ", lowpassFilter);
}
void filterSampleRight()
{
    highpassFilterRight = fabs(biquad1(emg1.read(), v1_high, v2_high, a1, a2, b0, b1, b2));
    lowpassFilterRight = biquad1(highpassFilterRight, v1_low, v2_low, c1, c2, d0, d1, d2);
    scope.set(1, lowpassFilterRight );
    scope.send();
    //pc.printf("%f \n \r ", lowpassFilter);
}
void sample()
{
    /* Set the sampled emg values in channel 0 (the first channel) and 1 (the second channel) in the 'HIDScope' instance named 'scope' */
    scope.set(0, emg0.read() );
    scope.set(1, emg1.read() );
    /* Repeat the step above if required for more channels of required (channel 0 up to 5 = 6 channels)
    *  Ensure that enough channels are available (HIDScope scope( 2 ))
    *  Finally, send all channels to the PC at once */

    x = emg0;   // Capture data        scope.set(0, x);   // store data in first element of scope memory
    b = (x_prev + x)/2.0;   // averaging filter
    x_prev = x; // Prepare for next round

    scope.send();
    /* To indicate that the function is working, the LED is toggled */
    led = !led;
    pc.printf("%f, %f \n \r ", x, b);
}

int main()
{
    /**Attach the 'sample' function to the timer 'sample_timer'.
    * this ensures that 'sample' is executed every... 0.002 seconds = 500 Hz
    */
    //sample_timer.attach(&sample, 0.001953125);
    sample_timer.attach(&filterSampleLeft, 0.001953125);        //512 Hz
    sample_timer.attach(&filterSampleRight, 0.001953125);
    pc.baud(115200);
    pc.printf("please push the button to calibrate \n \r");
    while (1) {
        if (buttonCalibrate == 0) {
            calibrate = true;
            threshold_Left = lowpassFilterLeft*0.7;
            threshold_Right = lowpassFilterRight*0.7;
        }
        if (calibrate == true) {
            pc.printf("calibration complete, left = %f, right = %f \n \r", threshold_Left, threshold_Right);
            /*empty loop, sample() is executed periodically*/
        }
    }
}