File content as of revision 1:0d62559f43af:

#include "mbed.h"
#include "HIDScope.h"
#include "BiQuad.h"

//Define EMG input 
AnalogIn    emg0( A0 );
AnalogIn    emg1( A1 );
AnalogIn    emg2( A2 );

Ticker      sample_timer;
HIDScope    scope( 3 );     // 3-channel HIDScope object

// Filter coordinates of lowpass/highpass filter before rectifier and lowpassfilter for the envelope
const double b0_low = 0.2929, b1_low = 0.5858, b2_low = 0.2929, a1_low = 0, a2_low = 0.1716;
const double b0_high = 0.9912, b1_high = -1.9823, b2_high = 0.9912, a1_high = -1.9822, a2_high = 0.9824;
const double b0_envelope = 6.1006E-5, b1_envelope = 1.2201E-4, b2_envelope = 6.1006E-5, a1_envelope = -1.9776, a2_envelope = 0.9780;

double y1, y2, y3;          // Gefilterde output

// Biquad filters (lowpass and highpass become a chain in the int main)
BiQuad lowpass(b0_low, b1_low , b2_low, a1_low, a2_low);
BiQuad highpass(b0_high, b1_high , b2_high, a1_high, a2_high);
BiQuad envelope(b0_envelope, b1_envelope , b2_envelope, a1_envelope, a2_envelope);
BiQuadChain bandpass;

// Sample function, this function samples the emg and sends it to HIDScope

void filtering()
{
   y1 = bandpass.step(emg0);
   y2 = bandpass.step(emg1);
   y3 = bandpass.step(emg2);
   y1 = fabs(y1);
   y2 = fabs(y2);
   y3 = fabs(y3);
   y1 = envelope.step(y1); 
   y2 = envelope.step(y2); 
   y3 = envelope.step(y3); 
    
    // Set the sampled and filtered emg values in channel 0/1/2 in the 'HIDScope' instance named 'scope' 
    scope.set(0, y1 );
    scope.set(1, y2 );
    scope.set(2, y3 );
    
    scope.send();                           // Sends all channels to the PC at once
}

int main()
{   
    bandpass.add(&lowpass).add(&highpass);
    sample_timer.attach(&filtering, 0.001);    // Attach the 'sample' function to the timer 'sample_timer'. This ensures that 'sample' is executed every 0.001 seconds = 1000 Hz
    
    while(1) {}                             // Empty loop, sample() is executed periodically
}