File content as of revision 1:ee877d784c40:

#include "mbed.h"
//#include "read_filter_emg.h"
//included for fabs() function
#include <math.h>
#include "HIDScope.h"
#include <iostream>

Ticker HIDScope_timer;
Ticker Filteren_timer;
HIDScope scope(2);

// defining flags
volatile bool Flag_filteren = false;
volatile bool Flag_HIDScope = false;

// making function flags.
void Go_flag_filteren()
{
    Flag_filteren = true;
}

void Go_flag_HIDScope()
{
    Flag_HIDScope  = true;
}

AnalogIn analog_emg_left(A0);
//AnalogIn analog_emg_right(A1);
double input = 0;
double filter_signal_hid = 0;
//double input_right = 0;

double low_v11=0;
double low_v21=0;
double low_v12=0;
double low_v22=0;
double low_v13=0;
double low_v23=0;
//double v1_right=0;
//double v2_right=0;

double filter_left;
double filter_right;

//general biquad filter that can be called in all the filter functions
double biquad(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;
    //values of v2 and v1 are updated, as they are passed by reference
    //they update globally
    v2 = v1;
    v1 = v;
    return y;
}



/* lowpass filter consists of three cascaded biquads
below the coefficients for those three biquads */
//first low pass biquad
const double lowp1_a1 = -1.05207469728;
const double lowp1_a2 = 0.28586907478;
const double lowp1_b0 = 1.00000000000;
const double lowp1_b1 = 2.00000000000;
const double lowp1_b2 = 1.00000000000;

//second low pass biquad
const double lowp2_a1 = -1.16338171052;
const double lowp2_a2 = 0.42191097989;
const double lowp2_b0 = 1.00000000000;
const double lowp2_b1 = 2.00000000000;
const double lowp2_b2 = 1.00000000000;

//third low pass biquad
const double lowp3_a1 = -1.42439823874;
const double lowp3_a2 = 0.74093118112;
const double lowp3_b0 = 1.00000000000;
const double lowp3_b1 = 2.00000000000;
const double lowp3_b2 = 1.00000000000;







//highpass



/*
//rectifier
double rectify(double y6)
{
    y6 = fabs(y6);
    return y6;
}
*/
//lowpass



   
    // double y8 = biquad(y7, v1, v2, lowp2_a1, lowp2_a2, lowp2_b0, lowp2_b1, lowp2_b2);






double Filteren()
{
    input = analog_emg_left.read();
    //input = input-0.45; //FIRST SUBTRACT MEAN THEN FILTER
    //input_right = analog_emg_right.read();
  double y7 = biquad(input, low_v11, low_v21, lowp1_a1, lowp1_a2, lowp1_b0, lowp1_b1, lowp1_b2);
    double y8 = biquad(y7, low_v12, low_v22, lowp2_a1, lowp2_a2, lowp2_b0, lowp2_b1, lowp2_b2);
    double filter_signal = biquad(y8, low_v13, low_v23, lowp3_a1, lowp3_a2, lowp3_b0, lowp3_b1, lowp3_b2);
    //filter_right = filter(input_right, v1_right, v2_right);
    
return(filter_signal);
}
void HIDScope_kijken()
{
    scope.set(0, input);
    scope.set(1, filter_signal_hid);
    scope.send();
}
int main()
{
    HIDScope_timer.attach(&Go_flag_HIDScope, 0.002);
    Filteren_timer.attach(&Go_flag_filteren,0.004);
    while(1){
              if(Flag_filteren) {
            Flag_filteren = false;
            filter_signal_hid = Filteren();
        }

        if(Flag_HIDScope) {
            Flag_HIDScope = false;
            HIDScope_kijken();
        }
        }
}