Numero Uno / EMG

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EMG.h@4:963e903c2236, 2015-10-12 (annotated)

Committer:
mganseij
Date:
Mon Oct 12 16:15:33 2015 +0000
Revision:
4:963e903c2236
Parent:
3:0662d78d9092
Child:
5:7873900f62da
Rewrote calibration function into a single for loop, got rid of the arrays

Who changed what in which revision?

UserRevisionLine numberNew contents of line
ewoud 0:b5f7b64b0fe4 1 #include "biquadFilter.h"
ewoud 0:b5f7b64b0fe4 2 #include <cmath>
ewoud 0:b5f7b64b0fe4 3
ewoud 0:b5f7b64b0fe4 4
mganseij 4:963e903c2236 5 const int Fs = 200; // sampling frequency
mganseij 3:0662d78d9092 6 const double low_b1 = 0.000944691843840; //filter coefficients - second order butterworth filters at 2 hz low and 25 hz high, coefficents based on Fs of 512.
mganseij 3:0662d78d9092 7 const double low_b2 = 0.001889383687680;
mganseij 3:0662d78d9092 8 const double low_b3 = 0.000944691843840;
mganseij 3:0662d78d9092 9 const double low_a2 = -1.911197067426073; // a1 is normalized to 1
mganseij 3:0662d78d9092 10 const double low_a3 = 0.914975834801434;
mganseij 3:0662d78d9092 11 const double high_b1 = 0.569035593728849;
mganseij 3:0662d78d9092 12 const double high_b2 = -1.138071187457699;
mganseij 3:0662d78d9092 13 const double high_b3 = 0.569035593728849;
mganseij 3:0662d78d9092 14 const double high_a2 = -0.942809041582063; // a1 is normalized to 1
mganseij 3:0662d78d9092 15 const double high_a3 = 0.333333333333333;
ewoud 0:b5f7b64b0fe4 16 biquadFilter highpass1(high_a2, high_a3, high_b1, high_b2, high_b3); // different objects for different inputs, otherwise the v1 and v2 variables get fucked up
ewoud 0:b5f7b64b0fe4 17 biquadFilter highpass2(high_a2, high_a3, high_b1, high_b2, high_b3);
ewoud 0:b5f7b64b0fe4 18 biquadFilter highpass3(high_a2, high_a3, high_b1, high_b2, high_b3);
ewoud 0:b5f7b64b0fe4 19 biquadFilter highpass4(high_a2, high_a3, high_b1, high_b2, high_b3);
ewoud 0:b5f7b64b0fe4 20 biquadFilter lowpass1(low_a2, low_a3, low_b1, low_b2, low_b3);
ewoud 0:b5f7b64b0fe4 21 biquadFilter lowpass2(low_a2, low_a3, low_b1, low_b2, low_b3);
ewoud 0:b5f7b64b0fe4 22 biquadFilter lowpass3(low_a2, low_a3, low_b1, low_b2, low_b3);
ewoud 0:b5f7b64b0fe4 23 biquadFilter lowpass4(low_a2, low_a3, low_b1, low_b2, low_b3);
ewoud 0:b5f7b64b0fe4 24
ewoud 0:b5f7b64b0fe4 25 AnalogIn input1(A0); // declaring the 4 inputs
ewoud 0:b5f7b64b0fe4 26 AnalogIn input2(A1);
ewoud 0:b5f7b64b0fe4 27 AnalogIn input3(A2);
ewoud 0:b5f7b64b0fe4 28 AnalogIn input4(A3);
ewoud 0:b5f7b64b0fe4 29 double u1; double y1; // declaring the input variables
ewoud 0:b5f7b64b0fe4 30 double u2; double y2;
ewoud 0:b5f7b64b0fe4 31 double u3; double y3;
ewoud 0:b5f7b64b0fe4 32 double u4; double y4;
ewoud 0:b5f7b64b0fe4 33
ewoud 0:b5f7b64b0fe4 34 Ticker T1;
ewoud 0:b5f7b64b0fe4 35 volatile bool sample_go;
ewoud 0:b5f7b64b0fe4 36
mganseij 3:0662d78d9092 37
ewoud 0:b5f7b64b0fe4 38 InterruptIn cali_button(PTA4); // initialize interrupt button for calibration stuff
mganseij 1:b73e3dc74d7c 39 double cali_fact1 = 8;
mganseij 1:b73e3dc74d7c 40 double cali_fact2 = 8; // calibration factor to normalize filter output to a scale of 0 - 1
mganseij 4:963e903c2236 41
ewoud 0:b5f7b64b0fe4 42
ewoud 0:b5f7b64b0fe4 43 void sample_filter()
ewoud 0:b5f7b64b0fe4 44 {
ewoud 0:b5f7b64b0fe4 45 u1 = input1; u2 = input2; u3 = input3; u4 = input4; // sample
ewoud 0:b5f7b64b0fe4 46 y1 = highpass1.step(u1); y2 = highpass2.step(u2); y3 = highpass3.step(u3); y4 = highpass4.step(u4); // filter order is: high-pass --> rectify --> low-pass
ewoud 0:b5f7b64b0fe4 47 y1 = fabs(y1); y2 = fabs(y2); y3 = fabs(y3); y4 = fabs(y4);
ewoud 2:84ff5b0f5406 48 y1 = lowpass1.step(y1)*cali_fact1; y2 = lowpass2.step(y2)*cali_fact2; y3 = lowpass3.step(y3)*cali_fact1; y4 = lowpass4.step(y4)*cali_fact1; // roughly normalize to a scale of 0 - 1, where 0 is minimum and 1 is roughly the maximum output of dennis.
ewoud 0:b5f7b64b0fe4 49 }
ewoud 0:b5f7b64b0fe4 50
ewoud 0:b5f7b64b0fe4 51 void samplego() // ticker function, set flag to true every sample interval
ewoud 0:b5f7b64b0fe4 52 {
ewoud 0:b5f7b64b0fe4 53 sample_go = 1;
ewoud 0:b5f7b64b0fe4 54 }
ewoud 0:b5f7b64b0fe4 55
ewoud 0:b5f7b64b0fe4 56 void calibrate() // function to calibrate the emg signals from the user. It takes 5 seconds of measurements of maximum output, then takes the max and normalizes to that.
ewoud 0:b5f7b64b0fe4 57 {
mganseij 1:b73e3dc74d7c 58 cali_fact1 = 1; cali_fact2 = 1;
mganseij 4:963e903c2236 59 double cali_max1 = 0; double cali_max2 = 0;
mganseij 4:963e903c2236 60 for(int i = 0; i < 5*Fs; i++)
ewoud 0:b5f7b64b0fe4 61 {
ewoud 0:b5f7b64b0fe4 62 sample_filter();
mganseij 4:963e903c2236 63 if(y1 > cali_max1)
mganseij 4:963e903c2236 64 {
mganseij 4:963e903c2236 65 cali_max1 = y1;
mganseij 4:963e903c2236 66 }
mganseij 4:963e903c2236 67 if(y2 > cali_max2)
mganseij 4:963e903c2236 68 {
mganseij 4:963e903c2236 69 cali_max2 = y2;
mganseij 4:963e903c2236 70 }
mganseij 4:963e903c2236 71 wait(1/Fs);
mganseij 4:963e903c2236 72 }
mganseij 4:963e903c2236 73 cali_fact1 = 1.0/cali_max1;
mganseij 4:963e903c2236 74 cali_fact2 = 1.0/cali_max2;
ewoud 0:b5f7b64b0fe4 75 }
ewoud 0:b5f7b64b0fe4 76
ewoud 0:b5f7b64b0fe4 77 /*
ewoud 0:b5f7b64b0fe4 78 int main()
ewoud 0:b5f7b64b0fe4 79 {
ewoud 0:b5f7b64b0fe4 80 T1.attach(&samplego, (float)1/Fs);
ewoud 0:b5f7b64b0fe4 81 cali_button.rise(&calibrate);
ewoud 0:b5f7b64b0fe4 82 while(1)
ewoud 0:b5f7b64b0fe4 83 {
ewoud 0:b5f7b64b0fe4 84 if(sample_go)
ewoud 0:b5f7b64b0fe4 85 {
ewoud 0:b5f7b64b0fe4 86 sample_filter();
ewoud 0:b5f7b64b0fe4 87 sample_go = 0;
ewoud 0:b5f7b64b0fe4 88 }
ewoud 0:b5f7b64b0fe4 89 } // while end
ewoud 0:b5f7b64b0fe4 90 } // main end
ewoud 0:b5f7b64b0fe4 91 */