Kevin Hetterscheid / EMG

emg

Fork of EMG by Tom Tom

emg.cpp@19:34c129b055b6, 2015-10-20 (annotated)

Committer:
AeroKev
Date:
Tue Oct 20 08:00:52 2015 +0000
Revision:
19:34c129b055b6
Parent:
main.cpp@18:e753220c7ba6 
Added .h;

Who changed what in which revision?

UserRevisionLine numberNew contents of line
vsluiter 0:32bb76391d89 1 #include "mbed.h"
vsluiter 11:ce72ec658a95 2 #include "HIDScope.h"
AeroKev 19:34c129b055b6 3 #include "emg.h"
AeroKev 18:e753220c7ba6 4
vsluiter 4:8b298dfada81 5 //Define objects
tomlankhorst 14:f83354387756 6 AnalogIn emg(A0); //Analog input
tomlankhorst 14:f83354387756 7 Ticker sample_timer;
AeroKev 18:e753220c7ba6 8 HIDScope scope(2);
AeroKev 18:e753220c7ba6 9
AeroKev 18:e753220c7ba6 10 double highV[4];
AeroKev 18:e753220c7ba6 11 double lowV[4];
AeroKev 19:34c129b055b6 12 // An array which stores the last MOV_AVG_NUM outputs
AeroKev 18:e753220c7ba6 13 double lastOutputs[MOV_AVG_NUM-1];
AeroKev 19:34c129b055b6 14 // The sum of the last MOV_AVG_NUM outputs
AeroKev 19:34c129b055b6 15 double outputSum;
AeroKev 18:e753220c7ba6 16
AeroKev 18:e753220c7ba6 17 double filter(double input, double coeff_input[], double coeff_output[], double prev_outputs[])
AeroKev 18:e753220c7ba6 18 {
AeroKev 18:e753220c7ba6 19 double new_input = input;
AeroKev 18:e753220c7ba6 20 for(int i=1; i<5; i++)
AeroKev 18:e753220c7ba6 21 new_input -= coeff_input[i] * prev_outputs[i-1];
AeroKev 18:e753220c7ba6 22
AeroKev 18:e753220c7ba6 23 double new_output = coeff_output[0] * new_input;
AeroKev 18:e753220c7ba6 24 for(int i=1; i<5; i++)
AeroKev 18:e753220c7ba6 25 new_output += coeff_output[i] * prev_outputs[i-1];
AeroKev 18:e753220c7ba6 26
AeroKev 18:e753220c7ba6 27 // Set the new output as the first value of the 'recent outputs'
AeroKev 18:e753220c7ba6 28 for(int i = 3; i > 0; i--)
AeroKev 18:e753220c7ba6 29 prev_outputs[i] = prev_outputs[i-1];
AeroKev 18:e753220c7ba6 30 prev_outputs[0] = new_input;
AeroKev 18:e753220c7ba6 31 return new_output;
AeroKev 18:e753220c7ba6 32 }
AeroKev 18:e753220c7ba6 33
AeroKev 18:e753220c7ba6 34 double fh_b[]= {0.7602, -3.0406, 4.5609, -3.0406, 0.7602};
AeroKev 18:e753220c7ba6 35 double fh_a[]= {1, -3.4532, 4.5041, -2.6273, 0.5778};
AeroKev 18:e753220c7ba6 36 double highpass_filter(double u)
AeroKev 18:e753220c7ba6 37 {
AeroKev 18:e753220c7ba6 38 return filter(u, fh_a, fh_b, highV);
AeroKev 18:e753220c7ba6 39 }
AeroKev 18:e753220c7ba6 40
AeroKev 18:e753220c7ba6 41 double fl_b[]= {0.00000658, 0.00002631, 0.00003947, 0.00002631, 0.00000658};
AeroKev 18:e753220c7ba6 42 double fl_a[]= {1.0000, -3.7264, 5.2160, -3.2500, 0.7605};
AeroKev 18:e753220c7ba6 43 double lowpass_filter(double u)
AeroKev 18:e753220c7ba6 44 {
AeroKev 18:e753220c7ba6 45 return filter(u, fl_a, fl_b, lowV);
AeroKev 18:e753220c7ba6 46 }
vsluiter 2:e314bb3b2d99 47
tomlankhorst 14:f83354387756 48 void sample()
vsluiter 2:e314bb3b2d99 49 {
AeroKev 18:e753220c7ba6 50 double input = emg.read();
AeroKev 18:e753220c7ba6 51 double output1 = highpass_filter(input);
AeroKev 18:e753220c7ba6 52 double output2 = fabs(output1);
AeroKev 18:e753220c7ba6 53 double output3 = lowpass_filter(output2);
AeroKev 18:e753220c7ba6 54
AeroKev 19:34c129b055b6 55 /* Calculate the average of the last MOV_AVG_NUM outputs and the new input */
AeroKev 19:34c129b055b6 56 outputSum = outputSum - lastOutputs[MOV_AVG_NUM-2] + output3;
AeroKev 18:e753220c7ba6 57 for(int i=0; i<MOV_AVG_NUM-1; i++) {
AeroKev 18:e753220c7ba6 58 if(i != 0) lastOutputs[i] = lastOutputs[i-1];
AeroKev 18:e753220c7ba6 59 }
AeroKev 18:e753220c7ba6 60 lastOutputs[0] = output3;
AeroKev 19:34c129b055b6 61 output3 = outputSum/MOV_AVG_NUM;
AeroKev 18:e753220c7ba6 62
tomlankhorst 14:f83354387756 63 /* Second, set the sampled emg value in channel zero (the first channel) in the 'HIDScope' variable named 'scope' */
AeroKev 18:e753220c7ba6 64 scope.set(0,input);
AeroKev 18:e753220c7ba6 65 scope.set(1,output3);
tomlankhorst 16:9f7797ffd0fb 66 /* Repeat the step above if required for more channels (channel 0 up to 5 = 6 channels) */
tomlankhorst 14:f83354387756 67 /* Finally, send all channels to the PC at once */
vsluiter 11:ce72ec658a95 68 scope.send();
vsluiter 2:e314bb3b2d99 69 }
vsluiter 0:32bb76391d89 70
AeroKev 19:34c129b055b6 71 /*
vsluiter 0:32bb76391d89 72 int main()
vsluiter 0:32bb76391d89 73 {
AeroKev 19:34c129b055b6 74 //Attach the 'sample' function to the timer 'sample_timer'. this ensures that 'sample' is executed every... 0.002 seconds
AeroKev 19:34c129b055b6 75
tomlankhorst 14:f83354387756 76 sample_timer.attach(&sample, 0.002);
tomlankhorst 15:0da764eea774 77
AeroKev 19:34c129b055b6 78 //empty loop, sample() is executed periodically
tomlankhorst 15:0da764eea774 79 while(1) {}
AeroKev 19:34c129b055b6 80 }*/