Team S - EDP 2 / Mbed 2 deprecated signal_processing

Important changes to repositories hosted on mbed.com

Mbed hosted mercurial repositories are deprecated and are due to be permanently deleted in July 2026.

To keep a copy of this software download the repository Zip archive or clone locally using Mercurial.

It is also possible to export all your personal repositories from the account settings page.

Dependencies:   mbed

main.cpp@4:878821708feb, 2018-02-14 (annotated)

Committer:
2236693B
Date:
Wed Feb 14 11:56:50 2018 +0000
Revision:
4:878821708feb
Parent:
3:c9f4c9c84e36
Child:
5:651843de21ce
Commented;

Who changed what in which revision?

UserRevisionLine numberNew contents of line
2236693B 1:d1e89afbe50c 1 //Rango says, hey there Conor!
2236693B 0:005922ecb765 2
2236693B 0:005922ecb765 3 #include "mbed.h"
2236693B 0:005922ecb765 4
2236693B 0:005922ecb765 5 DigitalOut myled(LED1);
2236693B 0:005922ecb765 6 AnalogIn Ain(PTB1);
2236693B 0:005922ecb765 7
2236693B 2:29c3d03c9231 8 int const MAX_B = 10;
2236693B 3:c9f4c9c84e36 9 int const alpha = 0.5;
2236693B 2:29c3d03c9231 10 int const AVG_LEN = 160;
2236693B 2:29c3d03c9231 11
2236693B 2:29c3d03c9231 12 int sample_buffer[2*MAX_B] = {};
2236693B 2:29c3d03c9231 13 int local_buffer[2*MAX_B] = {};
2236693B 2:29c3d03c9231 14 int avg_buffer[AVG_LEN] = {};
2236693B 0:005922ecb765 15 int read = 0;
2236693B 0:005922ecb765 16 int write = 0;
2236693B 0:005922ecb765 17
2236693B 2:29c3d03c9231 18 int avg_write = 0;
2236693B 2:29c3d03c9231 19
2236693B 2:29c3d03c9231 20 int avg_sum;
2236693B 3:c9f4c9c84e36 21 bool first;
2236693B 3:c9f4c9c84e36 22 float avg;
2236693B 3:c9f4c9c84e36 23 float pre_avg;
2236693B 2:29c3d03c9231 24
2236693B 2:29c3d03c9231 25 Ticker sampler;
2236693B 2:29c3d03c9231 26
2236693B 4:878821708feb 27 void sampling () { //Sample Signal
2236693B 2:29c3d03c9231 28 unsigned int sample = Ain.read_u16();
2236693B 2:29c3d03c9231 29 sample_buffer[write++] = sample;
2236693B 2:29c3d03c9231 30 write = write%(2*MAX_B);
2236693B 2:29c3d03c9231 31
2236693B 2:29c3d03c9231 32 }
2236693B 2:29c3d03c9231 33
2236693B 4:878821708feb 34 float scale (float point) { //Multiply by scale factor
2236693B 3:c9f4c9c84e36 35 return point*7 ;
2236693B 3:c9f4c9c84e36 36 }
2236693B 3:c9f4c9c84e36 37
2236693B 4:878821708feb 38 float filter (float output) { //Filter signal digtally to make more precise
2236693B 3:c9f4c9c84e36 39 float point = alpha*output + (1- alpha)*pre_avg;
2236693B 3:c9f4c9c84e36 40 point = scale(point);
2236693B 3:c9f4c9c84e36 41 return point;
2236693B 3:c9f4c9c84e36 42 }
2236693B 3:c9f4c9c84e36 43
2236693B 4:878821708feb 44 float get_trend(){ //Normalise signal by removing trend
2236693B 3:c9f4c9c84e36 45 float point;
2236693B 3:c9f4c9c84e36 46 pre_avg = avg;
2236693B 3:c9f4c9c84e36 47 avg = avg_sum/AVG_LEN;
2236693B 4:878821708feb 48 int normalised = avg_buffer[avg_write-1] - avg;
2236693B 4:878821708feb 49 point = filter(normalised);
2236693B 3:c9f4c9c84e36 50
2236693B 3:c9f4c9c84e36 51 return point;
2236693B 3:c9f4c9c84e36 52
2236693B 3:c9f4c9c84e36 53
2236693B 3:c9f4c9c84e36 54 }
2236693B 3:c9f4c9c84e36 55
2236693B 4:878821708feb 56 float normalise() { //Normalise values
2236693B 3:c9f4c9c84e36 57 float point ;
2236693B 2:29c3d03c9231 58 if (first) {
2236693B 2:29c3d03c9231 59 for (int i =0; i <MAX_B; i++) {
2236693B 2:29c3d03c9231 60 avg_buffer[avg_write] = local_buffer[i];
2236693B 2:29c3d03c9231 61 avg_write = (++avg_write) % AVG_LEN;
2236693B 2:29c3d03c9231 62 }
2236693B 2:29c3d03c9231 63 if (write == 0) {
2236693B 2:29c3d03c9231 64 first = false;
2236693B 2:29c3d03c9231 65 }
2236693B 2:29c3d03c9231 66 }
2236693B 2:29c3d03c9231 67 else {
2236693B 2:29c3d03c9231 68 for (int i =0; i <MAX_B; i++) {
2236693B 2:29c3d03c9231 69 int data = local_buffer[i];
2236693B 2:29c3d03c9231 70 avg_sum = avg_sum + data - avg_buffer[avg_write];
2236693B 2:29c3d03c9231 71
2236693B 2:29c3d03c9231 72 avg_buffer[avg_write] = data;
2236693B 2:29c3d03c9231 73 avg_write = (++avg_write) % AVG_LEN;
2236693B 3:c9f4c9c84e36 74 point = get_trend();
2236693B 2:29c3d03c9231 75
2236693B 2:29c3d03c9231 76 }
2236693B 2:29c3d03c9231 77 }
2236693B 4:878821708feb 78 return point; //The tenth point
2236693B 2:29c3d03c9231 79
2236693B 2:29c3d03c9231 80 }
2236693B 2:29c3d03c9231 81
2236693B 4:878821708feb 82 float data_process() {
2236693B 4:878821708feb 83 return normalise();
2236693B 0:005922ecb765 84 }
2236693B 0:005922ecb765 85
2236693B 4:878821708feb 86 void write_to_display(float output) {
2236693B 4:878821708feb 87 }
2236693B 4:878821708feb 88
2236693B 4:878821708feb 89 void identify_pulse(float ouput) {
2236693B 4:878821708feb 90
2236693B 4:878821708feb 91
2236693B 4:878821708feb 92 }
2236693B 0:005922ecb765 93 int main() {
2236693B 0:005922ecb765 94 sampler.attach(&sampling, 0.0125); //Sample at 80Hz
2236693B 0:005922ecb765 95
2236693B 0:005922ecb765 96 while(1) {
2236693B 2:29c3d03c9231 97 if (write-read > MAX_B || read-write > MAX_B) { // |write-read| > MAX_B/2
2236693B 0:005922ecb765 98 for(int i = 0; i < MAX_B/2; i++) {
2236693B 0:005922ecb765 99 local_buffer[i] = sample_buffer[read];
2236693B 0:005922ecb765 100 read = (++read) % MAX_B;
2236693B 0:005922ecb765 101 }
2236693B 0:005922ecb765 102 }
2236693B 4:878821708feb 103 float output = data_process();
2236693B 4:878821708feb 104 identify_pulse(output);
2236693B 4:878821708feb 105 write_to_display(output);
2236693B 0:005922ecb765 106 }
2236693B 0:005922ecb765 107 }
2236693B 0:005922ecb765 108
2236693B 0:005922ecb765 109
2236693B 0:005922ecb765 110