main.cpp

00001 #include "mbed.h"
00002 
00003 AnalogIn gsr(A0);
00004 DigitalOut buzzer(D5);
00005 
00006 float gsrValue = 0;
00007 float baseline = 0;
00008 int on = 1, off = 0;
00009 
00010 // calculate baseline to compare against
00011 void Get_Baseline(void)
00012 {
00013     double sum = 0;
00014     buzzer = off;
00015     wait(1);
00016     for(int i=0; i<500; i++) {
00017         gsrValue = gsr;
00018         sum += gsrValue;
00019         wait(0.005);
00020     }
00021     baseline = sum/500;
00022     printf("baseline = %f\n\r", baseline);
00023 }
00024 
00025 // main loop, compare against baseline
00026 // sound buzzer if a >5% change happens
00027 int main()
00028 {
00029     float delta;
00030     Get_Baseline();
00031     while(1) {
00032         gsrValue = gsr;
00033         printf("gsrValue = %f\n\r",gsrValue);
00034         delta = baseline - gsrValue;
00035         if(abs(delta) > 0.05) { // check for > 5% change
00036             gsrValue = gsr;
00037             delta = baseline - gsrValue;
00038             if(abs(delta) > 0.05) { // double check
00039                 buzzer = on;
00040                 printf("YES!\n\r");
00041                 wait(3);
00042                 buzzer = off;
00043                 wait(1);
00044             }
00045         }
00046     }
00047 }