Free Fall Detection Using 3-Axis Accelerometer

1#include <Esplora.h>
2
3void setup()
4{
5  Serial.begin(9600);        
6}
7
8void loop()
9{
10  long int xa = Esplora.readAccelerometer(X_AXIS);   
11  long int ya = Esplora.readAccelerometer(Y_AXIS);
12  long int za = Esplora.readAccelerometer(Z_AXIS);
13  float at = sqrt(xa*xa + ya*ya + za*za);           // total acceleration
14  Serial.print(xa);
15  Serial.print('\	');
16  Serial.print(ya);
17  Serial.print('\	');
18  Serial.print(za);
19  Serial.print('\	');
20  Serial.print(at);
21  Serial.println();  
22    
23    // since esplora accelerometer output is in 0 to 1023 range, we can assume that  the acceleration during free fall will drop below value 50.
24    
25    if (at  < 50) {
26        Esplora.writeRGB(255,0,0);
27    }
28    else {
29        Esplora.writeRGB(0,0,0);
30    }
31
32
33  delay(10);         
34}
35
36
37