A Geiger Counter Simulator

1#define CLIK 8
2#define ECHO 2
3#define TRIG 3
4
5#define c 340.e-6  // the speed of sound
6
7void setup() {
8  pinMode(CLIK, OUTPUT);
9  pinMode(ECHO,  INPUT);
10  pinMode(TRIG, OUTPUT);
11  digitalWrite(TRIG, LOW);
12  digitalWrite(CLIK,  LOW);
13}
14
15void trigger() {
16  /* trigger the sensor */
17  digitalWrite(TRIG,  HIGH);
18  delayMicroseconds(10);
19  digitalWrite(TRIG, LOW);
20}
21
22float  measure() {
23  /* measure the distance between the sensor and the obstacle */
24  float d = 0.;
25  for (int i = 0; i < 15; i++) {
26    trigger();
27    unsigned  long T = pulseIn(ECHO, HIGH);
28    d += c*T/2.;
29  }
30  return d;
31}
32
33int  status = HIGH; // the current status of the relay
34
35void loop() {
36  float  d = measure();
37  unsigned long trigger = 1000./(d*d); 
38  unsigned long r =  random(1000);
39  if (r < trigger) {
40    digitalWrite(CLIK, status);
41    if  (status == HIGH) {
42      status = LOW;
43    } else {
44      status = HIGH;
45    }
46  }
47}
48