Customizable Geiger Muller Counter

1#include <LiquidCrystal_I2C.h>
2#include <Wire.h>
3
4unsigned long  counts; //variable for GM Tube events
5unsigned long previousMillis; //variable  for measuring time
6float averageCPM;
7float sdCPM;
8int currentCPM;
9float  calcCPM;
10LiquidCrystal_I2C lcd(0x27, 20, 4);
11float CPMArray[100];
12
13#define  LOG_PERIOD 30000 // count rate (in milliseconds)
14
15void setup() { //setup
16  counts = 0;
17  currentCPM = 0;
18  averageCPM = 0;
19  sdCPM = 0;
20  calcCPM  = 0;
21  lcd.init();
22  lcd.backlight();
23  Serial.begin(9600);
24  pinMode(2,  INPUT);
25  attachInterrupt(digitalPinToInterrupt(2), impulse, FALLING); //define  external interrupts
26}
27
28void loop() { //main cycle
29  lcd.setCursor(0,2);
30  lcd.print("CPM Count: ");
31  lcd.print(counts);
32  unsigned long currentMillis  = millis();
33  if (currentMillis - previousMillis > LOG_PERIOD) {
34    previousMillis  = currentMillis;
35    CPMArray[currentCPM] = counts * 2;
36    lcd.clear();
37    lcd.setCursor(0,0);
38    lcd.print("uSv/hr: ");
39    lcd.print(outputSieverts(CPMArray[currentCPM]));
40    counts = 0;
41    averageCPM = 0;
42    sdCPM = 0;
43    //calc avg and sd
44    for (int x=0;x<currentCPM+1;x++)  {
45      averageCPM = averageCPM + CPMArray[x];
46    }
47    averageCPM = averageCPM / (currentCPM + 1);
48    for (int x=0;x<currentCPM+1;x++)  {
49      sdCPM = sdCPM + sq(CPMArray[x] - averageCPM);
50    }
51    sdCPM  = sqrt(sdCPM / currentCPM) / sqrt(currentCPM+1);
52
53    Serial.println("Avg:  " + String(averageCPM) + " +/- " + String(sdCPM) + "  ArrayVal: " + String(CPMArray[currentCPM]));
54    currentCPM = currentCPM + 1;
55    displayAverageCPM();
56  } 
57}
58
59void  impulse() {
60  counts++;
61}
62void displayAverageCPM()  {
63  lcd.setCursor(0,1);
64  lcd.print("Avg: ");
65  lcd.print(outputSieverts(averageCPM));
66  lcd.print("+/-");
67  lcd.print(outputSieverts(sdCPM));
68}
69float outputSieverts(float x)  {
70  float y = x * 0.0057;
71  return y;
72}