/* --------------------------------------------------------------------------------------
* WHAT IS CPM?
* CPM (counts per minute) is events quantity from Geiger Tube you get during one minute.
* Usually it used to calculate a radiation level.  
* Different GM Tubes has different quantity of CPM for background.
* Some tubes can produce about 10-50 CPM for normal background,
* other GM Tube models produce 50-100 CPM or 0-5 CPM for same radiation level.
* Please refer your GM Tube datasheet for more information. 
* Just for reference here, SBM-20 can generate about 10-50 CPM for normal background.
* --------------------------------------------------------------------------------------*/

// This Sketch counts the number of pulses a minute.
// Connect the GND on Arduino to the GND on the Geiger counter.
// Connect the 5V on Arduino to the 5V on the Geiger counter.
// Connect the VIN on the Geiger counter to the D2 on Arduino.

// For I2C 1602 LCD : VCC-5V / GND-GND / SDA-A4 / SCL-A5
#include <Wire.h>
#include <LiquidCrystal_I2C.h>

// I2C address: 0x20~0x27 or 0x3F
LiquidCrystal_I2C lcd(0x27, 16, 2);  

int cpm;
float sievertshour; // for converting from cpm to sieverts/hour
//float sieverts; // for converting from cpm to sieverts  
unsigned long counts; //variable for GM Tube events
unsigned long previousMillis; //variable for measuring time

#define LOG_PERIOD 60000 // count rate (1 minute)
#define CONV_FACTOR 0.008120 // for GM tube of J305beta type

void setup() { //setup
  counts = 0;
  Serial.begin(9600);
  pinMode(2, INPUT);

  lcd.init();               // lcd 초기화
  lcd.backlight();
  
  attachInterrupt(digitalPinToInterrupt(2), impulse, FALLING); //define external interrupts
}

void loop() {
  lcd.setCursor(0,0);
  lcd.print("CPM:");
  lcd.setCursor(9,0);
  lcd.print(" #:");
  lcd.setCursor(12,0);
  lcd.print(counts);
  lcd.setCursor(0,1);
  lcd.print("uSv/h:");
  //lcd.print("uSv  :");
  
  unsigned long currentMillis = millis();

  if (currentMillis - previousMillis > LOG_PERIOD) {   //every 1 minute
    previousMillis = currentMillis;

    lcd.clear();
    lcd.setCursor(5, 0);
    cpm = counts;
    lcd.print(cpm); //Display CPM
    Serial.println(cpm);
    sievertshour = cpm * CONV_FACTOR;
    //sieverts = sievertshour * 356 * 24;
    lcd.setCursor(7,1);
    lcd.print(sievertshour);
    //lcd.print(sieverts);
     
    counts = 0;
  }
}

void impulse() { // called every time there is a FALLING signal at pin 2
  counts++;
}

/*************ARDUINO SKETCH FOR GEIGER COUNTER******************
Author: RH Electronics www.radiohobbystore.com / www.mygeiger.org
*****************************************************************
This sketch can be used with DIY Geiger Counter board. It allow
to receive CPM data during minute. You can modify the sketch
for your needs.
*****************************************************************
LCD I2C Connection:
LCD SDA -> D10  =  1
LCD SCL -> D9   =  3
VCC to +3,3V and ground
****************************************************************/

// include the library code:
#include <LiquidCrystal_I2C.h>
#include <SPI.h>
#include <Wire.h>

#define LOG_PERIOD 15000  //Logging period in milliseconds, recommended value 15000-60000.
#define MAX_PERIOD 60000  //Maximum logging period without modifying this sketch
#define PERIOD 60000.0 // (60 sec) one minute measure period

volatile unsigned long CNT; // variable for counting interrupts from dosimeter
unsigned long counts;     //variable for GM Tube events
unsigned long cpm;        //variable for CPM
unsigned int multiplier;  //variable for calculation CPM in this sketch
unsigned long previousMillis;  //variable for time measurement
unsigned long dispPeriod; // variable for measuring time
unsigned long CPM; // variable for measuring CPM

const int inputPin = 4;  // pin D2 is VIN on geiger counter

// initialize the library with the numbers of the interface pins
LiquidCrystal_I2C lcd(0x3F,20,4);

void setup() {               // setup
Wire.begin(1,3);
lcd.begin(20, 4);
lcd.init();
// Turn on the backlight.
lcd.backlight();

CNT = 0;
CPM = 0;
dispPeriod = 0;
attachInterrupt(digitalPinToInterrupt(inputPin), GetEvent, FALLING); // Define interrupt D2 on falling edge
}

void loop() {           // main loop
lcd.setCursor(0,0);
lcd.print("Berlin-Siemensstadt");
lcd.setCursor(0,1);
lcd.print("   Geiger Counter ");
lcd.setCursor(0,2); // print text and CNT on the LCD
lcd.print("CPM:");
lcd.setCursor(0,3);
lcd.print("CNT:");
lcd.setCursor(5,3);
lcd.print(CNT);
if (millis() >=dispPeriod + PERIOD) { // If one minute is over
cleanDisplay(); // Clear LCD
// Do something about accumulated CNT events....
lcd.setCursor(5, 2);
CPM = CNT;
lcd.print(CPM); //Display CPM
CNT = 0;
dispPeriod = millis();
}
}

void GetEvent(){           // Get Event from Device
CNT++;
}

void cleanDisplay (){      // Clear LCD routine
lcd.clear();
lcd.setCursor(0,0);
lcd.setCursor(0,0);
}