/*
  Title: [For Arduino] PMS5003_dust_sensor_ver3.0.ino
  Author: Lucas Lim 
  Date Created: 16/5/2019
  Last Modified: 14/6/2019
  Purpose: Receive data from PMS Dust Sensor Module
           and display PM2.5 and PM10 results to LCD display module. 
           with I2C adaptor.
           Sound buzzer if pre-defined unhealthy limit is reach or exceeded.
           (Optional) Output result to PC via serial communication.           
  PS : The code for the PMS5003 dust sensor module was adapted and modified 
       from the orignal code by Lady Ada published on
       https://learn.adafruit.com/pm25-air-quality-sensor/arduino-code
*/

// I2C library
#include <Wire.h>

// LCD with I2C library
#include <LiquidCrystal_I2C.h>

#include <SoftwareSerial.h>

// variable declaration
// const value will not change
//const int ledpin=2;          // LED connected to PD2 on Arduino pin 2(not use)
const int buzzpin=5;         // buzzer connected to PD5 on Arduino pin 5
const int pms5003_RX = 17;    // PMS5003 dust sensor Rx, on Arduino pin 17
const int pms5003_TX = 16;    // PMS5003 dust sensor Tx, on Arduino pin 16(not use)
int pms_interval_time=2000; // PMS5003 delay time between taking next reading, 1000 = 1sec


SoftwareSerial pmsSerial(pms5003_RX, pms5003_TX);

LiquidCrystal_I2C lcd(0x3F, 16, 2);  // set the LCD address to 0x3F for a 16 chars and 2 line display

 
void setup() {
  // our debugging, output to serial on PC
  //Serial.begin(115200);
 
  // sensor baud rate is 9600
  pmsSerial.begin(9600);

  Wire.begin();
  
  // Initialize the LCD, must be called in order to initialize I2C communication
  lcd.begin();

  // Turn on the backlight
  lcd.backlight();

  // Display to LCD starting up message (not use)
  //lcd.setCursor(0, 0);  
  //lcd.print("Staring up");
  //delay(3000);
  // Clear the LCD
  //lcd.clear();

  // Buzzer
  pinMode(buzzpin,OUTPUT);

  // LED - for power status indicator (not use as LCD display is lit up already)
  //pinMode(ledpin,OUTPUT);
}
 
struct pms5003data {
  uint16_t framelen;
  uint16_t pm10_standard, pm25_standard, pm100_standard;
  uint16_t pm10_env, pm25_env, pm100_env;
  uint16_t particles_03um, particles_05um, particles_10um, particles_25um, particles_50um, particles_100um;
  uint16_t unused;
  uint16_t checksum;
};
 
struct pms5003data data;
    
void loop() {
  if (readPMSdata(&pmsSerial)) {
    // reading data was successful!
    //Serial.println();
    //Serial.println("---------------------------------------");
    //Serial.println("Concentration Units (standard)");
    //Serial.print("\t\tPM 2.5: "); Serial.print(data.pm25_standard);
    //Serial.print("\t\tPM 10: "); Serial.println(data.pm100_standard);
    //Serial.println("---------------------------------------");


    //Output PM2.5 and PM10 measurements to LCD display
    //LCD first row display PM10
    lcd.setCursor(0, 0);  
    lcd.print("PM10 :");
    lcd.setCursor(8, 0);  
    lcd.print(data.pm100_standard);

    //LCD second row display PM2.5
    lcd.setCursor(0,1);
    lcd.print("PM2.5 :");
    lcd.setCursor(8, 1);  
    lcd.print(data.pm25_standard);


    // Sound off buzzer if PM2.5 or PM10 read the 'moderate polluted range'
    //   Good :                PM10 (1-50) PM2.5(0-30)
    //   Satisfactory :        PM10 (51-100) PM2.5(31-60)
    //   Moderately polluted : PM10 (101-250) PM2.5(61-90)
    //   Poor : PM10 (251-350) PM2.5(91-120)
    //   Very poor : PM10 (351-430) PM2.5(121-250)
    //   Severe : PM10 (430+) PM2.5(250+)

    if (data.pm100_standard >= 251) {
      tone(buzzpin, 1000, 10000);        //turns on buzzer, tone( pin number, frequency in hertz, in milliseconds)
      //Serial.print("Buzzer sounded. PM10 reach or exceed limit!");
      lcd.setCursor(0, 0);  
      lcd.print("PM10 :");
      lcd.setCursor(8, 0);  
      lcd.print(data.pm100_standard);
      lcd.setCursor(20, 0);  
      lcd.print("!!!");
      } else {
      noTone(buzzpin);
      }

    if (data.pm25_standard >= 91) {
      tone(buzzpin, 1000, 10000);       //turns on buzzer, tone( pin number, frequency in hertz, in milliseconds)
      //Serial.print("Buzzer sounded. PM2.5 reach or  limit!");
      lcd.setCursor(0,1);
      lcd.print("PM2.5 :");
      lcd.setCursor(8, 1);  
      lcd.print(data.pm25_standard);
      lcd.setCursor(20, 1);  
      lcd.print("!!!");
      } else {
      noTone(buzzpin);
      }
  }

  // Wait for xx seconds before PMS5003 take next reading
  delay(pms_interval_time);

}
 
boolean readPMSdata(Stream *s) {
  if (! s->available()) {
    return false;
  }
  
  // Read a byte at a time until we get to the special '0x42' start-byte
  if (s->peek() != 0x42) {
    s->read();
    return false;
  }
 
  // Now read all 32 bytes
  if (s->available() < 32) {
    return false;
  }
    
  uint8_t buffer[32];    
  uint16_t sum = 0;
  s->readBytes(buffer, 32);
 
  // get checksum ready
  for (uint8_t i=0; i<30; i++) {
    sum += buffer[i];
  }
 
  /* debugging
  for (uint8_t i=2; i<32; i++) {
    Serial.print("0x"); Serial.print(buffer[i], HEX); Serial.print(", ");
  }
  Serial.println();
  */
  
  // The data comes in endian'd, this solves it so it works on all platforms
  uint16_t buffer_u16[15];
  for (uint8_t i=0; i<15; i++) {
    buffer_u16[i] = buffer[2 + i*2 + 1];
    buffer_u16[i] += (buffer[2 + i*2] << 8);
  }
 
  // put it into a nice struct :)
  memcpy((void *)&data, (void *)buffer_u16, 30);
 
  if (sum != data.checksum) {
    //Serial.println("Checksum failure");
    return false;
  }
  // success!
  return true;
}