Fab Academy 2020 - Lucas Lim
My Final Project Programming & Testing of Electronics

1) Testing all my electronics components (dust sensor module, LCD display module with I2C adaptor, buzzer) as well as the wires with my (Arduino Uno) reference board. All modules and wires are working ok.

2) Following the instructions to install ATMega328P board for Arduino IDE at MCUdude/MiniCore github website https://github.com/MCUdude/MiniCore#supported-microcontrollers

3) Burning the bootloader to my board

4) Standard Arduino UNO pinout diagram mapping for my ATmega328P
(Source : MCUdude/MiniCore github website)

5) Modifying the pin to match my board from the Arduino Uno board and uploading my code to the board. My code uses 7314 byte or 22% of program storage space.

6) Connecting all the pieces together

/*
  Title: PMS5003_dust_sensor_ver3.0.ino
  by Lucas Lim
  Date Created: 16/6/2020
  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

   The work is provided for academic purpose for Fab Academy 2020.
   Users accept all as is, no warranty is provided, no call/email
   from users will get a response. Users accept all liability.
*/

// 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();

  // 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)) {
    //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;
}