/*
 * The MySensors Arduino library handles the wireless radio link and protocol
 * between your home built sensors/actuators and HA controller of choice.
 * The sensors forms a self healing radio network with optional repeaters. Each
 * repeater and gateway builds a routing tables in EEPROM which keeps track of the
 * network topology allowing messages to be routed to nodes.
 *
 * Created by Henrik Ekblad <henrik.ekblad@mysensors.org>
 * Copyright (C) 2013-2019 Sensnology AB
 * Full contributor list: https://github.com/mysensors/MySensors/graphs/contributors
 *
 * Documentation: http://www.mysensors.org
 * Support Forum: http://forum.mysensors.org
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * version 2 as published by the Free Software Foundation.
 *
 *******************************
 *
 * DESCRIPTION
 *
 * Dust Sensor for SamYoung DSM501
 *   connect the sensor as follows :
 *    Pin 2 of dust sensor PM1      -> Digital 3 (PMW)
 *	  Pin 3 of dust sensor          -> +5V
 * 	  Pin 4 of dust sensor PM2.5    -> Digital 6 (PWM)
 * 	  Pin 5 of dust sensor          -> Ground
 * Datasheet: http://www.samyoungsnc.com/products/3-1%20Specification%20DSM501.pdf
* Contributor: epierre
**/

// Enable debug prints
#define MY_DEBUG

// Enable and select radio type attached
#define MY_RADIO_RF24
//#define MY_RADIO_NRF5_ESB
//#define MY_RADIO_RFM69
//#define MY_RADIO_RFM95

#include <MySensors.h>

#define CHILD_ID_DUST_PM10            0
#define CHILD_ID_DUST_PM25            1
#define DUST_SENSOR_DIGITAL_PIN_PM10  6
#define DUST_SENSOR_DIGITAL_PIN_PM25  3

uint32_t SLEEP_TIME = 30*1000; // Sleep time between reads (in milliseconds)
//VARIABLES
int val = 0;           // variable to store the value coming from the sensor
float valDUSTPM25 =0.0;
float lastDUSTPM25 =0.0;
float valDUSTPM10 =0.0;
float lastDUSTPM10 =0.0;
uint32_t duration;
uint32_t starttime;
uint32_t endtime;
uint32_t sampletime_ms = 30000;
uint32_t lowpulseoccupancy = 0;
float ratio = 0;
long concentrationPM25 = 0;
long concentrationPM10 = 0;

MyMessage dustMsgPM10(CHILD_ID_DUST_PM10, V_LEVEL);
MyMessage msgPM10(CHILD_ID_DUST_PM10, V_UNIT_PREFIX);
MyMessage dustMsgPM25(CHILD_ID_DUST_PM25, V_LEVEL);
MyMessage msgPM25(CHILD_ID_DUST_PM25, V_UNIT_PREFIX);

void setup()
{
	pinMode(DUST_SENSOR_DIGITAL_PIN_PM10,INPUT);
	pinMode(DUST_SENSOR_DIGITAL_PIN_PM25,INPUT);
}

void presentation()
{
	// Send the sketch version information to the gateway and Controller
	sendSketchInfo("Dust Sensor DSM501", "1.4");

	// Register all sensors to gateway (they will be created as child devices)
	present(CHILD_ID_DUST_PM10, S_DUST);
	send(msgPM10.set("ppm"));
	present(CHILD_ID_DUST_PM25, S_DUST);
	send(msgPM25.set("ppm"));
}

void loop()
{

	//get PM 2.5 density of particles over 2.5 µm.
	concentrationPM25=(long)getPM(DUST_SENSOR_DIGITAL_PIN_PM25);
	Serial.print("PM25: ");
	Serial.println(concentrationPM25);
	Serial.print("\n");

	if ((concentrationPM25 != lastDUSTPM25)&&(concentrationPM25>0)) {
		send(dustMsgPM25.set((int32_t)ceil(concentrationPM25)));
		lastDUSTPM25 = ceil(concentrationPM25);
	}

	//get PM 1.0 - density of particles over 1 µm.
	concentrationPM10=getPM(DUST_SENSOR_DIGITAL_PIN_PM10);
	Serial.print("PM10: ");
	Serial.println(concentrationPM10);
	Serial.print("\n");
	//ppmv=mg/m3 * (0.08205*Tmp)/Molecular_mass
	//0.08205   = Universal gas constant in atm·m3/(kmol·K)
	int temp=20; //external temperature, if you can replace this with a DHT11 or better
	long ppmv=(concentrationPM10*0.0283168/100/1000) *  (0.08205*temp)/0.01;

	if ((ceil(concentrationPM10) != lastDUSTPM10)&&((long)concentrationPM10>0)) {
		send(dustMsgPM10.set((int32_t)ppmv));
		lastDUSTPM10 = ceil(concentrationPM10);
	}

	//sleep to save on radio
	sleep(SLEEP_TIME);

}


long getPM(int DUST_SENSOR_DIGITAL_PIN)
{

	starttime = millis();

	while (1) {

		duration = pulseIn(DUST_SENSOR_DIGITAL_PIN, LOW);
		lowpulseoccupancy += duration;
		endtime = millis();

		if ((endtime-starttime) > sampletime_ms) {
			ratio = (lowpulseoccupancy-endtime+starttime)/(sampletime_ms*10.0);  // Integer percentage 0=>100
			long concentration = 1.1*pow(ratio,3)-3.8*pow(ratio,2)+520*ratio+0.62; // using spec sheet curve
			//Serial.print("lowpulseoccupancy:");
			//Serial.print(lowpulseoccupancy);
			//Serial.print("\n");
			//Serial.print("ratio:");
			//Serial.print(ratio);
			//Serial.print("\n");
			//Serial.print("DSM501A:");
			//Serial.println(concentration);
			//Serial.print("\n");

			lowpulseoccupancy = 0;
			return(concentration);
		}
	}
}