Autonomous Indoor Air-Quality Remediation Drone

// main.cpp
#include "Particle.h"
#include "CCS811.h"        // https://github.com/sparkfun/SparkFun_CCS811_Arduino_Library
#include "PMS.h"           // https://github.com/fuho/PMS

// --- Pin assignments (change as needed) ---
#define PIN_HEPA_MODULE   D6
#define PIN_OZONE_MODULE  D7

// CCS811 VOC sensor (I2C on default Wire/BUS)
CCS811 ccs811;

// PMS5003 (UART2 on TX/RX)
PMS pms(Serial1);
PMS::DATA pmsData;

// Grid mapping parameters
const int GRID_ROWS = 3;
const int GRID_COLS = 3;
int currentRow = 0;
int currentCol = 0;

// Timing
unsigned long lastSensorRead = 0;
const unsigned long SENSOR_INTERVAL = 5000; // 5s

// Cloud variables & functions
double latestVOC = 0;
double latestPM25 = 0;
int latestAction = 0; // 0 = none, 1 = HEPA, 2 = Ozone

// Remote override
int remoteCommand = 0; // 0:auto, 1:HEPA, 2:Ozone, 3:off
int cmdHandler(String cmd) {
  int c = cmd.toInt();
  if (c >= 0 && c <= 3) remoteCommand = c;
  return remoteCommand;
}

void setup() {
  // Particle cloud setup
  Particle.variable("VOC", latestVOC);
  Particle.variable("PM25", latestPM25);
  Particle.variable("Action", latestAction);
  Particle.function("SetModule", cmdHandler);

  // Module outputs
  pinMode(PIN_HEPA_MODULE, OUTPUT);
  pinMode(PIN_OZONE_MODULE, OUTPUT);
  digitalWrite(PIN_HEPA_MODULE, LOW);
  digitalWrite(PIN_OZONE_MODULE, LOW);

  // Start serial for PMS5003
  Serial1.begin(9600);

  // Init CCS811
  Wire.begin();
  if (!ccs811.begin()) {
    Serial.println("CCS811 not found");
    Particle.publish("Error", "CCS811 init failed", PRIVATE);
  }
  ccs811.setDriveMode(CCS811_DRIVE_MODE_1SEC);
}

void loop() {
  unsigned long now = millis();
  if (now - lastSensorRead >= SENSOR_INTERVAL) {
    lastSensorRead = now;
    readAndProcessSensors();
    advanceGridPosition();
  }
}

// Read sensors, decide action, publish to cloud
void readAndProcessSensors() {
  // --- VOC reading ---
  if (ccs811.dataAvailable()) {
    ccs811.readAlgorithmResults();
    latestVOC = ccs811.geteCO2();      // equivalent CO2 in ppm
    double tvoc = ccs811.getTVOC();    // total VOC in ppb
    LOG(TRACE, "VOC: %0.1f ppm, TVOC: %0.1f ppb", latestVOC, tvoc);
  }

  // --- Particulate reading ---
  pms.read(pmsData);
  latestPM25 = pmsData.PM_AE_UG_2_5;   // PM2.5 concentration (µg/m³)
  LOG(TRACE, "PM2.5: %0.1f ug/m3", latestPM25);

  // --- Decide action (simple threshold) ---
  int action = 0;
  if (remoteCommand == 0) {
    // automatic mode
    if (latestPM25 > 35.0)      action = 1;  // HEPA
    else if (latestVOC > 1000)  action = 2;  // Ozone
    else                         action = 0;  // none
  } else {
    // remote override
    action = remoteCommand;
  }
  applyAction(action);

  // --- Publish to cloud ---
  latestAction = action;
  Particle.publish("GridPos", String::format("%d,%d", currentRow, currentCol), PRIVATE);
  Particle.publish("AQData", String::format("V%.0f_P%.1f_A%d", latestVOC, latestPM25, action), PRIVATE);
}

// Turn modules on/off
void applyAction(int action) {
  switch (action) {
    case 1: // HEPA
      digitalWrite(PIN_HEPA_MODULE, HIGH);
      digitalWrite(PIN_OZONE_MODULE, LOW);
      break;
    case 2: // Ozone
      digitalWrite(PIN_HEPA_MODULE, LOW);
      digitalWrite(PIN_OZONE_MODULE, HIGH);
      break;
    default: // off
      digitalWrite(PIN_HEPA_MODULE, LOW);
      digitalWrite(PIN_OZONE_MODULE, LOW);
      break;
  }
}

// Simple zig-zag grid mover—replace with your SLAM or waypoint logic
void advanceGridPosition() {
  currentCol++;
  if (currentCol >= GRID_COLS) {
    currentCol = 0;
    currentRow = (currentRow + 1) % GRID_ROWS;
  }
}