airgradient_mqtt.ino

gistfile1.txt

/**
 * This sketch connects an AirGradient DIY sensor to a WiFi network, and sends
 * these metrics via MQTT. Adapted from original by Jeff Geerling.
 */

#include <AirGradient.h>
#include <ESP8266WiFi.h>
#include <WiFiClient.h>
#include <PubSubClient.h>

#include <Wire.h>
#include "SSD1306Wire.h"

AirGradient ag = AirGradient();

// Config ----------------------------------------------------------------------

// Optional.
const char* deviceId = "airgradient";

// Hardware options for AirGradient DIY sensor.
const bool hasPM = true;
const bool hasCO2 = true;
const bool hasSHT = true;

// WiFi and IP connection info.
const char* ssid = "";
const char* password = "";
const int port = 9926;

// MQTT connection info.
const char* mqtt_user = "airgradient";
const char* mqtt_pass = "";
const char* clientId = "airgradient";
const char* MQTTtopic = "airgradient";

// Uncomment the line below to configure a static IP address.
// #define staticip
#ifdef staticip
IPAddress static_ip(192, 168, 2, 15);
IPAddress gateway(192, 168, 2, 1);
IPAddress subnet(255, 255, 255, 0);
#endif

//The mqtt server
IPAddress server(192, 168, 2 ,13);

// The frequency of measurement updates.
const int updateFrequency = 5000;
// The frequency of mqtt messages;
const int MQTTFrequency = 60000;

// For housekeeping.
long lastUpdate = millis();
long lastMQTT = millis();
int counter = 0;
String payload = "";

// Config End ------------------------------------------------------------------

SSD1306Wire display(0x3c, SDA, SCL);
WiFiClient espClient;
PubSubClient client(server, 1883, espClient);



void reconnect() {
  // Loop until we're reconnected
  while (!client.connected()) {
    Serial.print("Attempting MQTT connection...");
    // Create a random client ID
    // Attempt to connect
    if (client.connect(clientId, mqtt_user, mqtt_pass)) {
      Serial.println("connected");
      // Once connected, publish an announcement...
      // client.publish(MQTTTopic, "Starting...");
    } else {
      Serial.print("failed, rc=");
      Serial.print(client.state());
      Serial.println(" try again in 5 seconds");
      // Wait 5 seconds before retrying
      yield();
      delay(5000);
    }
  }
}


void setup() {
  Serial.begin(57600);

  // Init Display.
  display.init();
  display.flipScreenVertically();
  showTextRectangle("Init", String(ESP.getChipId(),HEX),true);



  // Set static IP address if configured.
  #ifdef staticip
  WiFi.config(static_ip,gateway,subnet);
  #endif
  
  // Set WiFi mode to client (without this it may try to act as an AP).
  WiFi.mode(WIFI_STA);

  // Configure Hostname
  if ((deviceId != NULL) && (deviceId[0] == '\0')) {
    Serial.printf("No Device ID is Defined, Defaulting to board defaults");
  }
  else {
    // wifi_station_set_hostname(deviceId); # 'wifi_station_set_hostname' was not declared in this scope

    WiFi.hostname(deviceId);
  }
  
  // Setup and wait for WiFi.
  WiFi.begin(ssid, password);
  Serial.println("");
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    showTextRectangle("Trying to", "connect...", true);
    Serial.print(".");
  }

  // Enable enabled sensors.
  if (hasPM) ag.PMS_Init();
  if (hasCO2) ag.CO2_Init();
  if (hasSHT) ag.TMP_RH_Init(0x44);

  Serial.println("");
  Serial.print("Connected to ");
  Serial.println(ssid);
  Serial.print("IP address: ");
  Serial.println(WiFi.localIP());
  Serial.print("MAC address: ");
  Serial.println(WiFi.macAddress());
  Serial.print("Hostname: ");
  Serial.println(WiFi.hostname());

  client.setServer(server, 1883);
}

void loop() {
  long t = millis();

  updateScreen(t);
  
  payload = GenerateMetrics();
  Serial.println("");
  Serial.println("payload: ");
  Serial.print(payload);
  if (!client.connected()) {
    reconnect();
  }
  
  sendMQTT(t, payload);
  
}


String GenerateMetrics() {
  String message = "{\"id\":\"" + String(deviceId) + "\",\"mac\":\"" + WiFi.macAddress().c_str() + "\"";

  if (hasPM) {
    int stat = ag.getPM2_Raw();

    // pm02 Particulate Matter PM2.5 value
    message += ",\"pm02\":" + String(stat);
  }

  if (hasCO2) {
    int stat = ag.getCO2_Raw();
    //rco2 CO2 value, in ppm
    message += ",\"rco2\":" + String(stat);
  }

  if (hasSHT) {
    TMP_RH stat = ag.periodicFetchData();

    //atmp Temperature, in degrees Celsius";
    message += ",\"atmp\":" + String(stat.t);

    //Relative humidity, in percent";
    message += ",\"rhum\":" + String(stat.rh);
  }
  message += "\}";

  return message;
}


// DISPLAY
void showTextRectangle(String ln1, String ln2, boolean small) {
  display.clear();
  display.setTextAlignment(TEXT_ALIGN_LEFT);
  if (small) {
    display.setFont(ArialMT_Plain_16);
  } else {
    display.setFont(ArialMT_Plain_24);
  }
  display.drawString(32, 16, ln1);
  display.drawString(32, 36, ln2);
  display.display();
}

void updateScreen(long now) {
  if ((now - lastUpdate) > updateFrequency) {
    // Take a measurement at a fixed interval.
    switch (counter) {
      case 0:
        if (hasPM) {
          int stat = ag.getPM2_Raw();
          showTextRectangle("PM2",String(stat),false);
        }
        break;
      case 1:
        if (hasCO2) {
          int stat = ag.getCO2_Raw();
          showTextRectangle("CO2", String(stat), false);
        }
        break;
      case 2:
        if (hasSHT) {
          TMP_RH stat = ag.periodicFetchData();
          showTextRectangle("TMP", String(stat.t, 1) + "C", false);
        }
        break;
      case 3:
        if (hasSHT) {
          TMP_RH stat = ag.periodicFetchData();
          showTextRectangle("HUM", String(stat.rh) + "%", false);
        }
        break;
    }
    counter++;
    if (counter > 3) counter = 0;
    lastUpdate = millis();
  }
}


void sendMQTT(long now, String payload) {
  // send out the MQTT message.
  if ((now - lastMQTT) > MQTTFrequency) {
    int succ = false;
    int attempts = 10;
    while (succ == false && attempts-- > 0) {
        succ = client.publish(MQTTtopic, payload.c_str());
        Serial.print('Sending: ');
        Serial.println(succ);
        yield();
        delay(500);
    lastMQTT = millis();
    }
  }
}