ESP8266 IoT Sensor Data Publisher

This Arduino project showcases an ESP8266-based IoT sensor data publisher. It reads temperature and humidity data from a DHT11 sensor and controls lights through Adafruit IO MQTT. The code supports multi-WiFi configuration, ensuring robust connectivity.

Hardware Requirements

• ESP8266-based board (e.g., NodeMCU, Wemos D1 Mini, etc.)
• DHT11 temperature and humidity sensor
• Two-channel relay module

Configuration

config.h

Configure WiFi and Adafruit IO MQTT parameters in this file:

• Relay1, Relay2: GPIO pins for relays.
• DHTPIN: GPIO pin for the DHT11 sensor.
• WiFi credentials for three networks.
• Adafruit IO MQTT broker details.

main.ino

The main sketch sets up connections, subscribes to Adafruit IO feeds for relay control, and publishes sensor data.

Usage

1. Update configurations in config.h.
2. Connect relay module and DHT11 sensor to GPIO pins.
3. Upload the code to your ESP8266 board.
4. Board connects to WiFi networks and Adafruit IO MQTT.
5. Subscribe to Adafruit IO feeds for relay control.
6. Publish temperature and humidity data.
7. Monitor and control relays remotely via Adafruit IO.

Flowchart

flowchart LR
    start[Start] --> config[Config.h]
    config --> library[Include Libraries]
    library --> define[Define Pin Output]
    define --> dht[Define DHT Module]
    dht --> wifi[Wifi Config]
    wifi --> wifi1[Wifi 1]
    wifi --> wifi2[Wifi 2]
    wifi --> wifi3[Wifi 3]
    wifi1 --> connected1[Connected to Wifi 1]
    wifi2 --> connected2[Connected to Wifi 2]
    wifi3 --> connected3[Connected to Wifi 3]
    connected1 --> server1[Start Server]
    connected2 --> server2[Start Server]
    connected3 --> server3[Start Server]
    server1 --> handleRoot1[Handle Root Request]
    server2 --> handleRoot2[Handle Root Request]
    server3 --> handleRoot3[Handle Root Request]
    handleRoot1 --> html1[WiFi Credentials Form]
    handleRoot2 --> html2[WiFi Credentials Form]
    handleRoot3 --> html3[WiFi Credentials Form]
    html1 --> processCred1[Process WiFi Credentials]
    html2 --> processCred2[Process WiFi Credentials]
    html3 --> processCred3[Process WiFi Credentials]
    processCred1 --> connect1[Connect to WiFi]
    processCred2 --> connect2[Connect to WiFi]
    processCred3 --> connect3[Connect to WiFi]
    connect1 --> mqtt[MQTT Connection]
    connect2 --> mqtt
    connect3 --> mqtt
    mqtt --> subscribe1[Subscribe to Light1]
    mqtt --> subscribe2[Subscribe to Light2]
    subscribe1 --> controlRelay1[Control Relay1 Light1]
    subscribe2 --> controlRelay2[Control Relay2 Light2]
    controlRelay1 --> a[End]
    controlRelay2 --> a
    a --> loop[Loop]

    loop --> dhtRead[Read DHT Sensors]
    dhtRead --> publishTemp[Publish Temperature]
    dhtRead --> publishHumi[Publish Humidity]
    publishTemp --> checkTemp[Check Publish Status]
    publishHumi --> checkHumi[Check Publish Status]
    checkTemp --> checkEnd[End]
    checkHumi --> checkEnd
    checkEnd --> delay[Delay]
    delay --> mqttRead[Read MQTT Messages]
    mqttRead --> checkSub1[Check Subscribe Light1]
    mqttRead --> checkSub2[Check Subscribe Light2]
    checkSub1 --> updateRelay1[Update Relay1]
    checkSub2 --> updateRelay2[Update Relay2]
    updateRelay1 --> loop
    updateRelay2 --> loop

style start fill:#8BC34A,stroke:#4CAF50
style a fill:#FF5722,stroke:#F44336
style wifi1, wifi2, wifi3, connected1, connected2, connected3, server1, server2, server3, handleRoot1, handleRoot2, handleRoot3, html1, html2, html3, processCred1, processCred2, processCred3, connect1, connect2, connect3, mqtt, subscribe1, subscribe2, controlRelay1, controlRelay2, loop, dhtRead, publishTemp, publishHumi, checkTemp, checkHumi, checkEnd, delay, mqttRead, checkSub1, checkSub2, updateRelay1, updateRelay2 stroke:#333,stroke-width:2px

Note

• Ensure a stable internet connection and access to Adafruit IO for MQTT.
• Double-check hardware connections and GPIO assignments.

Credits

This project utilizes the following libraries:

• ESP8266WiFi
• ESP8266WiFiMulti
• Adafruit_MQTT
• Adafruit_MQTT_Client
• DHT