This code provides a simple implementation of an MQTT-based relay control system using an ESP8266 board (such as NodeMCU). It connects to the Adafruit IO MQTT server and allows you to control a relay remotely through the Adafruit IO platform or a physical button connected to the board.
translation:
Before running this code, make sure you have the following:
- An ESP8266-based board (e.g., NodeMCU) with the necessary firmware installed.
- Arduino IDE with the ESP8266 board package installed.
- An Adafruit IO account.
- Wi-Fi network credentials (SSID and password).
Connect the following components to your ESP8266 board:
- Connect a push button to pin D2 (GPIO 2) of the board. This button will be used to control the relay locally.
- Connect a relay module to pin D3 (GPIO 3) of the board. This relay will control the electrical device you want to switch on/off.
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Install the necessary libraries:
- Adafruit MQTT Library: Install it from the Arduino Library Manager (Sketch -> Include Library -> Manage Libraries) by searching for "Adafruit MQTT Library" and clicking "Install".
- Adafruit MQTT Client Library: Install it from the Arduino Library Manager by searching for "Adafruit MQTT Client" and clicking "Install".
- ESP8266WiFi Library: Install it from the Arduino Library Manager by searching for "ESP8266WiFi" and clicking "Install".
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Open the Arduino IDE and create a new sketch.
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Copy and paste the provided code into the sketch.
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Update the following constants with your Wi-Fi and Adafruit IO credentials:
ssid: Set it to your Wi-Fi network SSID.password: Set it to your Wi-Fi network password.AIO_USERNAME: Set it to your Adafruit IO username.AIO_KEY: Set it to your Adafruit IO key.
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Upload the sketch to your ESP8266 board.
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Open the serial monitor (Tools -> Serial Monitor) to monitor the board's output.
Once the code is uploaded to your ESP8266 board, it will connect to your Wi-Fi network and Adafruit IO MQTT server.
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Go to the Adafruit IO website and log in to your account.
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Create a new feed called "relay" in your Adafruit IO dashboard.
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To control the relay remotely, navigate to your "relay" feed and send MQTT messages with the payload
1to turn the relay on or0to turn it off.
Press the push button connected to the D2 pin of the ESP8266 board to toggle the state of the relay.
The serial monitor will display the current status of the relay (ON or OFF) and indicate successful or failed publishing to Adafruit IO.
graph TD
A[Start] --> B[Initialize libraries and credentials]
B --> C[Set up button and relay pins]
C --> D[Connect to Wi-Fi and Adafruit IO MQTT server]
D --> E[Set initial relay state to off]
E --> F[Enter main loop]
F --> G[Process incoming MQTT packets]
G --> H[Read button state]
H --> I[Publish button state to Adafruit IO]
I --> F
G --> J[If new MQTT message received for relay feed]
J --> K[Update relay state]
K --> L[If relay state is '1']
L --> M[Turn on relay]
M --> N[Print 'Relay ON']
L --> O[If relay state is '0']
O --> P[Turn off relay]
P --> Q[Print 'Relay OFF']
J --> R[Publish current relay state to Adafruit IO]
R --> S[If publishing successful]
S --> T[Print 'Published to Adafruit IO']
R --> U[If publishing fails]
U --> V[Print 'Publishing failed']
R --> F
- If the ESP8266 fails to connect to your Wi-Fi network, ensure that you have entered the correct SSID and password.
- Check your Adafruit IO credentials (username and key) to ensure they are correct.
- Verify the wiring connections between the ESP8266 board, button, and relay.
- Make sure you have a stable internet connection.
This code serves as a basic example and may require modifications to suit your specific requirements. Refer to the official documentation of the libraries used for more advanced usage and functionality.
This code is based on the Adafruit IO Arduino library examples and modified for this specific relay control application.