Arduino code for periodically publishing temperature and humidity measurements to an MQTT broker.
- Arduino-compatible board with WiFi connectivity. For this project, I used the FeatherS3 development board
- BME280 Temperature, Humidity, and Pressure Sensor. Adafruit offers a breakout board which easily connects to the STEMMA QT connector on the FeatherS3 board
- STEMMA QT cable
- Lithium Polymer Battery with JST connector
The following libraries should be added to the Arduino IDE using the library manager.
Create a file called "secrets.h" and set the following constants. Note that "secrets.h" is ignored in the .gitignore file to avoid accidentally checking it in.
- WIFI_SSID - the SSID of the WiFi network to connect to.
- WIFI_PASSWORD - the password for the WiFi network.
- MQTT_CLIENT_ID - the client ID for connecting to the MQTT broker.
- MQTT_BROKER - the hostname or IP address (e.g.,
IPAddress(192, 168, 1, 1)) of the MQTT broker. - TEMP_TOPIC - the name of the topic to publish temperature messages.
- HUMIDITY_TOPIC - the name of the topic to publish humidity messages.
- LOOP_DELAY - integer representing the delay in milliseconds at the end of loop().
After opening the serial monitor, you should see something similar to the following if everything works as expected:
Initializing BME280 sensor...OK
Connecting to Wi-Fi.....OK
Connecting to MQTT broker...OK
PUBLISH home/office/temperature - {"time":4043,"temperature":24.79000092} - OK
PUBLISH home/office/humidity - {"time":4045,"humidity":33.27246094} - OK
- Reconnect to WiFi and MQTT on disconnect
- Add username/password authentication for MQTT
- Add TLS support for MQTT