ESP32 Weather Station

An ESP32-based weather station that connects to Wi-Fi and an MQTT broker, collects environmental data (temperature, humidity, pressure, rainfall), and publishes the results as JSON.

It supports a BME280 sensor for temperature, humidity, and pressure, and a tipping bucket rain gauge for rainfall measurement. Boot information is stored in EEPROM for persistence across reboots.

See the Complete Documentation for more detail on installation and setup.

---

Features

• Connects to Wi-Fi with static IP configuration and auto-reconnect.
• Connects to an MQTT broker with auto-reconnect.
• Subscribes to an input MQTT topic and publishes sensor readings to an output MQTT topic.
• Collects data from:
  • BME280 (temperature, humidity, pressure).
  • Davis tipping bucket rain gauge (rainfall).
• Uses EEPROM to log:
  • Number of boots.
  • Last reboot reason.
• Includes reboot logic for invalid sensor readings or failed connections.

---

Hardware Requirements

• ESP32 development board.
• BME280 sensor (I²C).
• Davis tipping bucket rain gauge or compatible (connected to pin GPIO16).

---

Wiring

ESP32 ↔ BME280 (I²C)

ESP32 Pin	BME280 Pin
3.3V	VCC
GND	GND
GPIO21	SDA
GPIO22	SCL

ESP32 ↔ Rain Gauge

ESP32 Pin	Rain Gauge
GPIO16	Signal
3.3V	VCC
GND	GND

Note: Rain gauge uses an interrupt on GPIO16 to count bucket tips.

---

Software Requirements

• Arduino IDE or PlatformIO.
• ESP32 board support package.
• Arduino libraries:
  • WiFi.h
  • PubSubClient
  • Adafruit BME280
  • Adafruit Unified Sensor
  • EEPROM

---

Configuration

Update these variables in the code before flashing:

// Wi-Fi credentials
const char* ssid = "YOUR_WIFI_SSID";
const char* password = "YOUR_WIFI_PASSWORD";

// MQTT broker
const char* mqtt_server = "BROKER_IP_ADDRESS";

// Optional static IP config
IPAddress local_IP(192, 168, 1, 40);
IPAddress gateway(192, 168, 1, 1);
IPAddress subnet(255, 255, 255, 0);
IPAddress primaryDNS(8, 8, 8, 8);
IPAddress secondaryDNS(8, 8, 4, 4);

MQTT authentication (username/password) can also be updated in the connect_to_mqtt() function.

---

MQTT Topics

• Subscribe
  • esp32/in → triggers the device to take a reading and publish data.
• Publish
  • esp32/out → JSON payload containing temperature, pressure, humidity, and rainfall.
  • esp32/out/debug → Debug messages (boot count and reboot reasons).
  • esp32/out/keepalive → Periodic keep-alive signal.

Example Payload

{
  "temperature": 20.0,
  "pressure": 1000.0,
  "humidity": 50.0,
  "mm_rain": 1.2
}

---

EEPROM Usage

The EEPROM stores a small struct with:

• num_boots: number of boots since first flash.
• reason: the reason for the last reboot (e.g., Wi-Fi failure, MQTT failure, invalid sensor values).

---

Known Issues / TODO

• The setup_bme280() and get_bme_values() functions are stubbed; uncomment and configure wiring to enable live sensor data.
• Improve error handling for MQTT and Wi-Fi reconnection.
• Add OTA updates for field deployment.

---

Author

• Dane Lennon
  Initial version: 2022-11-22