ESP32 BME280 Environmental Monitor

This guide will walk you through building a low-power ESP32-based environmental monitor using a BME280 sensor. The device uses deep sleep mode to conserve power, waking up at set intervals to collect a full set of environmental data and send it to your Telemetry Harbor instance for visualization and analysis.

Repo Link: https://github.com/TelemetryHarbor/harbor-esp32-bme280

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Hardware Requirements

Component	Description	Approximate Cost
ESP32	Development board (NodeMCU ESP32, WROOM, etc.)	$3.82 (AliExpress) / $9.90 (Amazon US)
BME280	Temperature, humidity, and pressure sensor module	$4.20 (AliExpress) / $8.99 (Amazon US)
Jumper wires	For connecting components	$0.42 (AliExpress) / $5.49 (Amazon US)
Micro USB cable	For power & programming	$3.00 (AliExpress) / $5.00 (Amazon US)
Battery	For long-term standalone, low-power deployment	(Cost varies)

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Software Requirements

• Arduino IDE (1.8.13 or newer) or PlatformIO
• ESP32 board support package
• Required libraries:
  • Adafruit BME280 Library
  • Adafruit Unified Sensor
  • Telemetry Harbor SDK (available via Library Manager)
  • WiFi Library (built into ESP32 core)
• Telemetry Harbor account (free tier available)

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Wiring Diagram

Connect the BME280 sensor to the ESP32 using I2C:

BME280 Pin	ESP32 Pin	Function
VCC	3.3V	Power
GND	GND	Ground
SDA	GPIO 21	Data
SCL	GPIO 22	Clock

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Setup

1. Hardware Assembly

1. Connect the BME280 sensor to the ESP32 according to the wiring diagram.
2. Connect the ESP32 to your computer via USB.

2. Software Setup

1. Install the Arduino IDE.
2. Add ESP32 board support by adding this URL in Preferences > Additional Boards Manager URLs:

   https://raw.githubusercontent.com/espressif/arduino-esp32/gh-pages/package_esp32_index.json

3. Install the required libraries via the Library Manager:
   • Adafruit BME280 Library
   • Adafruit Unified Sensor
   • Telemetry Harbor SDK (Search for "TelemetryHarborSDK")

3. Telemetry Harbor Configuration

1. Create a Telemetry Harbor account.
2. Create a new Harbor called "ESP32_Environmental_Monitor" (or your preferred name).
3. Select "General" harbor type and "Free" specification.
4. Copy your API ENDPOINT and API Key from the Harbor details page.

4. Configure and Upload the Code

1. Open the ESP32_BME280_Telemetry.ino file in the Arduino IDE.
2. Update the following variables at the top of the file:
   • WiFi SSID and password
   • Telemetry Harbor API Endpoint URL and API Key
   • Adjust the shipId to your desired name (e.g., "Living Room").
3. Select your ESP32 board model from Tools > Board.
4. Select the correct COM port from Tools > Port.
5. Upload the code.

5. Visualize Your Data

1. Access your Telemetry Harbor account.
2. Navigate to the Harbor details page and copy your Grafana password.
3. Access the Grafana dashboard using the provided endpoint.
4. Log in with your Telemetry Harbor email and the Grafana password.
5. Navigate to Dashboards and select the Comprehensive Telemetry Dashboard to see your data.

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Customization

Sleep Interval

To change how frequently the ESP32 wakes up and sends data, modify the SLEEP_INTERVAL_SEC variable in the code. The default is 5 minutes (300 seconds).

const int SLEEP_INTERVAL_SEC = 5 * 60; // 5 minutes

Sensor Calibration

You can adjust the sensor offsets for more accurate readings.

const float TEMP_OFFSET = 0.0;     // Adjust temperature by degrees Celsius
const float HUMIDITY_OFFSET = 0.0; // Adjust humidity by percentage
const float PRESSURE_OFFSET = 0.0; // Adjust pressure by hPa

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Troubleshooting

Common Issues

• BME280 not found: Double-check your wiring or try the alternate I2C address (0x76 or 0x77).
• WiFi connection failure: Verify your credentials. The device will automatically go back to sleep if it can't connect, so wait for the next wakeup cycle.
• Data not appearing in Telemetry Harbor: Verify your API key and API Endpoint URL are correct.

Debug Mode

The new code has minimal serial output to save power. All of the core logic runs within the setup() function before the device goes to sleep. The loop() function is empty. To debug, add Serial.println() statements within the setup() function before the esp_deep_sleep_start() call. Monitor the serial output at 115200 baud.