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Tasmota BME280 Environmental Sensor Station

Build a WiFi environmental monitoring station with BME280 sensor measuring temperature, humidity, and barometric pressure. Uses I2C on any ESP8266/ESP32 with Tasmota. Under $6 total cost.

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Boards:ESP8266ESP32ESP32-C3
Firmware:Tasmota
Use Cases:Environmental MonitoringWeather StationHome AutomationIndoor Climate
GitHubBlog Post

Tasmota BME280 Environmental Sensor Station

Build an ultra-cheap WiFi environmental sensor station that measures temperature, humidity, and barometric pressure using a BME280 sensor connected via I2C to an ESP8266 or ESP32 running Tasmota.

Why This Project

  • Three sensors in one — temperature, humidity, and pressure from a single chip
  • Ultra-cheap — under $6 total with an ESP-01S
  • High accuracy — ±1°C, ±3% RH, ±1 hPa
  • I2C interface — only 4 wires needed
  • Auto-detected by Tasmota — no custom compilation required

Components Required

Component Purpose Est. Cost
ESP8266 board (ESP-01S or Wemos D1 Mini) WiFi microcontroller $2-4
GY-BME280 breakout board Temp + humidity + pressure sensor $2-3
Jumper wires (female-female) I2C connections $0.50

Total cost: ~$5.50

Wiring (I2C)

BME280           ESP8266 (D1 Mini)      ESP-01S
──────           ─────────────────      ───────
VCC          →   3.3V                   3.3V
GND          →   GND                    GND
SDA          →   GPIO4 (D2)            GPIO1 (TX)
SCL          →   GPIO5 (D1)            GPIO3 (RX)

Warning: Connect VCC to 3.3V only, not 5V. Using 5V causes self-heating and inaccurate temperature readings.

Tasmota Setup

  1. Flash tasmota-sensors.bin (ESP8266) or tasmota32 (ESP32)
  2. Go to Configuration → Configure Module
  3. Assign GPIOs to I2C SDA and I2C SCL
  4. Reboot — BME280 is auto-detected at address 0x76
  5. Dashboard shows live temperature, humidity, and pressure

Advanced Configuration

# Calibrate temperature offset
TempOffset -1.5

# Set telemetry period (seconds)
TelePeriod 60

# Use two BME280 sensors (change SDO pin to VCC for 0x77)
# First sensor at 0x76, second at 0x77

ESP-01S Build (Ultra-Compact)

The ESP-01S is the cheapest option at ~$1.50. Since it only has GPIO0, GPIO1 (TX), GPIO2, and GPIO3 (RX), you must use TX/RX as I2C pins:

  • SDA → GPIO1 (TX pin)
  • SCL → GPIO3 (RX pin)

Flash using a USB-to-ESP-01 adapter (CP2104 recommended). After flashing, the serial pins are repurposed for I2C.

Detailed guide: cgomesu.com — DIY Tasmota BME280

Home Assistant Integration

Auto-discovered via MQTT. Creates three sensor entities:

  • sensor.tasmota_bme280_temperature
  • sensor.tasmota_bme280_humidity
  • sensor.tasmota_bme280_pressure

Compatible Boards

  • ESP-01S — cheapest, most compact ($1.50)
  • Wemos D1 Mini — best for prototyping
  • NodeMCU — most GPIOs available
  • Any ESP32 board — more memory for additional sensors

Resources

Blog Post

Project writeup & details

GitHub Repository

Source code & project files