Adafruit BME280 Temp/Humidity/Pressure

Name: Adafruit BME280 Temp/Humidity/Pressure
Brand: Adafruit
Availability: InStock

AdafruitArduino, Feather M0, Raspberry Pi

The Adafruit BME280 is an environmental sensor for temperature, humidity, and pressure with support for I2C and SPI interfaces.

Manufacturer guide / datasheet

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Specifications

Operating Voltage: 3-5VDC (Vin) / 3.3V (3Vo)
Logic Level: 3-5V
Dimensions: STEMMA QT form factor
Connectivity: I2C, SPI

Pinout

Pin	Name	Functions	Notes
Vin	Power	POWER	3-5VDC input
3Vo	3.3V Output	—	Up to 100mA available
GND	Ground	GND
SCK	SPI Clock	SPI
SDO	Serial Data Out	SPI
SDI	Serial Data In	SPI
CS	Chip Select	SPI

Interactive pinout

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Arduino, Feather M0, Raspberry Pi

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Starter code

Community starter examples — minimal, unofficial, and provided to get you wiring fast. Verify against the manufacturer datasheet before relying on them.

Arduino (C++)

Arduino library: Adafruit BME280 Library (+ Adafruit Unified Sensor)

arduino

// BME280 temp/humidity/pressure over I2C — community starter example
#include <Wire.h>
#include <Adafruit_BME280.h>

Adafruit_BME280 bme;  // I2C

void setup() {
  Serial.begin(115200);
  Wire.begin();                 // Uno: A4=SDA A5=SCL | ESP32: GPIO21/GPIO22
  if (!bme.begin(0x77)) {       // many generic clones use 0x76
    Serial.println("BME280 not found");
    while (1) delay(10);
  }
}

void loop() {
  Serial.print("T="); Serial.print(bme.readTemperature()); Serial.print(" C  ");
  Serial.print("RH="); Serial.print(bme.readHumidity()); Serial.print(" %  ");
  Serial.print("P="); Serial.print(bme.readPressure() / 100.0F); Serial.println(" hPa");
  delay(1000);
}

MicroPython

MicroPython library: bme280 (robert-hh/BME280)

python

# BME280 over I2C (ESP32) — community starter example
# lib: robert-hh/BME280 (copy bme280.py onto the board)
from machine import Pin, I2C
import bme280, time

i2c = I2C(0, scl=Pin(22), sda=Pin(21))   # ESP32 default I2C pins
sensor = bme280.BME280(i2c=i2c)          # auto-detects 0x76 / 0x77

while True:
    print(sensor.values)                  # (temperature, pressure, humidity)
    time.sleep(1)

Wiring

Pin	Arduino Uno R3	ESP32 DevKitC (WROOM-32)	Notes
VIN	+5V	3V3	Onboard regulator + level shifting: 3-5 V safe
GND	GND	GND
SCK	A5/SCL	GPIO22	I2C clock (SCL) on this breakout
SDI	A4/SDA	GPIO21	I2C data (SDA) on this breakout

Typical uses

Weather stations and indoor climate logging
Altitude estimation from barometric pressure