BME280 with Arduino Nano

Wiring for the GY-BME280 breakout on the Arduino Nano (ATmega328P, 5 V logic), chosen with the same pin rules BoardPilot uses: default buses first, and no pins that are used for flash, USB, the debugger or booting.

Wiring

Check before you power it on

• Supply: 3.3 V from the 3V3 pin.
• The BME280 is a 3.3 V part and the Arduino Nano uses 5 V signals. Power it from 3.3 V and put a level shifter on the signal wires, or buy a 5 V version of the module.
• I2C uses the board’s default pins A4 (SDA) and A5 (SCL). Most modules include pull-up resistors; if the part is not found, check them and swap-test SDA/SCL.
• To make sure it is the real chip, read register 0xD0: a genuine part answers 0x60.

Test code (Arduino)

#include <Wire.h>

void setup() {
  Serial.begin(115200);
  Wire.begin();  // SDA = A4, SCL = A5 (the board's default I2C pins)
  Wire.beginTransmission(0x76);
  bool found = Wire.endTransmission() == 0;
  Serial.println(found ? "GY-BME280 breakout found at 0x76" : "Not found: check power, GND and SDA/SCL");
}

void loop() {}

Arduino board: arduino:avr:nano. Clones with the old bootloader upload at 57600 baud: choose “ATmega328P (Old Bootloader)” if uploads fail.

Questions

Which Arduino Nano pins do I use for the BME280?

VIN → 3V3, GND → GND, SCL → A5 (PC5), SDA → A4 (PC4).

Does the BME280 work with the Arduino Nano at 5 V?

The BME280 is a 3.3 V part and the Arduino Nano uses 5 V signals. Power it from 3.3 V and put a level shifter on the signal wires, or buy a 5 V version of the module.

What is the I2C address of the BME280?

0x76 or 0x77. An I2C scan (BoardPilot does it for you) shows which one your module uses.

Full Arduino Nano pinout · GY-BME280 breakout: all pins and data

The BME280 on other boards

ESP32 DevKit Arduino Mega 2560 R3 Arduino Uno R3 WeAct Black Pill STM32F411CE ESP32-C3-DevKitM-1 ESP32-S3-DevKitC-1 Nordic nRF52840 DK NUCLEO-F401RE Raspberry Pi Pico 2 Raspberry Pi Pico W Raspberry Pi Pico Teensy 4.1

Other parts on the Arduino Nano

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