BMP280 with Arduino Nano

Wiring for the GY-BMP280 pressure + temperature 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

BMP280 pin	Role	Arduino Nano pin	Notes
VCC	Power	3V3
GND	Ground	GND
SCL	I2C clock (SCL)	A5 (PC5)
SDA	I2C data (SDA)	A4 (PC4)
CSB	Not wired to the board	not connected	Chip select. Leave unconnected (pulled HIGH on the board) to use I2C
SDO	Not wired to the board	not connected	Address select: LOW = 0x76, HIGH = 0x77. Most boards default to 0x76

Check before you power it on

Supply: 3.3 V from the 3V3 pin.
The BMP280 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 0x58.

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-BMP280 pressure + temperature 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 BMP280?

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

Does the BMP280 work with the Arduino Nano at 5 V?

The BMP280 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 BMP280?

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

BoardPilot checks this wiring in 3D as you build it, and finds crossed or missing wires on the real board.

Download BoardPilot

Full Arduino Nano pinout · GY-BMP280 pressure + temperature: all pins and data

The BMP280 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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