GY-BMP280-3.3 Pressure Sensor Module Arduino Tutorial and Pinout

GY-BMP280-3.3 high precision atmospheric pressure sensor module for Arduino – tutorial on first use and testing of the module as well as GY-BMP280-3.3 pressure sensor module pinout. The same module is sold under different names such as BMP280-3.3 or just BMP280, although BMP280 is the actual pressure sensor chip that can be seen just below the capacitor at the top of the module, as shown in the image below.

GY-BMP280-3.3 Pressure Sensor Module

GY-BMP280-3.3 Pressure Sensor Module

GY-BMP280-3.3 Pressure Sensor Module Basic Information

The least you need to know before using this module is presented below.

What the GY-BMP280-3.3 Pressure Sensor Module Can Measure

It can measure both atmospheric pressure and temperature. Because it can measure atmospheric pressure, it can be used to calculate altitude.

BMP280 Datasheet

The module uses a BMP280 barometric pressure sensor from Bosch. A datasheet on the BMP280 can be found on the BMP280 page on the Bosch website. This datasheet and web page is for the actual BMP280 device found on the GY-BMP280-3.3 module.

Operating Voltage

The GY-BMP280-3.3 operates from 3.3V, so requires 3.3V power and must be driven with 3.3V logic levels. Some modules that use the BMP280 device have a voltage regulator and level shifters so that it can be operated from a 5V controller such as an Arduino Uno. This module does not have any regulator or level shifters.

From the BMP280 datasheet:
Minimum power supply voltage – 1.71V
Maximum power supply voltage – 3.6V
Absolute maximum power supply voltage – 4.25V

Direct connection to a 3.3V Arduino such as an Arduino Due, Arduino Zero, Arduino M0 or Arduino M0 Pro is fine, so long as the pressure sensor is powered from the Arduino 3.3V pin. For 5V Arduinos such as the Arduino Uno or Arduino MEGA, it must be powered from the Arduino 3.3V pin, and must be interface to the Arduino using a level shifter for the data and clock pins.

I have seen videos on YouTube where this module is connected directly to a 5V Arduino and powered from 5V. This is extremely bad engineering practice and could result in severely damaging or destroying the BMP280 device. It is sheer luck if the device actually works and does not blow up.


I2C or SPI can be used to interface or connect the module to an Arduino or other microcontroller. Pin 6 of the module controls the I2C address of the module which can be set to either 0x76 when pin 6 is left unconnected or 0x77 when pin 6 is pulled to Vcc (3.3V).

Wrong Information

The Internet is full of wrong information regarding this sensor module. Tutorials on powering this device from 5V and not using level shifters on the data pins are out there. Or if the advice is to power the module from 3.3V, then the data pins are directly connected to 5V Arduino pins without level shifters.

Another mistake that I have seen is that people do not know that the I2C address can be changed by using pin 6 of the module, as can be seen in the pinout for the module (link in the section below). What they then do is modify the Arduino driver to change its I2C address so that it matches the default I2C address of the module, instead of just pulling pin 6 high so that the module address matches the driver address.

GY-BMP280-3.3 Pressure Sensor Module Pinout

Refer to the GY-BMP280-3.3 pressure sensor module pinout page for the module’s pinout and circuit diagram.

GY-BMP280-3.3 Pressure Sensor Module Tutorial

A tutorial on basic use and testing of the GY-BMP280-3.3 pressure sensor module on the Starting Electronics website shows how to connect the module to both 3.3V and 5V Arduino boards. An Arduino Due is used to demonstrate how to wire the module to a 3.3V Arduino. For 5V Arduino boards, an Arduino Uno is used to demonstrate how to use a transistor level shifter to wire the module for 5V use.

The tutorial also shows how to install drivers for the pressure sensor module and then test the module to make sure that it can read pressure and temperature.

Go to the tutorial now →

ESP8266 ESP-05 WiFi Module – Getting Started

I recently purchased three ESP8266 ESP-05 WiFi modules. These are very cheap WiFi modules costing around $4 USD each, so are ideal for hobbyists, makers and hackers to use in various projects. My idea was to try to get an Arduino web server working on WiFi as a cheap alternative to using an Ethernet shield or WiFi shield.

Although the same module is available from several suppliers, the particular module that I bought was from SainSmart: SainSmart Neu ESP8266 Esp-05 Remote Serial Port WIFI Transceiver Wireless Module AP+STA

ESP8266 ESP-05 WiFi Module

ESP8266 ESP-05 WiFi Module

ESP8266 ESP-05 Pinout and Documentation

The supplier web page for the ESP8266 ESP-05 had no pinout for the module and no documentation. Some of the information on the web page for the module was also completely wrong, for example they state that the module has 5V compatible I/O, however this is wrong. The I/O pins only work with 3.3V logic and are not 5V tolerant.

They also state “on board antennae”, but this module does not have an on board antennae, it has a connector for an external antennae.

ESP8266 ESP-05 Pinout

After some searching on the web I found a pinout diagram for the 5 pin version of the ESP8266 ESP-05. A new article with pinout and power requirements for the ESP-05 is now available on the Starting Electronics website.

ESP8266 Documentation

The manufacturer of the ESP8266EX chip found on the ESP-05 and other modules is the Espressif company. Documentation for the module must be taken from the ESP8266EX datasheets on the Espressif website. Look under Documentation on the ESP8266 resource page where you will find datasheets, user guides, application notes, technical references, etc.

Getting Started with the ESP8266 ESP-05 WiFi Module

You bought a ESP8266 5-pin ESP-05 module, now what? Here are the steps necessary to get the module working for the first time. Once you have a basic understanding of the module and where to find further information you will be able to start your own project development.

Soldering the Header

The module comes with a separate 5-pin header that must be soldered into the module. After the header is soldered to the module it is easy to use the module in a breadboard.

ESP8266 ESP-05 with Header Soldered

ESP8266 ESP-05 with Header Soldered

The following video shows how to solder the header to the module.


Aerial / Antennae

I found that the module works fine without an aerial / antennae as long as it is near enough to the WiFi router that it is connecting to. Connecting a wire to the aerial connector does give it more range and picks up the second WiFi router that I have on the other side of the house.

Testing the Module

Use the pinout diagram to correctly connect the ESP8266 module power and UART data pins. An Arduino Due is ideal for testing the module. This is because a Due can supply enough current from its 3.3V pin and works with 3.3V logic. The Arduino Due is therefore completely compatible with the ESP8266 module.

The article on testing the ESP8266 ESP-05 module using an Arduino Due shows how to connect the ESP8266 module to the Due and test it. Use this article to get started with sending AT commands to the WiFi module.

Documentation and Staring your Own Projects

Once you have the ESP8266 module working, it is a matter of sending the correct AT commands to the module to set it up for your project.

Find example AT commands in the ESP8266 AT Command Examples document.

Find all of the AT commands in the ESP8266 Instruction Set document.