Adafruit BMP388 and BMP390 - Precision
Barometric Pressure and Altimeter
Created by Kattni Rembor

https://learn.adafruit.com/adafruit-bmp388-bmp390-bmp3xx

Last updated on 2024-06-03 02:42:14 PM EDT©Adafruit Industries

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Table of Contents
Overview

3

Pinouts

6• Power Pins
• SPI Logic pins
• I2C Logic pins
• Address Jumper

Assembly

9• Prepare the header strip:• Add the breakout board:• And Solder!

Arduino12• I2C Wiring• SPI Wiring• Download Adafruit_BMP3XX library• Load Demo
• Example Code

Arduino Docs

19

Python & CircuitPython

19• CircuitPython Microcontroller Wiring• Python Computer Wiring• CircuitPython Installation of BMP3XX Library• Python Installation of BMP3XX Library• CircuitPython & Python Usage• Full Example CodePython Docs

28

WipperSnapper

29• What is WipperSnapper• Wiring• Usage

Downloads

36• Files• Schematic and Fab Print for BMP390• Schematic and Fab Print for BMP388 STEMMA QT Version• Schematic and Fab Print for BMP388 Original Version• 3D Model of BMP390• 3D Model of BMP388 QT©Adafruit Industries

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Overview

Bosch has been a leader in barometric pressure sensors, from the BMP085 (http://
adafru.it/391). BMP180 (http://adafru.it/1603), and BMP280 (http://adafru.it/2651)... now
we've got the next generation, the Adafruit BMP388 and BMP390 Precision
Barometric Pressure sensors. As you would expect, this sensor is similar to its earlier
versions but even better. The BMP3xx has better precision than the BMP2xx series
which makes it excellent for environmental sensing or as a precision altimeter. It caneven be used in either I2C and SPI configurations.
The BMP3xx is the next-generation of sensors from Bosch, and is the upgrade to the
BMP280 - with a low altitude noise as low as 0.1m and the same fast conversion time.
And like the previous BMP280, you can use I2C or SPI. For simple easy wiring, gowith I2C. If you want to connect a bunch of sensors without worrying about I2C
address collisions, go with SPI.

©Adafruit Industries

Page 3 of 40• This BMP388 sensor has a relative accuracy of 8 Pascals, which translates toabout ± 0.5 meter of altitude• This BMP390 sensor has a relative accuracy of 3 Pascals, which translates toabout ± 0.25 meter of altitude
Compare to the BMP280's 12 Pascal/ ±1 meter!
The datasheet sort of implies they intend this sensor to be used for drones andquadcopters, to keep altitude stable, but you could also use this for wearables or any
project that wants to track height-above-sea-level. Note that for absolute height you'll
still need to enter in the barometric pressure at sea level, if the weather changes, but
that's true of every altimeter sensor that uses pressure. You can also measuretemperature with ±0.5°C accuracy.

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Nice sensor right? So we made it easy for you to get right into your next project. The
surface-mount sensor is soldered onto a PCB and comes with a 3.3V regulator andlevel shifting so you can use it with a 3V or 5V logic microcontroller without worry.

We also made these boards in the STEMMA QT form factor (https://adafru.it/LBQ),
making them easy to interface with. The STEMMA QT connectors (https://adafru.it/
JqB) on either side are compatible with the SparkFun Qwiic (https://adafru.it/Fpw) I2C
connectors. This allows you to make solderless connections between yourdevelopment board and the BMP390 or to chain it with a wide range of other sensors
and accessories using a compatible cable (https://adafru.it/JnB).

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There are two versions of this board - the STEMMA QT version shown above, andthe original header-only version shown below. Code works the same on both!

Pinouts©Adafruit Industries

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The BMP388 and BMP390 have the same exact pinout even though the names
are a little different!

Power Pins
• Vin - this is the power pin. Since the sensor chip uses 3 VDC, we have included
a voltage regulator on board that will take 3-5VDC and safely convert it down.
To power the board, give it the same power as the logic level of yourmicrocontroller - e.g. for a 5V micro like Arduino, use 5V• 3Vo - this is the 3.3V output from the voltage regulator, you can grab up to
100mA from this if you like
• GND - common ground for power and logic

SPI Logic pins
All pins going into the breakout have level shifting circuitry to make them 3-5V logic
level safe. Use whatever logic level is on Vin!
• SCK - This is the SPI Clock pin, its an input to the chip and can use 3 - 5V logic.

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• SDO - this is the Serial Data Out / Microcontroller In Sensor Out pin, for data
sent from the BMP3xx to your processor. Logic level is 3.3V output, so can beread by 5V microcontrollers.
• SDA - this is the Serial Data In / Microcontroller Out Sensor In pin, for data sentfrom your processor to the BMP3xx. Its an input to the chip and can use 3 - 5V
logic. (SDI on original version)• CS - this is the Chip Select pin, drop it low to start an SPI transaction. Its an input
to the chip and can use 3 - 5V logic.
• INT - this is the Interrupt pin. The BMP3xx can send an output signal to tell you
when data is read (we don't use this in our libraries but it is available for youruse). The logic level is 3.3V output, so it can be read by 5V microcontrollers.
If you want to connect multiple BMP3xx sensors to one microcontroller, have themshare the SDI, SDO and SCK pins. Then assign each one a unique CS pin.

I2C Logic pins
• SCK - this is also the I2C clock pin, connect to your microcontroller's I2C clockline.
• SDA - this is also the I2C data pin, connect to your microcontroller's I2C dataline. (SDI on original version)• STEMMA QT (https://adafru.it/Ft4) - These connectors allow you to connectors
to dev boards with STEMMA QT connectors or to other things with various
associated accessories (https://adafru.it/Ft6)
Leave the CS and SDO pins disconnected for I2C use.

Address Jumper• ADDR - This is the I2C address selection jumper. The default I2C address - when
this jumper is disconnected - is 0x77. On the STEMMA QT Versions you canchange the I2C address by shorting this jumper. Once shorted the I2C address
is 0x76.
Only the versions of these boards with STEMMA QT connectors have the ADDR
jumper©Adafruit Industries

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Assembly
The BMP388 and BMP390 have the same soldering technique even though thenames and shapes are a little different!

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Prepare the header strip:

Cut the strip to length if necessary. It will
be easier to solder if you insert it into a
breadboard - long pins down

Add the breakout board:

Place the breakout board over the pins sothat the short pins poke through the
breakout pads

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And Solder!

Be sure to solder all 8 pins for reliable
electrical contact.
(For tips on soldering, be sure to check out
our Guide to Excellent Soldering (https://
adafru.it/aTk)).

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You're done! Check your solder joints
visually and continue onto the next steps.

ArduinoYou can easily wire this breakout to any microcontroller, we'll be using an Arduino
Uno/328P compatible. For another kind of microcontroller, as long as you have 4
available pins it is possible to 'bit-bang SPI' or you can use two I2C pins, but usuallythose pins are fixed in hardware. Just check out the library, then port the code.

I2C Wiring
Use this wiring if you want to connect via I2C interface:©Adafruit Industries

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Connect Vin to the power supply, 3-5V isfine. (Red wire on STEMMA QT version.)
Use the same voltage that the
microcontroller logic is based off of. For
most older Arduinos, that is 5V.
Connect GND to common power/data
ground. (Black wire on STEMMA QT
version.)Connect the SCK/SCL pin to the I2C clock
SCL pin on your Arduino. (Yellow wire on
STEMMA QT version.) On an UNO & '328
based Arduino, this is also known as A5,
on a Mega it is also known as digital 21
and on a Leonardo/Micro, digital 3.
Connect the SDI/SDA pin to the I2C data
SDA pin on your Arduino. (Blue wire on
STEMMA QT version.) On an UNO & '328
based Arduino, this is also known as A4,
on a Mega it is also known as digital 20
and on a Leonardo/Micro, digital 2.

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SPI Wiring
Since this is a SPI-capable sensor, we can use hardware or 'software' SPI. To makewiring identical on all Arduinos, we'll begin with 'software' SPI. The following pins
should be used:©Adafruit Industries

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Connect Vin to the power supply, 3V or 5V
is fine. Use the same voltage that the
microcontroller logic is based off of. For
most Arduinos, that is 5V.
Connect GND to common power/data
ground.
Connect the SCK/SCL pin to Digital #13
but any pin can be used later.
Connect the SDO pin to Digital #12 but
any pin can be used later.
Connect the SDI/SDA pin to Digital #11 but
any pin can be used later.
Connect the CS pin Digital #10 but any pin
can be used later.

Later on, once we get it working, we can adjust the library to use hardware SPI if you
desire, or change the pins assignments.

Download Adafruit_BMP3XX library
To begin reading sensor data, you will need to install the Adafruit_BMP3XX library(code on our github repository) (https://adafru.it/EdV). It is available from the Arduino
library manager so we recommend using that.

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From the IDE open up the library manager...

And type in adafruit bmp3xx to locate the library. Click Install

You'll also need to install the Adafruit Unified Sensor library

We also have a great tutorial on Arduino library installation at:
http://learn.adafruit.com/adafruit-all-about-arduino-libraries-install-use (https://
adafru.it/aYM)

Load Demo
Open up File -> Examples -> Adafruit_BMP3XX -> bmp3xx_simpletest and upload toyour Arduino wired up to the sensor.

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Depending on whether you are using I2C or SPI, change the pin names and commentor uncomment the following lines.
#define BMP_SCK 13#define BMP_MISO 12#define BMP_MOSI 11#define BMP_CS 10#define SEALEVELPRESSURE_HPA (1013.25)
Adafruit_BMP3XX bmp; // I2C//Adafruit_BMP3XX bmp(BMP_CS); // hardware SPI//Adafruit_BMP3XX bmp(BMP_CS, BMP_MOSI, BMP_MISO, BMP_SCK);// Software SPI

Once uploaded to your Arduino, open up the serial console at 115200 baud to see
data being printed out:

Temperature is calculated in degrees C, you can convert this to F by using the classic
F = C * 9/5 + 32 equation.
Pressure is returned in the SI units of Pascals. 100 Pascals = 1 hPa = 1 millibar. Often
times barometric pressure is reported in millibar or inches-mercury (Hg). For futurereference 1 pascal =0.000295333727 inches of mercury, or 1 inch Hg = 3386.39
Pascal. So if you take the Pascal value of say 100734 and divide by 3389.39 you'll get
29.72 inches-Hg.
You can also calculate Altitude. However, you can only really do a good accurate jobof calculating altitude if you know the hPa pressure at sea level for your location©Adafruit Industries

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and day! The sensor is quite precise but if you do not have the data updated for thecurrent day, then it can be difficult to get more accurate than 10 meters.
Pass in the current sea level pressure in hPa - so the value will be somewhere around~1000. You can also test with the generic 1013.25 value.

Example CodeThe following example code is part of the standard library. It illustrates how you canretrieve sensor data from the BMP388 for the temperature, pressure and approximate
altitude:/***************************************************************************
This is a library for the BMP3XX temperature & pressure sensor
Designed specifically to work with the Adafruit BMP388 Breakout----> http://www.adafruit.com/products/3966
These sensors use I2C or SPI to communicate, 2 or 4 pins are required
to interface.
Adafruit invests time and resources providing this open source code,
please support Adafruit and open-source hardware by purchasing products
from Adafruit!
Written by Limor Fried & Kevin Townsend for Adafruit Industries.
BSD license, all text above must be included in any redistribution***************************************************************************/#include <Wire.h>#include <SPI.h>#include <Adafruit_Sensor.h>#include "Adafruit_BMP3XX.h"#define BMP_SCK 13#define BMP_MISO 12#define BMP_MOSI 11#define BMP_CS 10#define SEALEVELPRESSURE_HPA (1013.25)
Adafruit_BMP3XX bmp;
void setup() {Serial.begin(115200);
while (!Serial);
Serial.println("Adafruit BMP388 / BMP390 test");if (!bmp.begin_I2C()) {// hardware I2C mode, can pass in address & alt Wire//if (! bmp.begin_SPI(BMP_CS)) { // hardware SPI mode//if (! bmp.begin_SPI(BMP_CS, BMP_SCK, BMP_MISO, BMP_MOSI)) { // software SPI
mode
Serial.println("Could not find a valid BMP3 sensor, check wiring!");while (1);}// Set up oversampling and filter initialization
bmp.setTemperatureOversampling(BMP3_OVERSAMPLING_8X);
bmp.setPressureOversampling(BMP3_OVERSAMPLING_4X);
bmp.setIIRFilterCoeff(BMP3_IIR_FILTER_COEFF_3);
bmp.setOutputDataRate(BMP3_ODR_50_HZ);©Adafruit Industries

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}void loop() {if (! bmp.performReading()) {Serial.println("Failed to perform reading :(");
return;}Serial.print("Temperature = ");Serial.print(bmp.temperature);
Serial.println(" *C");
Serial.print("Pressure = ");Serial.print(bmp.pressure / 100.0);
Serial.println(" hPa");
Serial.print("Approx. Altitude = ");Serial.print(bmp.readAltitude(SEALEVELPRESSURE_HPA));
Serial.println(" m");Serial.println();delay(2000);}

Arduino Docs
Arduino Docs (https://adafru.it/EqL)

Python & CircuitPython
It's easy to use the BMP388 sensor with CircuitPython and the Adafruit CircuitPython
BMP3XX (https://adafru.it/Ei6) module. This module allows you to easily write Python
code that reads the barometric pressure, temperature and more from the sensor.
You can use this sensor with any CircuitPython microcontroller board or with acomputer that has GPIO and Python thanks to Adafruit_Blinka, our CircuitPython-forPython compatibility library (https://adafru.it/BSN).

CircuitPython Microcontroller Wiring
First wire up a BMP3xx to your board as shown below. You can use either I2C or SPI
wiring, although it's recommended to use I2C for simplicity. Here's an example ofwiring a Feather to the sensor with I2C:

©Adafruit Industries

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Board 3V to sensor VIN (red wire on
STEMMA QT version)
Board GND to sensor GND (black wire on
STEMMA QT version)
Board SCL to sensor SCK/SCL (yellow
wire on STEMMA QT version)
Board SDA to sensor SDI/SDA (blue wire
on STEMMA QT version)©Adafruit Industries

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And an example of a Feather wired with hardware SPI:

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Board 3V to sensor VIN
Board GND to sensor GND
Board SCK to sensor SCK/SCL
Board MOSI to sensor SDI/SDA
Board MISO to sensor SDO
Board D5 to sensor CS (or use any otherfree digital I/O pin)

Python Computer Wiring
Since there's dozens of Linux computers/boards you can use, we will show wiring for
Raspberry Pi. For other platforms, please visit the guide for CircuitPython on Linux tosee whether your platform is supported (https://adafru.it/BSN).
Here's the Raspberry Pi wired with I2C:

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Pi 3V3 to sensor VIN
Pi GND to sensor GND
Pi SCL to sensor SCK/SCL
Pi SDA to sensor SDI/SDA©Adafruit Industries

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And an example on the Raspberry Pi 3 Model B wired with SPI:

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Pi 3V3 to sensor VIN
Pi GND to sensor GND
Pi MOSI to sensor SDI/SDA
Pi MISO to sensor SDO
Pi SCLK to sensor SCK/SCL
Pi #5 to sensor CS (or use any other free
GPIO pin)

CircuitPython Installation of BMP3XX LibraryYou'll need to install the Adafruit CircuitPython BMP3XX (https://adafru.it/Ei6) libraryon your CircuitPython board.
First make sure you are running the latest version of Adafruit CircuitPython (https://
adafru.it/Amd) for your board.

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Next you'll need to install the necessary libraries to use the hardware--carefully follow
the steps to find and install these libraries from Adafruit's CircuitPython library
bundle (https://adafru.it/uap). Our CircuitPython starter guide has a great page on
how to install the library bundle (https://adafru.it/ABU).
For non-express boards like the Trinket M0 or Gemma M0, you'll need to manually
install the necessary libraries from the bundle:• adafruit_bmp3xx.mpy• adafruit_bus_device
Before continuing, make sure your board's lib folder or root filesystem has
the adafruit_bmp3xx.mpy, and adafruit_bus_device files and folders copied over.
Next connect to the board's serial REPL (https://adafru.it/Awz)so you are at theCircuitPython >>> prompt.

Python Installation of BMP3XX LibraryYou'll need to install the Adafruit_Blinka library that provides the CircuitPython
support in Python. This may also require enabling I2C on your platform and verifying
you are running Python 3. Since each platform is a little different, and Linux changes
often, please visit the CircuitPython on Linux guide to get your computer
ready (https://adafru.it/BSN)!
Once that's done, from your command line run the following command:• sudo pip3 install adafruit-circuitpython-bmp3xx
If your default Python is version 3 you may need to run 'pip' instead. Just make sure
you aren't trying to use CircuitPython on Python 2.x, it isn't supported!

CircuitPython & Python Usage
To demonstrate the usage of the sensor, we'll initialize it and read the pressure,temperature and more from the Python REPL.
If you're using an I2C connection, run the following code to import the necessary
modules and initialize the I2C connection with the sensor:©Adafruit Industries

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import time
import board
import adafruit_bmp3xx
i2c = board.I2C()
bmp = adafruit_bmp3xx.BMP3XX_I2C(i2c)

Or if you're using a SPI connection run this code instead to setup the SPI connection
and sensor:
import time
import board
import adafruit_bmp3xx
import digitalio
spi = board.SPI()
cs = digitalio.DigitalInOut(board.D5)
bmp = adafruit_bmp3xx.BMP3XX_SPI(spi, cs)

Now you're ready to read values from the sensor using any of these properties:• temperature - The sensor temperature in degrees Celsius.
• pressure - The pressure in hPa.
• altitude - The altitude in meters.
For example to print temperature and pressure:print("Pressure: {:6.1f}".format(bmp.pressure))
print("Temperature: {:5.2f}".format(bmp.temperature))

For altitude, you'll want to set the pressure at sea level for your location to get themost accurate measurement (remember these sensors can only infer altitude basedon pressure and need a set calibration point). Look at your local weather report for apressure at sea level reading and set the sea_level_pressure property:
bmp.sea_level_pressure = 1013.25

Then read the altitude property for a more accurate altitude reading (butremember this altitude will fluctuate based on atmospheric pressure changes!):
print('Altitude: {} meters'.format(bmp.altitude))©Adafruit Industries

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That's all there is to using the BMP388 sensor with CircuitPython!

Full Example Code# SPDX-FileCopyrightText: 2021 ladyada for Adafruit Industries# SPDX-License-Identifier: MIT
import time
import board
import adafruit_bmp3xx# I2C setup
i2c = board.I2C() # uses board.SCL and board.SDA# i2c = board.STEMMA_I2C() # For using the built-in STEMMA QT connector on a
microcontroller
bmp = adafruit_bmp3xx.BMP3XX_I2C(i2c)# SPI setup# from digitalio import DigitalInOut, Direction# spi = board.SPI()# cs = DigitalInOut(board.D5)# bmp = adafruit_bmp3xx.BMP3XX_SPI(spi, cs)
bmp.pressure_oversampling = 8
bmp.temperature_oversampling = 2
while True:
print("Pressure: {:6.4f}
bmp.temperature))
time.sleep(1)Temperature: {:5.2f}".format(bmp.pressure,Python Docs
Python Docs (https://adafru.it/EfI)©Adafruit Industries

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WipperSnapper

What is WipperSnapper
WipperSnapper is a firmware designed to turn any WiFi-capable board into an
Internet-of-Things device without programming a single line of code. WipperSnapper
connects to Adafruit IO (https://adafru.it/fsU), a web platform designed (byAdafruit! (https://adafru.it/Bo5)) to display, respond, and interact with your project's
data.
Simply load the WipperSnapper firmware onto your board, add credentials, and plug it
into power. Your board will automatically register itself with your Adafruit IO account.
From there, you can add components to your board such as buttons, switches,
potentiometers, sensors, and more! Components are dynamically added to hardware,
so you can immediately start interacting, logging, and streaming the data yourprojects produce without writing code.
If you've never used WipperSnapper, click below to read through the quick start guide
before continuing.

Quickstart: Adafruit IO
WipperSnapper
https://adafru.it/Vfd©Adafruit Industries

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WiringFirst, wire up a BMP388 to your board exactly as follows. Here is an example of the
BMP388 wired to an Adafruit ESP32 Feather V2 (http://adafru.it/5400) using I2C witha STEMMA QT cable (no soldering required) (http://adafru.it/4210)

Board 3V to sensor VIN (red wire on
STEMMA QT)Board GND to sensor GND (black wire on
STEMMA QT)Board SCL to sensor SCL (yellow wire on
STEMMA QT)Board SDA to sensor SDA (blue wire on
STEMMA QT)UsageConnect your board to Adafruit IO Wippersnapper and navigate to the
WipperSnapper board list (https://adafru.it/TAu).
On this page, select the WipperSnapper board you're using to be brought to theboard's interface page.

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If you do not see your board listed here - you need to connect your board to Adafruit
IO (https://adafru.it/Vfd) first.

On the device page, quickly check thatyou're running the latest version of the
WipperSnapper firmware.
The device tile on the left indicates theversion number of the firmware running on
the connected board.
If the firmware version is green with acheckmark - continue with this guide.
If the firmware version is red with an
exclamation mark "!" - update to the latest
WipperSnapper firmware (https://adafru.it/Vfd) on your board before continuing.

©Adafruit Industries

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Next, make sure the sensor is plugged into your board and click the I2C Scan button.

You should see the BMP388's default I2C address of 0x77 pop-up in the I2C scanlist.

I don't see the sensor's I2C address listed!
First, double-check the connection and/or wiring between the sensor and theboard.
Then, reset the board and let it re-connect to Adafruit IO WipperSnapper.
With the sensor detected in an I2C scan, you're ready to add the sensor to yourboard.
Click the New Component button or the + button to bring up the component picker.

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Adafruit IO supports a large amount of components. To quickly find your sensor,
type BMP3 into the search bar, then select the BMP388 or BMP390 component.

On the component configuration page, the BMP388's sensor address should be listed
along with the sensor's settings.
The Send Every option is specific to each sensor's measurements. This option will tellthe Feather how often it should read from the BMP388 sensor and send the data to
Adafruit IO. Measurements can range from every 30 seconds to every 24 hours.
For this example, set the Send Every interval to every 30 seconds.

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Your device interface should now show the sensor components you created. After theinterval you configured elapses, WipperSnapper will automatically read values fromthe sensor(s) and send them to Adafruit IO.

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To view the data that has been logged from the sensor, click on the graph next to thesensor name.

Here you can see the feed history and edit things about the feed such as the name,privacy, webhooks associated with the feed and more. If you want to learn more
about how feeds work, check out this page (https://adafru.it/10aZ).

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Downloads
Files• BMP388 datasheet (https://adafru.it/19hf)• BMP390 datasheet (https://adafru.it/Otb)• BMP388 STEMMA QT Fritzing object in the Adafruit Fritzing Library (https://
adafru.it/QEE)• BMP388 Original Version Fritzing object in the Adafruit Fritzing Library (https://
adafru.it/EfM)• BMP390 Fritzing object in the Adafruit Fritzing Library (https://adafru.it/Otc)• EagleCAD PCB files on GitHub (https://adafru.it/Otd)• 3D models for BMP388 QT (https://adafru.it/19hA)• 3D models for BMP390 QT (https://adafru.it/19hB)

Schematic and Fab Print for BMP390©Adafruit Industries

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Schematic and Fab Print for BMP388
STEMMA QT Version©Adafruit Industries

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Schematic and Fab Print for BMP388
Original Version©Adafruit Industries

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3D Model of BMP390©Adafruit Industries

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3D Model of BMP388 QT©Adafruit Industries

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