It's easy to use the LIS331 sensors with Python or CircuitPython, and the Adafruit CircuitPython LIS331 module. This module allows you to easily write Python code that reads acceleration from the either LIS331HH or H3LIS331 sensors.

You can use this sensor with any CircuitPython microcontroller board or with a computer that has GPIO and Python thanks to Adafruit_Blinka, our CircuitPython-for-Python compatibility library.

CircuitPython Microcontroller Wiring

First wire up a LIS331 to your board exactly as shown on the previous pages for Arduino.  You can use either I2C or SPI wiring, although it's recommended to use I2C for simplicity.  Here's an example of wiring a Feather M4 to the sensor with I2C using one of the handy STEMMA QT connectors:

You can also use the standard 0.100" pitch headers to wire it up on a breadboard:

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 to see whether your platform is supported. 

Here's the Raspberry Pi wired to the sensor using I2C and a STEMMA QT connector:

You can also use the standard 0.100" pitch headers to wire it up on a breadboard:

CircuitPython Installation of LIS331 Library

You'll need to install the Adafruit CircuitPython LIS331 library on your CircuitPython board.

First make sure you are running the latest version of Adafruit CircuitPython for your board.

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.  Our CircuitPython starter guide has a great page on how to install the library bundle.

Before continuing make sure your board's lib folder or root filesystem has the adafruit_lis331.mpy, adafruit_bus_device, and adafruit_register files and folders copied over.

Next connect to the board's serial REPL so you are at the CircuitPython >>> prompt.

Python Installation of LIS331 Library

You'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!

Once that's done, from your command line run the following command:

• sudo pip3 install adafruit-circuitpython-lis331

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 acceleration measurements from the board's Python REPL.

Run the following code to import the necessary modules and initialize the I2C connection with the sensor:

import time
import board
import adafruit_lis331

i2c = board.I2C()
# uncomment this line and comment out the one after if using the H3LIS331
# lis = adafruit_lis331.H3LIS331(i2c)
lis = adafruit_lis331.LIS331HH(i2c)

import time
import board
import adafruit_lis331

i2c = board.I2C()
# uncomment this line and comment out the one after if using the H3LIS331
# lis = adafruit_lis331.H3LIS331(i2c)
lis = adafruit_lis331.LIS331HH(i2c)

Now you're ready to read values from the sensor using these properties:

• acceleration - The x, y, z acceleration values returned in a 3-tuple and are in m / s ^ 2..

For example to print the acceleration values for all three axes:

That's all it takes to get measuring acceleration using the LIS331 accelerometer breakouts!

Full Example Code

# SPDX-FileCopyrightText: 2021 ladyada for Adafruit Industries
# SPDX-License-Identifier: MIT

import time
import board
import adafruit_lis331

i2c = board.I2C()  # uses board.SCL and board.SDA
# i2c = board.STEMMA_I2C()  # For using the built-in STEMMA QT connector on a microcontroller
lis = adafruit_lis331.LIS331HH(i2c)

while True:
    print("Acceleration : X: %.2f, Y:%.2f, Z:%.2f ms^2" % lis.acceleration)
    time.sleep(0.1)

# SPDX-FileCopyrightText: 2021 ladyada for Adafruit Industries
# SPDX-License-Identifier: MIT

import time
import board
import adafruit_lis331

i2c = board.I2C()  # uses board.SCL and board.SDA
# i2c = board.STEMMA_I2C()  # For using the built-in STEMMA QT connector on a microcontroller
lis = adafruit_lis331.LIS331HH(i2c)

while True:
    print("Acceleration : X: %.2f, Y:%.2f, Z:%.2f ms^2" % lis.acceleration)
    time.sleep(0.1)