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ADXL343 / ADXL345

Works with

Any CircuitPython board with I2C or SPI

What it does

The ADXL343 and ADXL345 are triple-axis accelerometers with a configurable range of ±2g to ±16g. They are older parts that appear frequently in existing projects and tutorials, making them worth knowing even though newer sensors like the LIS3DH offer similar capabilities. Like the LIS3DH, these sensors include hardware tap detection and freefall detection. The ADXL345 adds a higher output data rate option compared to the ADXL343. Both chips share the same CircuitPython library.

Installing the library

Copy adafruit_adxl34x.mpy from the Adafruit CircuitPython Bundle to your board's lib/ folder. Also copy adafruit_bus_device/ if it is not already present.

Quick start

import board
import busio
import adafruit_adxl34x

i2c = busio.I2C(board.SCL, board.SDA)
sensor = adafruit_adxl34x.ADXL343(i2c)

x, y, z = sensor.acceleration
print(x, y, z)  # m/s²

Key things you can do

What you want How to do it
Read acceleration (m/s²) sensor.acceleration → (x, y, z) tuple
Enable tap detection sensor.enable_tap_detection(tap_count=1, threshold=20, duration=50, latency=20, window=255)
Check for a tap event sensor.events["tap"]
Enable freefall detection sensor.enable_freefall_detection(threshold=10, time=25)
Check for freefall event sensor.events["freefall"]
Set measurement range sensor.range = adafruit_adxl34x.Range.RANGE_4_G

Reading the official docs

https://docs.circuitpython.org/projects/adxl34x/en/latest/

The events dictionary is the primary way to check tap and freefall status — reading a key clears the event flag, so each event is only reported once. The docs include default parameter values for enable_tap_detection() and enable_freefall_detection() so you can start with those and tune from there.

Projects using this library