It's easy to use the L3GD20 sensor with Python or CircuitPython and the Adafruit CircuitPython L3GD20 module. This module allows you to easily write Python code that reads the angular momentum from the sensor.
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 L3GD20 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 M0 to the sensor with I2C:
And an example of a Feather M0 wired with hardware SPI:
- Board 3V to sensor Vin
- Board GND to sensor GND
- Board SCK to sensor SCL
- Board MOSI to sensor SDA
- Board MISO to sensor SA0
- Board D5 to sensor CS (or use any other free 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 to see whether your platform is supported.
Here's the Raspberry Pi wired with I2C:
And an example on the Raspberry Pi 3 Model B wired with SPI:
- Pi 3V3 to sensor Vin
- Pi GND to sensor GND
- Pi MOSI to sensor SDA
- Pi MISO to sensor SA0
- Pi SCLK to sensor SCL
- Pi #5 to sensor CS (or use any other free GPIO pin)
CircuitPython Installation of L3GD20 Library
You'll need to install the Adafruit CircuitPython L3GD20 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.
For non-express boards like the Trinket M0 or Gemma M0, you'll need to manually install the necessary libraries from the bundle:
- adafruit_l3gd20.mpy
- adafruit_bus_device
Before continuing make sure your board's lib folder or root filesystem has the adafruit_l3gd20.mpy, and adafruit_bus_device files and folders copied over.
Next connect to the board's serial REPL so you are at the CircuitPython >>> prompt.
Python Installation of L3GD20 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-l3gd20
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 angular momentum values from the board's 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:
import time import board import busio import adafruit_l3gd20 I2C = busio.I2C(board.SCL, board.SDA) SENSOR = adafruit_l3gd20.L3GD20_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 busio import digitalio import adafruit_l3gd20 CS = digitalio.DigitalInOut(board.D5) SPIB = busio.SPI(board.SCK, board.MOSI, board.MISO) SENSOR = adafruit_l3gd20.L3GD20_SPI(SPIB, CS)
Now you're ready to read values from the sensor using any of these properties:
- gyro - The x, y, z angular momentum tuple floats, rescaled appropriately for range selected.
For example to print angular momentum:
print('Angular momentum (rad/s): {}'.format(SENSOR.gyro))
That's all there is to using the L3GD20 sensor with CircuitPython!
# SPDX-FileCopyrightText: 2021 ladyada for Adafruit Industries
# SPDX-License-Identifier: MIT
import time
import board
import adafruit_l3gd20
# Hardware 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
# Initializes L3GD20 object using default range, 250dps
SENSOR = adafruit_l3gd20.L3GD20_I2C(I2C)
# Initialize L3GD20 object using a custom range and output data rate (ODR).
# SENSOR = adafruit_l3gd20.L3GD20_I2C(
# I2C, rng=adafruit_l3gd20.L3DS20_RANGE_500DPS, rate=adafruit_l3gd20.L3DS20_RATE_200HZ
# )
# Possible values for rng are:
# adafruit_l3gd20.L3DS20_Range_250DPS, 250 degrees per second. Default range
# adafruit_l3gd20.L3DS20_Range_500DPS, 500 degrees per second
# adafruit_l3gd20.L3DS20_Range_2000DPS, 2000 degrees per second
# Possible values for rate are:
# adafruit_l3gd20.L3DS20_RATE_100HZ, 100Hz data rate. Default data rate
# adafruit_l3gd20.L3DS20_RATE_200HZ, 200Hz data rate
# adafruit_l3gd20.L3DS20_RATE_400HZ, 400Hz data rate
# adafruit_l3gd20.L3DS20_RATE_800HZ, 800Hz data rate
# Hardware SPI setup:
# import digitalio
# CS = digitalio.DigitalInOut(board.D5)
# SPIB = board.SPI()
# SENSOR = adafruit_l3gd20.L3GD20_SPI(SPIB, CS)
# SENSOR = adafruit_l3gd20.L3GD20_I2C(
# SPIB,
# CS,
# rng=adafruit_l3gd20.L3DS20_RANGE_500DPS,
# rate=adafruit_l3gd20.L3DS20_RATE_200HZ,
# )
while True:
print("Angular Velocity (rad/s): {}".format(SENSOR.gyro))
print()
time.sleep(1)
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