Accelerometer

Accelerometer

A MicroPython code example running on a Raspberry Pi Pico 2 W microcontroller connected to a 3-axis digital accelerometer module (ADXL345) and an OLED display module (SSD1306) on a breadboard to draw and rotate a 3D shape on the OLED display by rotating the accelerometer about its X and Y axes

An accelerometer measures acceleration around the x, y and z axis. In robotics, it is essential in determining the robot position and movement. In this script, we draw a 3D shape, and control its rotation using the accelerometer.

Create a new file in Thonny, with file name accelerometer.py. Copy and paste the code below into the file you created.

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print("\nAccelerometer")

# DESCRIPTION

# An accelerometer measures acceleration around the x, y and z axis. 
# In robotics, it is essential in determining the robot position and movement.
# In this script, we draw a 3D shape, and control its rotation using the accelerometer.

# CONNECTIONS REQUIRED

# Connect ADXL345 module using only the 4 pins on the right side
#   Pins: GND => GND, VCC => VCC, SDA => GP6, SCL => GP7

from machine import Pin, SoftI2C
from oled import OLED
from adxl345 import ADXL345
from cube import Cube
from math import atan2, sqrt, degrees

accel = ADXL345(SoftI2C(sda=Pin(6), scl=Pin(7)))
oled = OLED(scl_pin=15, sda_pin=14)
cube = Cube(scaleX=1, scaleY=1.4, scaleZ=0.2)

try:
    while True:
                
        # Calculate pitch (rotation around y-axis, 360 degrees)
        # and roll (rotaton around x-axis, 180 degrees)
        # using x, y and z from the accelerometer.
        # Yaw (rotation around vertical z-axis) needs
        # a different sensor, a magnetometer or a gyroscope.        
        x, y, z = accel.read()
        pitch = atan2(-x, sqrt(y*y + z*z))
        roll = atan2(y, z)
        
        cube.draw(display=oled.display, angleX=-degrees(roll), angleY=-degrees(pitch)) 

except KeyboardInterrupt:
    print("\nInterrupted by user!")

finally:
    oled.reset()