CodeCell: Reading Acceleration & Shaking Detection

CodeCell includes a BNO085 3-axis accelerometer that measures movement and orientation in space. In this guide, you’ll learn how to read acceleration values and detect shaking — triggering the onboard LED whenever motion is detected.

How It Works

An accelerometer measures changes in speed and direction (acceleration) across three axes:

• X-axis → Left and right
• Y-axis → Forward and backward
• Z-axis → Up and down (gravity)

Even when still, CodeCell feels gravity, the Z-axis will show about 9.81 m/s², Earth’s gravitational acceleration.

To start reading motion data, initialize and call:

myCodeCell.Init(MOTION_ACCELEROMETER);          // Enable accelerometer
myCodeCell.Motion_AccelerometerRead(x, y, z);   // Read acceleration values

Example 1 – Read Real-Time Motion

This example prints live acceleration data for each axis. Try moving or tilting CodeCell to see how values change.

#include <CodeCell.h>

CodeCell myCodeCell;
float x = 0.0, y = 0.0, z = 0.0;

void setup() {
  Serial.begin(115200);
  myCodeCell.Init(MOTION_ACCELEROMETER);  // Initialize accelerometer
}

void loop() {
  if (myCodeCell.Run(10)) {               // Run loop at 10 Hz
    myCodeCell.Motion_AccelerometerRead(x, y, z);

    Serial.print("X: "); Serial.print(x);
    Serial.print("  Y: "); Serial.print(y);
    Serial.print("  Z: "); Serial.println(z);
  }
}

Example 2 – Detect Shaking

This example calculates total acceleration and turns the LED red when CodeCell is shaken above a set threshold.

#include <CodeCell.h>
#include <math.h>  // For sqrt()

CodeCell myCodeCell;
float x = 0.0, y = 0.0, z = 0.0;

const float SHAKE_THRESHOLD = 15.0;  // Adjust for sensitivity

void setup() {
  Serial.begin(115200);
  myCodeCell.Init(MOTION_ACCELEROMETER);  // Enable accelerometer
}

void loop() {
  if (myCodeCell.Run(10)) {               // Run at 10 Hz
    myCodeCell.Motion_AccelerometerRead(x, y, z);

    // Calculate total acceleration magnitude
    float totalAcceleration = sqrt(x * x + y * y + z * z);
    Serial.print("Total Acceleration: ");
    Serial.println(totalAcceleration);

    if (totalAcceleration > SHAKE_THRESHOLD) {
      Serial.println("Shake detected!");
      myCodeCell.LED(255, 0, 0);          // Red LED for shake
      delay(500);
    }
  }
}

By combining all three axes into a single totalAcceleration value, you can easily detect shakes in any direction. If it exceeds 15.0 m/s², the onboard LED lights up red for 0.5 seconds.

Customization Tips

• Change LED behavior: Use color or brightness to indicate motion strength.
• Detect tilts or knocks: Use X/Y/Z thresholds to create gesture-based actions.
• Track movement: Attach CodeCell to a wearable to measure motion patterns.