[Fitbit] #4 Accelerometer API, Device API Reference

Reference
Fitbit offers three types of APIs for building Fitbit device apps and clock faces.

Device API Reference
The Device APIs are accessbile by applications which run on Fitbit devies only.

Accelerometer API

Class: Accelerometer

An Accelerometer sensor measures a device’s acceleration along 3 orthogonal axes (x, y and z).

• The x axis is parallel with the device’s screen, aligned with the top and bottom edges, in the left-to-right direction.
• The y axis is parallel with the device’s screen, aligned with the left and right edges, in the bottom-to-top direction.
• The z axis is perpendicular to the device’s screen, pointing up.

Accelertaion readings include the acceleration of gravity. For example: If the device is at rest, lying flat on a table on the surface of the earth, the acceleration along the z axis should equal the acceleration of grivity (^~9.8 m/s²), and the accleration along the x and y axees should be 0.

Read the Accelerometer Sensor Guide for further information. The Accelerometer API provides access to the acceleration data measured by the hardware sensor.

app

import { Acceleromter } from "acceleromter";

if (Accelerometer) {
  console.log("This device has an Accelerometer!");
  const accelorometer = new Accelerometer({ frequency: 1 });
  accelerometer.addEventListener("reading", () => {
    console.log(`${accelerometer.x},${accelerometer.y},${accelerometer.z}`);
  });
} else {
  console.log("This device does NOT have an Accelerometer!");
}

Properties

readonly activated

boolean

Flag that indicates if the sensor is activate or not. When a sensor is created, the sensor is not activated, thus the initial value of this property equals false.

onactivate

((this: Sensor, event: Event) => any) or undefined

Event handler that is called when the sensor is activated.

onerror

((this: Sensor, event: SensorErrorEvent) => any) or undefined

Event handler that is called when an error occurs. When an error occurs, the sensor is automatically stopped, and the activated property equals false.

onreading

((this: Sensor, event: Event) => any) or undefined

Event handler that is called whenever a new reading is available.

readonly readings

BatchedAccelerometerReading or undefined

New in SDK 2.0

Interface: BatchedAccelerometerReading

New in SDK 2.0

Properties

readonly timestamp

Float32Array

readonly x

Float32Array

readonly y

Float32Array

readonly z

Float32Array

Interface: AccelerometerReading

Acceleration data measured by the accelerometer sensor.

Properties

readonly timestamp

number or null

Timestamp of the reading in milliseconds.

NOTE: this is relative to an unspecified arbitrary 0 time, or null if no reading is avilable (when the sensor is not yet activated and there are no valid cached values that can be used).

readonly x

number or null

readonly y

number or null

readonly z

number or null

Acceleration along the z axis in m/s²