# Sensor

# Interface Declaration

{ "name": "system.sensor" }

# Import Module

import sensor from '@system.sensor' 
// or 
const sensor = require('@system.sensor')

# Interface Definition

# Methods

# sensor.subscribePressure(OBJECT)

Listens for pressure sensor data. If called multiple times, only the last call takes effect.

# Parameters:

Parameter	Type	Required	Description
callback	Function	Yes	Called back each time the positional information changes

# Callback Return Value:

Parameter	Type	Description
pressure	Number	Pressure, in hPa (hectopascals), floating-point number

# Example:

sensor.subscribePressure({
  callback: function(ret) {
    console.log(`handling callback, pressure = ${ret.pressure}`)
  }
})

# sensor.unsubscribePressure()

Cancels listening for pressure sensor data.

# Parameters:

None

# Example:

sensor.unsubscribePressure()

# sensor.subscribeAccelerometer(OBJECT)

Listens for accelerometer data.

# Parameters:

Parameter	Type	Required	Description
interval	String	No	Frequency at which the accelerometer data callback function is executed. Default is "normal".
callback	Function	Yes	Called back when gravity sensor data changes
fail	Function	No	Callback for subscription errors

# Valid Values for interval:

Value	Description
game	Suitable for game update callback frequency, approximately 20ms per call
ui	Suitable for UI update callback frequency, approximately 60ms per call
normal	Normal callback frequency, approximately 200ms per call

# Callback Return Value:

Parameter	Type	Description
x	Number	X-axis coordinate
y	Number	Y-axis coordinate
z	Number	Z-axis coordinate

# Example:

sensor.subscribeAccelerometer({
  callback: function(ret) {
    console.log(`handling callback, x = ${ret.x}, y = ${ret.y}, z = ${ret.z}`)
  },
  fail: function(msg, code) {
    console.log(`handling callback, fail:`, msg, code)
  }
})

# sensor.unsubscribeAccelerometer()

Cancels listening for accelerometer data.

# Parameters:

None

# Example:

sensor.unsubscribeAccelerometer()

# sensor.subscribeCompass(OBJECT)

Listens for compass data. If called multiple times, only the last call takes effect.

# Parameters:

Parameter	Type	Required	Description
callback	Function	Yes	Called back when compass data changes
fail	Function	No	Callback for subscription failure

# Callback Return Value:

Parameter	Type	Description
direction	Number	Angle between the device's y-axis and magnetic north. When facing north, the angle is 0; when facing south, it is π; when facing east, it is π/2; when facing west, it is -π/2
accuracy	Number	Accuracy, see compass accuracy description for details

# Error Codes Returned by fail:

Error Code	Description
1000	Current device does not support compass sensor

# Example:

sensor.subscribeCompass({
  callback: function (res) {
    console.log(`handling subscribeCompass callback, direction = ${res.direction}, accuracy = ${res.accuracy}`)
  },
  fail: function (data, code) {
    console.log(`handling subscribeCompass fail, code = ${code}`)
  }
})

# sensor.unsubscribeCompass()

Cancels listening for compass data.

# Parameters:

None

# Example:

sensor.unsubscribeCompass()

# Compass Accuracy Description:

Value	Description
3	High accuracy
2	Medium accuracy
1	Low accuracy
-1	Unreliable, sensor disconnected
0	Unreliable, reason unknown

# Support Details

Interface	Supported Device Products	Unsupported Device Products
subscribePressure	Xiaomi Watch S3, Xiaomi Band 9 Pro, Xiaomi Band 10, Xiaomi Watch S4	Xiaomi S1 Pro Sports Health Watch, Xiaomi Band 8 Pro, Xiaomi Band 9, Redmi Watch 4, Xiaomi Watch H1, REDMI Watch 5, REDMI Watch 6
unsubscribePressure	Xiaomi Watch S3, Xiaomi Band 9 Pro, Xiaomi Band 10, Xiaomi Watch S4	Xiaomi S1 Pro Sports Health Watch, Xiaomi Band 8 Pro, Xiaomi Band 9, Redmi Watch 4, Xiaomi Watch H1, REDMI Watch 5, REDMI Watch 6
subscribeAccelerometer	Xiaomi Band 9 / 9 Pro, Xiaomi Band 10	Xiaomi Watch S3, Xiaomi S1 Pro Sports Health Watch, Xiaomi Band 8 Pro, Redmi Watch 4, Xiaomi Watch H1, Xiaomi Watch S4, REDMI Watch 5, REDMI Watch 6
unsubscribeAccelerometer	Xiaomi Band 9 / 9 Pro, Xiaomi Band 10	Xiaomi Watch S3, Xiaomi S1 Pro Sports Health Watch, Xiaomi Band 8 Pro, Redmi Watch 4, Xiaomi Watch H1, Xiaomi Watch S4, REDMI Watch 5, REDMI Watch 6
subscribeCompass / unsubscribeCompass	Xiaomi Watch S4, REDMI Watch 5, REDMI Watch 6	Other Xiaomi band and watch devices

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