Ambient Temperature (Thermometer) Sensor

Status of this document

This is a public copy of the editors’ draft. It is provided for discussion only and may change at any moment. Its publication here does not imply endorsement of its contents by W3C. Don’t cite this document other than as work in progress.

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This document was produced by the Device and Sensors Working Group.

This document was produced by a group operating under the 5 February 2004 W3C Patent Policy. W3C maintains a public list of any patent disclosures made in connection with the deliverables of the group; that page also includes instructions for disclosing a patent. An individual who has actual knowledge of a patent which the individual believes contains Essential Claim(s) must disclose the information in accordance with section 6 of the W3C Patent Policy.

This document is governed by the 1 September 2015 W3C Process Document.

1. Introduction

The Temperature Sensor extends the Generic Sensor API [GENERIC-SENSOR] to provide information about the ambient temperature, as detected by the device’s primary temperature sensor.

The temperature level is reported in either celsius, fahrenheit or kelvin and represents the local temperature level. Some devices, such as phones, might report inflated values due to the proximity of battery.

2. Examples

let sensor = new TemperatureSensor();
sensor.start();

sensor.onchange = event => console.log(event.reading.celsius);

sensor.onerror = function(event) {
    console.log(event.error.name, event.error.message);
};

3. Security and Privacy Considerations

There are no specific security and privacy considerations beyond those described in the Generic Sensor API [GENERIC-SENSOR].

4. Model

The Temperature Sensor’s associated Sensor subclass is the TemperatureSensor class.

The Temperature Sensor’s associated SensorReading subclass is the TemperatureSensorReading class.

The Temperature Sensor has a default sensor, which is the device’s main temperature detector.

The Temperature Sensor has a single supported reporting mode which is "auto".

The Temperature Sensor’s permission name is "temperature". It has no associated PermissionDescriptor.

The Temperature Sensor has an associated abstract operation to retrieve the sensor permission which must simply return a permission whose name is "temperature".

The Temperature Sensor has an associated abstract operation to construct a SensorReading object which creates a new TemperatureSensorReading object and sets each of its celsius, fahrenheit and kelvin attributes to positive infinity.

celsius is a value that represents the the local ambient temperature. Its unit is degrees Celsius, also known as centigrade.

fahrenheit is a value that represents the the local ambient temperature. Its unit is degrees Fahrenheit.

kelvin is a value that represents the the local ambient temperature. Its unit is degrees Kelvin.

5. API

5.1. The TemperatureSensor Interface

[Constructor(optional SensorOptions sensorOptions)]
interface TemperatureSensor : Sensor {
  readonly attribute TemperatureSensorReading? reading;
};

To Construct an TemperatureSensor Object the user agent must invoke the construct a Sensor object abstract operation.

5.2. The TemperatureSensorReading Interface

[Constructor(TemperatureSensorReadingInit temperatureSensorReadingInit)]
interface TemperatureSensorReading : SensorReading {
    readonly attribute unrestricted double? celsius;
    readonly attribute unrestricted double? fahrenheit;
    readonly attribute unrestricted double? kelvin;
};

dictionary TemperatureSensorReadingInit {
  unrestricted double? celsius;
  unrestricted double? fahrenheit;
  unrestricted double? kelvin;
};

5.2.1. The TemperatureSensorReading constructor

5.2.2. The celsius attribute

The celsius attribute of the TemperatureSensorReading interface represents the local ambient temperature level in degree Celsius, also known as centigrade.

5.2.3. The fahrenheit attribute

The fahrenheit attribute of the TemperatureSensorReading interface represents the local ambient temperature level in degree Fahrenheit.

5.2.4. The kelvin attribute

The kelvin attribute of the TemperatureSensorReading interface represents the local ambient temperature level in degree Kelvin.

6. Acknowledgements

Tobie Langel for the work on Generic Sensor API.

Conformance

Document conventions

Conformance requirements are expressed with a combination of descriptive assertions and RFC 2119 terminology. The key words “MUST”, “MUST NOT”, “REQUIRED”, “SHALL”, “SHALL NOT”, “SHOULD”, “SHOULD NOT”, “RECOMMENDED”, “MAY”, and “OPTIONAL” in the normative parts of this document are to be interpreted as described in RFC 2119. However, for readability, these words do not appear in all uppercase letters in this specification.

All of the text of this specification is normative except sections explicitly marked as non-normative, examples, and notes. [RFC2119]

Examples in this specification are introduced with the words “for example” or are set apart from the normative text with class="example", like this:

This is an example of an informative example.

Informative notes begin with the word “Note” and are set apart from the normative text with class="note", like this:

Note, this is an informative note.

Conformant Algorithms

Requirements phrased in the imperative as part of algorithms (such as "strip any leading space characters" or "return false and abort these steps") are to be interpreted with the meaning of the key word ("must", "should", "may", etc) used in introducing the algorithm.

Conformance requirements phrased as algorithms or specific steps can be implemented in any manner, so long as the end result is equivalent. In particular, the algorithms defined in this specification are intended to be easy to understand and are not intended to be performant. Implementers are encouraged to optimize.

Conformance Classes

A conformant user agent must implement all the requirements listed in this specification that are applicable to user agents.

A conformant server must implement all the requirements listed in this specification that are applicable to servers.

[Constructor(optional SensorOptions sensorOptions)] interface TemperatureSensor : Sensor { readonly attribute TemperatureSensorReading? reading; }; [Constructor(TemperatureSensorReadingInit temperatureSensorReadingInit)] interface TemperatureSensorReading : SensorReading { readonly attribute unrestricted double? celsius; readonly attribute unrestricted double? fahrenheit; readonly attribute unrestricted double? kelvin; }; dictionary TemperatureSensorReadingInit { unrestricted double? celsius; unrestricted double? fahrenheit; unrestricted double? kelvin; };