MQTT - Ambient Light Bricklet 2.0

This is the description of the MQTT API bindings for the Ambient Light Bricklet 2.0. General information and technical specifications for the Ambient Light Bricklet 2.0 are summarized in its hardware description.

An installation guide for the MQTT API bindings is part of their general description.

Examples

The example code below is Public Domain (CC0 1.0).

Simple

Download (example-simple.txt)

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# Change XYZ to the UID of your Ambient Light Bricklet 2.0

setup:
    # Get current illuminance
    subscribe to tinkerforge/response/ambient_light_v2_bricklet/XYZ/get_illuminance
    publish '' to tinkerforge/request/ambient_light_v2_bricklet/XYZ/get_illuminance

Callback

Download (example-callback.txt)

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# Change XYZ to the UID of your Ambient Light Bricklet 2.0

setup:
    # Handle incoming illuminance callbacks
    subscribe to tinkerforge/callback/ambient_light_v2_bricklet/XYZ/illuminance
    publish '{"register": true}' to tinkerforge/register/ambient_light_v2_bricklet/XYZ/illuminance # Register illuminance callback

    # Set period for illuminance callback to 1s (1000ms)
    # Note: The illuminance callback is only called every second
    #       if the illuminance has changed since the last call!
    publish '{"period": 1000}' to tinkerforge/request/ambient_light_v2_bricklet/XYZ/set_illuminance_callback_period

Threshold

Download (example-threshold.txt)

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# Change XYZ to the UID of your Ambient Light Bricklet 2.0

setup:
    # Get threshold callbacks with a debounce time of 10 seconds (10000ms)
    publish '{"debounce": 10000}' to tinkerforge/request/ambient_light_v2_bricklet/XYZ/set_debounce_period

    # Handle incoming illuminance reached callbacks
    subscribe to tinkerforge/callback/ambient_light_v2_bricklet/XYZ/illuminance_reached
    publish '{"register": true}' to tinkerforge/register/ambient_light_v2_bricklet/XYZ/illuminance_reached # Register illuminance_reached callback

    # Configure threshold for illuminance "greater than 500 lx"
    publish '{"option": "greater", "min": 50000, "max": 0}' to tinkerforge/request/ambient_light_v2_bricklet/XYZ/set_illuminance_callback_threshold

API

All published payloads to and from the MQTT bindings are in JSON format.

If an error occures, the bindings publish a JSON object containing the error message as member _ERROR. It is published on the corresponding response topic: .../response/... for .../request/... and .../callback/... for .../register/....

Basic Functions

request/ambient_light_v2_bricklet/<UID>/get_illuminance
Request:
  • empty payload
Response:
  • illuminance – Type: int, Unit: 1/100 lx, Range: [0 to 232 - 1]

Returns the illuminance of the ambient light sensor. The measurement range goes up to about 100000lux, but above 64000lux the precision starts to drop.

Changed in version 2.0.2 (Plugin): An illuminance of 0lux indicates that the sensor is saturated and the configuration should be modified, see request/ambient_light_v2_bricklet/<UID>/set_configuration.

If you want to get the illuminance periodically, it is recommended to use the register/ambient_light_v2_bricklet/<UID>/illuminance callback and set the period with request/ambient_light_v2_bricklet/<UID>/set_illuminance_callback_period.

Advanced Functions

request/ambient_light_v2_bricklet/<UID>/set_configuration
Request:
  • illuminance_range – Type: int, Range: See symbols, Default: 3
  • integration_time – Type: int, Range: See symbols, Default: 3
Response:
  • no response

Sets the configuration. It is possible to configure an illuminance range between 0-600lux and 0-64000lux and an integration time between 50ms and 400ms.

New in version 2.0.2 (Plugin): The unlimited illuminance range allows to measure up to about 100000lux, but above 64000lux the precision starts to drop.

A smaller illuminance range increases the resolution of the data. A longer integration time will result in less noise on the data.

Changed in version 2.0.2 (Plugin): If the actual measure illuminance is out-of-range then the current illuminance range maximum +0.01lux is reported by request/ambient_light_v2_bricklet/<UID>/get_illuminance and the register/ambient_light_v2_bricklet/<UID>/illuminance callback. For example, 800001 for the 0-8000lux range.

Changed in version 2.0.2 (Plugin): With a long integration time the sensor might be saturated before the measured value reaches the maximum of the selected illuminance range. In this case 0lux is reported by request/ambient_light_v2_bricklet/<UID>/get_illuminance and the register/ambient_light_v2_bricklet/<UID>/illuminance callback.

If the measurement is out-of-range or the sensor is saturated then you should configure the next higher illuminance range. If the highest range is already in use, then start to reduce the integration time.

The following symbols are available for this function:

For illuminance_range:

  • "unlimited" = 6
  • "64000lux" = 0
  • "32000lux" = 1
  • "16000lux" = 2
  • "8000lux" = 3
  • "1300lux" = 4
  • "600lux" = 5

For integration_time:

  • "50ms" = 0
  • "100ms" = 1
  • "150ms" = 2
  • "200ms" = 3
  • "250ms" = 4
  • "300ms" = 5
  • "350ms" = 6
  • "400ms" = 7
request/ambient_light_v2_bricklet/<UID>/get_configuration
Request:
  • empty payload
Response:
  • illuminance_range – Type: int, Range: See symbols, Default: 3
  • integration_time – Type: int, Range: See symbols, Default: 3

Returns the configuration as set by request/ambient_light_v2_bricklet/<UID>/set_configuration.

The following symbols are available for this function:

For illuminance_range:

  • "unlimited" = 6
  • "64000lux" = 0
  • "32000lux" = 1
  • "16000lux" = 2
  • "8000lux" = 3
  • "1300lux" = 4
  • "600lux" = 5

For integration_time:

  • "50ms" = 0
  • "100ms" = 1
  • "150ms" = 2
  • "200ms" = 3
  • "250ms" = 4
  • "300ms" = 5
  • "350ms" = 6
  • "400ms" = 7
request/ambient_light_v2_bricklet/<UID>/get_identity
Request:
  • empty payload
Response:
  • uid – Type: string, Length: up to 8
  • connected_uid – Type: string, Length: up to 8
  • position – Type: char, Range: ["a" to "h", "i", "z"]
  • hardware_version – Type: [int, ...], Length: 3
    • 0: major – Type: int, Range: [0 to 255]
    • 1: minor – Type: int, Range: [0 to 255]
    • 2: revision – Type: int, Range: [0 to 255]
  • firmware_version – Type: [int, ...], Length: 3
    • 0: major – Type: int, Range: [0 to 255]
    • 1: minor – Type: int, Range: [0 to 255]
    • 2: revision – Type: int, Range: [0 to 255]
  • device_identifier – Type: int, Range: [0 to 216 - 1]
  • _display_name – Type: string

Returns the UID, the UID where the Bricklet is connected to, the position, the hardware and firmware version as well as the device identifier.

The position can be 'a', 'b', 'c', 'd', 'e', 'f', 'g' or 'h' (Bricklet Port). The Raspberry Pi HAT (Zero) Brick is always at position 'i' and the Bricklet connected to an Isolator Bricklet is always as position 'z'.

The device identifier numbers can be found here. If symbolic output is not disabled, the device identifier is mapped to the corresponding name in the format used in topics.

The display name contains the Ambient Light 2.0's name in a human readable form.

Callback Configuration Functions

request/ambient_light_v2_bricklet/<UID>/set_illuminance_callback_period
Request:
  • period – Type: int, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0
Response:
  • no response

Sets the period with which the register/ambient_light_v2_bricklet/<UID>/illuminance callback is triggered periodically. A value of 0 turns the callback off.

The register/ambient_light_v2_bricklet/<UID>/illuminance callback is only triggered if the illuminance has changed since the last triggering.

request/ambient_light_v2_bricklet/<UID>/get_illuminance_callback_period
Request:
  • empty payload
Response:
  • period – Type: int, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0

Returns the period as set by request/ambient_light_v2_bricklet/<UID>/set_illuminance_callback_period.

request/ambient_light_v2_bricklet/<UID>/set_illuminance_callback_threshold
Request:
  • option – Type: char, Range: See symbols, Default: "x"
  • min – Type: int, Unit: 1/100 lx, Range: [0 to 232 - 1], Default: 0
  • max – Type: int, Unit: 1/100 lx, Range: [0 to 232 - 1], Default: 0
Response:
  • no response

Sets the thresholds for the register/ambient_light_v2_bricklet/<UID>/illuminance_reached callback.

The following options are possible:

Option Description
'x' Callback is turned off
'o' Callback is triggered when the illuminance is outside the min and max values
'i' Callback is triggered when the illuminance is inside the min and max values
'<' Callback is triggered when the illuminance is smaller than the min value (max is ignored)
'>' Callback is triggered when the illuminance is greater than the min value (max is ignored)

The following symbols are available for this function:

For option:

  • "off" = "x"
  • "outside" = "o"
  • "inside" = "i"
  • "smaller" = "<"
  • "greater" = ">"
request/ambient_light_v2_bricklet/<UID>/get_illuminance_callback_threshold
Request:
  • empty payload
Response:
  • option – Type: char, Range: See symbols, Default: "x"
  • min – Type: int, Unit: 1/100 lx, Range: [0 to 232 - 1], Default: 0
  • max – Type: int, Unit: 1/100 lx, Range: [0 to 232 - 1], Default: 0

Returns the threshold as set by request/ambient_light_v2_bricklet/<UID>/set_illuminance_callback_threshold.

The following symbols are available for this function:

For option:

  • "off" = "x"
  • "outside" = "o"
  • "inside" = "i"
  • "smaller" = "<"
  • "greater" = ">"
request/ambient_light_v2_bricklet/<UID>/set_debounce_period
Request:
  • debounce – Type: int, Unit: 1 ms, Range: [0 to 232 - 1], Default: 100
Response:
  • no response

Sets the period with which the threshold callbacks

are triggered, if the thresholds

keep being reached.

request/ambient_light_v2_bricklet/<UID>/get_debounce_period
Request:
  • empty payload
Response:
  • debounce – Type: int, Unit: 1 ms, Range: [0 to 232 - 1], Default: 100

Returns the debounce period as set by request/ambient_light_v2_bricklet/<UID>/set_debounce_period.

Callbacks

Callbacks can be registered to receive time critical or recurring data from the device. The registration is done with the corresponding .../register/... topic and an optional suffix. This suffix can be used to deregister the callback later.

Note

Using callbacks for recurring events is always preferred compared to using getters. It will use less USB bandwidth and the latency will be a lot better, since there is no round trip time.

register/ambient_light_v2_bricklet/<UID>/illuminance
Register Request:
  • register – Type: bool
Callback Response:
  • illuminance – Type: int, Unit: 1/100 lx, Range: [0 to 232 - 1]

A callback can be registered for this event by publishing to the .../register/ambient_light_v2_bricklet/<UID>/illuminance[/<SUFFIX>] topic with the payload "true". An added callback can be removed by publishing to the same topic with the payload "false". To support multiple (de)registrations, e.g. for message filtering, an optional suffix can be used.

If the callback is triggered, a message with it's payload is published under the corresponding .../callback/ambient_light_v2_bricklet/<UID>/illuminance[/<SUFFIX>] topic for each registered suffix.

This callback is triggered periodically with the period that is set by request/ambient_light_v2_bricklet/<UID>/set_illuminance_callback_period. The callback payload is the illuminance of the ambient light sensor.

The register/ambient_light_v2_bricklet/<UID>/illuminance callback is only triggered if the illuminance has changed since the last triggering.

register/ambient_light_v2_bricklet/<UID>/illuminance_reached
Register Request:
  • register – Type: bool
Callback Response:
  • illuminance – Type: int, Unit: 1/100 lx, Range: [0 to 232 - 1]

A callback can be registered for this event by publishing to the .../register/ambient_light_v2_bricklet/<UID>/illuminance_reached[/<SUFFIX>] topic with the payload "true". An added callback can be removed by publishing to the same topic with the payload "false". To support multiple (de)registrations, e.g. for message filtering, an optional suffix can be used.

If the callback is triggered, a message with it's payload is published under the corresponding .../callback/ambient_light_v2_bricklet/<UID>/illuminance_reached[/<SUFFIX>] topic for each registered suffix.

This callback is triggered when the threshold as set by request/ambient_light_v2_bricklet/<UID>/set_illuminance_callback_threshold is reached. The callback payload is the illuminance of the ambient light sensor.

If the threshold keeps being reached, the callback is triggered periodically with the period as set by request/ambient_light_v2_bricklet/<UID>/set_debounce_period.