MQTT - Temperature Bricklet

This is the description of the MQTT API bindings for the Temperature Bricklet. General information and technical specifications for the Temperature Bricklet 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 Temperature Bricklet

setup:
    # Get current temperature
    subscribe to tinkerforge/response/temperature_bricklet/XYZ/get_temperature
    publish '' to tinkerforge/request/temperature_bricklet/XYZ/get_temperature

Callback

Download (example-callback.txt)

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# Change XYZ to the UID of your Temperature Bricklet

setup:
    # Handle incoming temperature callbacks
    subscribe to tinkerforge/callback/temperature_bricklet/XYZ/temperature
    publish '{"register": true}' to tinkerforge/register/temperature_bricklet/XYZ/temperature # Register temperature callback
    
    # Set period for temperature callback to 1s (1000ms)
    # Note: The temperature callback is only called every second
    #       if the temperature has changed since the last call!
    publish '{"period": 1000}' to tinkerforge/request/temperature_bricklet/XYZ/set_temperature_callback_period

Threshold

Download (example-threshold.txt)

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# Change XYZ to the UID of your Temperature Bricklet

setup:
    # Get threshold callbacks with a debounce time of 10 seconds (10000ms)
    publish '{"debounce": 10000}' to tinkerforge/request/temperature_bricklet/XYZ/set_debounce_period
    
    # Handle incoming temperature reached callbacks
    subscribe to tinkerforge/callback/temperature_bricklet/XYZ/temperature_reached
    publish '{"register": true}' to tinkerforge/register/temperature_bricklet/XYZ/temperature_reached # Register temperature_reached callback
    
    # Configure threshold for temperature "greater than 30 °C"
    publish '{"option": "greater", "min": 3000, "max": 0}' to tinkerforge/request/temperature_bricklet/XYZ/set_temperature_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 attribute "_ERROR". It is published on the corresponding response topic: .../response/... for .../request/... and .../callback/... for .../register/....

Basic Functions

request/temperature_bricklet/<UID>/get_temperature
Response payload:
 
  • temperature -- int

Returns the temperature of the sensor. The value has a range of -2500 to 8500 and is given in °C/100, e.g. a value of 4223 means that a temperature of 42.23 °C is measured.

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

Advanced Functions

request/temperature_bricklet/<UID>/set_i2c_mode
Request payload:
 
  • mode -- int (has symbols)

Sets the I2C mode. Possible modes are:

  • 0: Fast (400kHz, default)
  • 1: Slow (100kHz)

If you have problems with obvious outliers in the Temperature Bricklet measurements, they may be caused by EMI issues. In this case it may be helpful to lower the I2C speed.

It is however not recommended to lower the I2C speed in applications where a high throughput needs to be achieved.

The following symbols are available for this function:

for mode:

  • "Fast" = 0
  • "Slow" = 1

New in version 2.0.1 (Plugin).

request/temperature_bricklet/<UID>/get_i2c_mode
Response payload:
 
  • mode -- int (has symbols)

Returns the I2C mode as set by request/temperature_bricklet/<UID>/set_i2c_mode.

The following symbols are available for this function:

for mode:

  • "Fast" = 0
  • "Slow" = 1

New in version 2.0.1 (Plugin).

request/temperature_bricklet/<UID>/get_identity
Response payload:
 
  • uid -- string
  • connected_uid -- string
  • position -- string
  • hardware_version -- [int,int,int]
  • firmware_version -- [int,int,int]
  • device_identifier -- int (has symbols)
  • _display_name -- 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' or 'd'.

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 Temperature's name in a human readable form.

Callback Configuration Functions

request/temperature_bricklet/<UID>/set_temperature_callback_period
Request payload:
 
  • period -- int

Sets the period in ms with which the register/temperature_bricklet/<UID>/temperature callback is triggered periodically. A value of 0 turns the callback off.

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

The default value is 0.

request/temperature_bricklet/<UID>/get_temperature_callback_period
Response payload:
 
  • period -- int

Returns the period as set by request/temperature_bricklet/<UID>/set_temperature_callback_period.

request/temperature_bricklet/<UID>/set_temperature_callback_threshold
Request payload:
 
  • option -- string (has symbols)
  • min -- int
  • max -- int

Sets the thresholds for the register/temperature_bricklet/<UID>/temperature_reached callback.

The following options are possible:

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

The default value is ('x', 0, 0).

The following symbols are available for this function:

for option:

  • "Off" = 'x'
  • "Outside" = 'o'
  • "Inside" = 'i'
  • "Smaller" = '<'
  • "Greater" = '>'
request/temperature_bricklet/<UID>/get_temperature_callback_threshold
Response payload:
 
  • option -- string (has symbols)
  • min -- int
  • max -- int

Returns the threshold as set by request/temperature_bricklet/<UID>/set_temperature_callback_threshold.

The following symbols are available for this function:

for option:

  • "Off" = 'x'
  • "Outside" = 'o'
  • "Inside" = 'i'
  • "Smaller" = '<'
  • "Greater" = '>'
request/temperature_bricklet/<UID>/set_debounce_period
Request payload:
 
  • debounce -- int

Sets the period in ms with which the threshold callback

is triggered, if the threshold

keeps being reached.

The default value is 100.

request/temperature_bricklet/<UID>/get_debounce_period
Response payload:
 
  • debounce -- int

Returns the debounce period as set by request/temperature_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/temperature_bricklet/<UID>/temperature
Request payload:
 
  • register -- bool
Response payload:
 
  • temperature -- int

A callback can be registered for this event by publishing to the .../register/temperature_bricklet/<UID>/temperature[/<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/temperature_bricklet/<UID>/temperature[/<SUFFIX>] topic for each registered suffix.

This callback is triggered periodically with the period that is set by request/temperature_bricklet/<UID>/set_temperature_callback_period. The callback payload is the temperature of the sensor.

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

register/temperature_bricklet/<UID>/temperature_reached
Request payload:
 
  • register -- bool
Response payload:
 
  • temperature -- int

A callback can be registered for this event by publishing to the .../register/temperature_bricklet/<UID>/temperature_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/temperature_bricklet/<UID>/temperature_reached[/<SUFFIX>] topic for each registered suffix.

This callback is triggered when the threshold as set by request/temperature_bricklet/<UID>/set_temperature_callback_threshold is reached. The callback payload is the temperature of the sensor.

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