MQTT - Tilt Bricklet

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

setup:
    # Get current tilt state
    subscribe to tinkerforge/response/tilt_bricklet/XYZ/get_tilt_state
    publish '' to tinkerforge/request/tilt_bricklet/XYZ/get_tilt_state

Callback

Download (example-callback.txt)

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# Change XYZ to the UID of your Tilt Bricklet

setup:
    # Enable tilt state callback
    publish '' to tinkerforge/request/tilt_bricklet/XYZ/enable_tilt_state_callback 
    
    # Handle incoming tilt state callbacks
    subscribe to tinkerforge/callback/tilt_bricklet/XYZ/tilt_state
    publish '{"register": true}' to tinkerforge/register/tilt_bricklet/XYZ/tilt_state # Register tilt_state callback

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/tilt_bricklet/<UID>/get_tilt_state
Response payload:
  • state -- int (has symbols)

Returns the current tilt state. The state can either be

  • 0 = Closed: The ball in the tilt switch closes the circuit.
  • 1 = Open: The ball in the tilt switch does not close the circuit.
  • 2 = Closed Vibrating: The tilt switch is in motion (rapid change between open and close).
Tilt states

The following symbols are available for this function:

for state:

  • "Closed" = 0
  • "Open" = 1
  • "ClosedVibrating" = 2

Advanced Functions

request/tilt_bricklet/<UID>/get_identity
Response payload:
  • uid -- string
  • connected_uid -- string
  • position -- char
  • 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 Tilt's name in a human readable form.

Callback Configuration Functions

request/tilt_bricklet/<UID>/enable_tilt_state_callback

Enables the register/tilt_bricklet/<UID>/tilt_state callback.

request/tilt_bricklet/<UID>/disable_tilt_state_callback

Disables the register/tilt_bricklet/<UID>/tilt_state callback.

request/tilt_bricklet/<UID>/is_tilt_state_callback_enabled
Response payload:
  • enabled -- bool

Returns true if the register/tilt_bricklet/<UID>/tilt_state callback is enabled.

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/tilt_bricklet/<UID>/tilt_state
Request payload:
  • register -- bool
Response payload:
  • state -- int (has symbols)

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

This callback provides the current tilt state. It is called every time the state changes.

See request/tilt_bricklet/<UID>/get_tilt_state for a description of the states.

The following symbols are available for this function:

for state:

  • "Closed" = 0
  • "Open" = 1
  • "ClosedVibrating" = 2