MQTT - Piezo Buzzer Bricklet

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

Beep

Download (example-beep.txt)

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# Change XYZ to the UID of your Piezo Buzzer Bricklet

setup:
    # Make 2 second beep
    publish '{"duration": 2000}' to tinkerforge/request/piezo_buzzer_bricklet/XYZ/beep

Morse Code

Download (example-morse-code.txt)

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# Change XYZ to the UID of your Piezo Buzzer Bricklet

setup:
    # Morse SOS
    publish '{"morse": "... --- ..."}' to tinkerforge/request/piezo_buzzer_bricklet/XYZ/morse_code

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/piezo_buzzer_bricklet/<UID>/beep
Request:
  • duration – Type: int, Unit: 1 ms, Range: [0 to 232 - 1]
Response:
  • no response

Beeps for the given duration.

request/piezo_buzzer_bricklet/<UID>/morse_code
Request:
  • morse – Type: string, Length: up to 60
Response:
  • no response

Sets morse code that will be played by the piezo buzzer. The morse code is given as a string consisting of "." (dot), "-" (minus) and " " (space) for dits, dahs and pauses. Every other character is ignored.

For example: If you set the string "...---...", the piezo buzzer will beep nine times with the durations "short short short long long long short short short".

Advanced Functions

request/piezo_buzzer_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 Piezo Buzzer's name in a human readable form.

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/piezo_buzzer_bricklet/<UID>/beep_finished
Register Request:
  • register – Type: bool
Callback Response:
  • empty payload

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

This callback is triggered if a beep set by request/piezo_buzzer_bricklet/<UID>/beep is finished

register/piezo_buzzer_bricklet/<UID>/morse_code_finished
Register Request:
  • register – Type: bool
Callback Response:
  • empty payload

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

This callback is triggered if the playback of the morse code set by request/piezo_buzzer_bricklet/<UID>/morse_code is finished.