MQTT - Piezo Speaker Bricklet¶

Beep¶

Download (example-beep.txt)

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# Change XYZ to the UID of your Piezo Speaker Bricklet

setup:
    # Make 2 second beep with a frequency of 1kHz
    publish '{"duration": 2000, "frequency": 1000}' to tinkerforge/request/piezo_speaker_bricklet/XYZ/beep

Morse Code¶

Download (example-morse-code.txt)

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# Change XYZ to the UID of your Piezo Speaker Bricklet

setup:
    # Morse SOS with a frequency of 2kHz
    publish '{"morse": "... --- ...", "frequency": 2000}' to tinkerforge/request/piezo_speaker_bricklet/XYZ/morse_code

Basic Functions¶

request/piezo_speaker_bricklet/<UID>/beep¶

Request:	duration – Type: int, Unit: 1 ms, Range: [0 to 232 - 1] with symbols frequency – Type: int, Unit: 1 Hz, Range: [585 to 7100]
Response:	no response

Beeps with the given frequency for the given duration.

Changed in version 2.0.2 (Plugin): A duration of 0 stops the current beep if any, the frequency parameter is ignored. A duration of 4294967295 results in an infinite beep.

The Piezo Speaker Bricklet can only approximate the frequency, it will play the best possible match by applying the calibration (see request/piezo_speaker_bricklet/<UID>/calibrate).

The following symbols are available for this function:

For duration:

• "off" = 0
• "infinite" = 4294967295

request/piezo_speaker_bricklet/<UID>/morse_code¶

Request:	morse – Type: string, Length: up to 60 frequency – Type: int, Unit: 1 Hz, Range: [585 to 7100]
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_speaker_bricklet/<UID>/calibrate¶

Request:	empty payload
Response:	calibration – Type: bool

The Piezo Speaker Bricklet can play 512 different tones. This function plays each tone and measures the exact frequency back. The result is a mapping between setting value and frequency. This mapping is stored in the EEPROM and loaded on startup.

The Bricklet should come calibrated, you only need to call this function (once) every time you reflash the Bricklet plugin.

Returns true after the calibration finishes.

request/piezo_speaker_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", "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). A Bricklet connected to an Isolator Bricklet is always at 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 Speaker'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.

register/piezo_speaker_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_speaker_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_speaker_bricklet/<UID>/beep_finished[/<SUFFIX>] topic for each registered suffix.

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

register/piezo_speaker_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_speaker_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_speaker_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_speaker_bricklet/<UID>/morse_code is finished.