MQTT - Piezo Speaker Bricklet 2.0

This is the description of the MQTT API bindings for the Piezo Speaker Bricklet 2.0. General information and technical specifications for the Piezo Speaker 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).

Alarm

Download (example-alarm.txt)

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# Change XYZ to the UID of your Piezo Speaker Bricklet 2.0

setup:
    # 10 seconds of loud annoying fast alarm
    publish '{"start_frequency": 800, "end_frequency": 2000, "step_size": 10, "step_delay": 1, "volume": 10, "duration": 10000}' to tinkerforge/request/piezo_speaker_v2_bricklet/XYZ/set_alarm 

Beep

Download (example-beep.txt)

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# Change XYZ to the UID of your Piezo Speaker Bricklet 2.0

setup:
    # Make 2 second beep with a frequency of 1kHz
    publish '{"frequency": 1000, "volume": 0, "duration": 2000}' to tinkerforge/request/piezo_speaker_v2_bricklet/XYZ/set_beep 

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/piezo_speaker_v2_bricklet/<UID>/set_beep
Request payload:
 
  • frequency -- int
  • volume -- int
  • duration -- int (has symbols)

Beeps with the given frequency and volume for the duration in ms.

For example: If you set a duration of 1000, with a volume of 10 and a frequency value of 2000 the piezo buzzer will beep with maximum loudness for one second with a frequency of 2 kHz.

A duration of 0 stops the current beep if any is ongoing. A duration of 4294967295 results in an infinite beep.

The ranges are:

  • Frequency: 50Hz - 15000Hz
  • Volume: 0 - 10
  • Duration: 0ms - 4294967295ms

The following symbols are available for this function:

for duration:

  • "Off" = 0
  • "Infinite" = 4294967295
request/piezo_speaker_v2_bricklet/<UID>/get_beep
Response payload:
 
  • frequency -- int
  • volume -- int
  • duration -- int (has symbols)
  • duration_remaining -- int

Returns the last beep settings as set by request/piezo_speaker_v2_bricklet/<UID>/set_beep. If a beep is currently running it also returns the remaining duration of the beep in ms.

If the frequency or volume is updated during a beep (with request/piezo_speaker_v2_bricklet/<UID>/update_frequency or request/piezo_speaker_v2_bricklet/<UID>/update_volume) this function returns the updated value.

The following symbols are available for this function:

for duration:

  • "Off" = 0
  • "Infinite" = 4294967295
request/piezo_speaker_v2_bricklet/<UID>/set_alarm
Request payload:
 
  • start_frequency -- int
  • end_frequency -- int
  • step_size -- int
  • step_delay -- int
  • volume -- int
  • duration -- int (has symbols)

Creates an alarm (a tone that goes back and force between two specified frequencies).

The following parameters can be set:

  • Start Frequency: Start frequency of the alarm in Hz.
  • End Frequency: End frequency of the alarm in Hz.
  • Step Size: Size of one step of the sweep between the start/end frequencies in Hz.
  • Step Delay: Delay between two steps (duration of time that one tone is used in a sweep) in ms.
  • Duration: Duration of the alarm in ms.

A duration of 0 stops the current alarm if any is ongoing. A duration of 4294967295 results in an infinite alarm.

Below you can find two sets of example settings that you can try out. You can use these as a starting point to find an alarm signal that suits your application.

Example 1: 10 seconds of loud annoying fast alarm

  • Start Frequency = 800
  • End Frequency = 2000
  • Step Size = 10
  • Step Delay = 1
  • Volume = 10
  • Duration = 10000

Example 2: 10 seconds of soft siren sound with slow build-up

  • Start Frequency = 250
  • End Frequency = 750
  • Step Size = 1
  • Step Delay = 5
  • Volume = 0
  • Duration = 10000

The ranges are:

  • Start Frequency: 50Hz - 14999Hz (has to be smaller than end frequency)
  • End Frequency: 51Hz - 15000Hz (has to be bigger than start frequency)
  • Step Size: 1Hz - 65535Hz (has to be small enough to fit into the frequency range)
  • Step Delay: 1ms - 65535ms (has to be small enough to fit into the duration)
  • Volume: 0 - 10
  • Duration: 0ms - 4294967295ms

The following symbols are available for this function:

for duration:

  • "Off" = 0
  • "Infinite" = 4294967295
request/piezo_speaker_v2_bricklet/<UID>/get_alarm
Response payload:
 
  • start_frequency -- int
  • end_frequency -- int
  • step_size -- int
  • step_delay -- int
  • volume -- int
  • duration -- int (has symbols)
  • duration_remaining -- int
  • current_frequency -- int

Returns the last alarm settings as set by request/piezo_speaker_v2_bricklet/<UID>/set_alarm. If an alarm is currently running it also returns the remaining duration of the alarm in ms as well as the current frequency of the alarm in Hz.

If the volume is updated during a beep (with request/piezo_speaker_v2_bricklet/<UID>/update_volume) this function returns the updated value.

The following symbols are available for this function:

for duration:

  • "Off" = 0
  • "Infinite" = 4294967295
request/piezo_speaker_v2_bricklet/<UID>/update_volume
Request payload:
 
  • volume -- int

Updates the volume of an ongoing beep or alarm. The range of the volume is 0 to 10.

request/piezo_speaker_v2_bricklet/<UID>/update_frequency
Request payload:
 
  • frequency -- int

Updates the frequency of an ongoing beep. The range of the frequency is 50Hz to 15000Hz.

Advanced Functions

request/piezo_speaker_v2_bricklet/<UID>/get_spitfp_error_count
Response payload:
 
  • error_count_ack_checksum -- int
  • error_count_message_checksum -- int
  • error_count_frame -- int
  • error_count_overflow -- int

Returns the error count for the communication between Brick and Bricklet.

The errors are divided into

  • ACK checksum errors,
  • message checksum errors,
  • framing errors and
  • overflow errors.

The errors counts are for errors that occur on the Bricklet side. All Bricks have a similar function that returns the errors on the Brick side.

request/piezo_speaker_v2_bricklet/<UID>/set_bootloader_mode
Request payload:
 
  • mode -- int (has symbols)
Response payload:
 
  • status -- int (has symbols)

Sets the bootloader mode and returns the status after the requested mode change was instigated.

You can change from bootloader mode to firmware mode and vice versa. A change from bootloader mode to firmware mode will only take place if the entry function, device identifier and CRC are present and correct.

This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.

The following symbols are available for this function:

for mode:

  • "Bootloader" = 0
  • "Firmware" = 1
  • "BootloaderWaitForReboot" = 2
  • "FirmwareWaitForReboot" = 3
  • "FirmwareWaitForEraseAndReboot" = 4

for status:

  • "OK" = 0
  • "InvalidMode" = 1
  • "NoChange" = 2
  • "EntryFunctionNotPresent" = 3
  • "DeviceIdentifierIncorrect" = 4
  • "CRCMismatch" = 5
request/piezo_speaker_v2_bricklet/<UID>/get_bootloader_mode
Response payload:
 
  • mode -- int (has symbols)

Returns the current bootloader mode, see request/piezo_speaker_v2_bricklet/<UID>/set_bootloader_mode.

The following symbols are available for this function:

for mode:

  • "Bootloader" = 0
  • "Firmware" = 1
  • "BootloaderWaitForReboot" = 2
  • "FirmwareWaitForReboot" = 3
  • "FirmwareWaitForEraseAndReboot" = 4
request/piezo_speaker_v2_bricklet/<UID>/set_write_firmware_pointer
Request payload:
 
  • pointer -- int

Sets the firmware pointer for request/piezo_speaker_v2_bricklet/<UID>/write_firmware. The pointer has to be increased by chunks of size 64. The data is written to flash every 4 chunks (which equals to one page of size 256).

This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.

request/piezo_speaker_v2_bricklet/<UID>/write_firmware
Request payload:
 
  • data -- [int,... (x64)]
Response payload:
 
  • status -- int

Writes 64 Bytes of firmware at the position as written by request/piezo_speaker_v2_bricklet/<UID>/set_write_firmware_pointer before. The firmware is written to flash every 4 chunks.

You can only write firmware in bootloader mode.

This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.

request/piezo_speaker_v2_bricklet/<UID>/set_status_led_config
Request payload:
 
  • config -- int (has symbols)

Sets the status LED configuration. By default the LED shows communication traffic between Brick and Bricklet, it flickers once for every 10 received data packets.

You can also turn the LED permanently on/off or show a heartbeat.

If the Bricklet is in bootloader mode, the LED is will show heartbeat by default.

The following symbols are available for this function:

for config:

  • "Off" = 0
  • "On" = 1
  • "ShowHeartbeat" = 2
  • "ShowStatus" = 3
request/piezo_speaker_v2_bricklet/<UID>/get_status_led_config
Response payload:
 
  • config -- int (has symbols)

Returns the configuration as set by request/piezo_speaker_v2_bricklet/<UID>/set_status_led_config

The following symbols are available for this function:

for config:

  • "Off" = 0
  • "On" = 1
  • "ShowHeartbeat" = 2
  • "ShowStatus" = 3
request/piezo_speaker_v2_bricklet/<UID>/get_chip_temperature
Response payload:
 
  • temperature -- int

Returns the temperature in °C as measured inside the microcontroller. The value returned is not the ambient temperature!

The temperature is only proportional to the real temperature and it has bad accuracy. Practically it is only useful as an indicator for temperature changes.

request/piezo_speaker_v2_bricklet/<UID>/reset

Calling this function will reset the Bricklet. All configurations will be lost.

After a reset you have to create new device objects, calling functions on the existing ones will result in undefined behavior!

request/piezo_speaker_v2_bricklet/<UID>/write_uid
Request payload:
 
  • uid -- int

Writes a new UID into flash. If you want to set a new UID you have to decode the Base58 encoded UID string into an integer first.

We recommend that you use Brick Viewer to change the UID.

request/piezo_speaker_v2_bricklet/<UID>/read_uid
Response payload:
 
  • uid -- int

Returns the current UID as an integer. Encode as Base58 to get the usual string version.

request/piezo_speaker_v2_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 Piezo Speaker 2.0'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_speaker_v2_bricklet/<UID>/beep_finished
Request payload:
 
  • register -- bool

A callback can be registered for this event by publishing to the .../register/piezo_speaker_v2_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_v2_bricklet/<UID>/beep_finished[/<SUFFIX>] topic for each registered suffix.

This callback is triggered if a beep set by request/piezo_speaker_v2_bricklet/<UID>/set_beep is finished

register/piezo_speaker_v2_bricklet/<UID>/alarm_finished
Request payload:
 
  • register -- bool

A callback can be registered for this event by publishing to the .../register/piezo_speaker_v2_bricklet/<UID>/alarm_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_v2_bricklet/<UID>/alarm_finished[/<SUFFIX>] topic for each registered suffix.

This callback is triggered if a alarm set by request/piezo_speaker_v2_bricklet/<UID>/set_alarm is finished