Shell - Piezo Speaker Bricklet

This is the description of the Shell API bindings for the Piezo Speaker Bricklet. General information and technical specifications for the Piezo Speaker Bricklet are summarized in its hardware description.

An installation guide for the Shell API bindings is part of their general description.

Examples

The example code below is Public Domain (CC0 1.0).

Beep

Download (example-beep.sh)

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#!/bin/sh
# Connects to localhost:4223 by default, use --host and --port to change this

uid=XYZ # Change XYZ to the UID of your Piezo Speaker Bricklet

# Make 2 second beep with a frequency of 1kHz
tinkerforge call piezo-speaker-bricklet $uid beep 2000 1000

Morse Code

Download (example-morse-code.sh)

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#!/bin/sh
# Connects to localhost:4223 by default, use --host and --port to change this

uid=XYZ # Change XYZ to the UID of your Piezo Speaker Bricklet

# Morse SOS with a frequency of 2kHz
tinkerforge call piezo-speaker-bricklet $uid morse-code "... --- ..." 2000

API

Possible exit codes for all tinkerforge commands are:

  • 1: interrupted (ctrl+c)
  • 2: syntax error
  • 21: Python 2.5 or newer is required
  • 22: Python argparse module is missing
  • 23: socket error
  • 24: other exception
  • 25: invalid placeholder in format string
  • 26: authentication error
  • 201: timeout occurred
  • 209: invalid argument value
  • 210: function is not supported
  • 211: unknown error

Command Structure

The common options of the call and dispatch commands are documented here. The specific command structure is shown below.

tinkerforge call piezo-speaker-bricklet [<option>..] <uid> <function> [<argument>..]
Parameters:
  • <uid> -- string
  • <function> -- string

The call command is used to call a function of the Piezo Speaker Bricklet. It can take several options:

  • --help shows help for the specific call command and exits
  • --list-functions shows a list of known functions of the Piezo Speaker Bricklet and exits
tinkerforge dispatch piezo-speaker-bricklet [<option>..] <uid> <callback>
Parameters:
  • <uid> -- string
  • <callback> -- string

The dispatch command is used to dispatch a callback of the Piezo Speaker Bricklet. It can take several options:

  • --help shows help for the specific dispatch command and exits
  • --list-callbacks shows a list of known callbacks of the Piezo Speaker Bricklet and exits
tinkerforge call piezo-speaker-bricklet <uid> <function> [<option>..] [<argument>..]
Parameters:
  • <uid> -- string
  • <function> -- string

The <function> to be called can take different options depending of its kind. All functions can take the following options:

  • --help shows help for the specific function and exits

Getter functions can take the following options:

  • --execute <command> shell command line to execute for each incoming response (see section about output formatting for details)

Setter functions can take the following options:

  • --expect-response requests response and waits for it

The --expect-response option for setter functions allows to detect timeouts and other error conditions calls of setters as well. The device will then send a response for this purpose. If this option is not given for a setter function then no response is send and errors are silently ignored, because they cannot be detected.

tinkerforge dispatch piezo-speaker-bricklet <uid> <callback> [<option>..]
Parameters:
  • <uid> -- string
  • <callback> -- string

The <callback> to be dispatched can take several options:

  • --help shows help for the specific callback and exits
  • --execute <command> shell command line to execute for each incoming response (see section about output formatting for details)

Basic Functions

tinkerforge call piezo-speaker-bricklet <uid> beep <duration> <frequency>
Parameters:
  • <duration> -- int (has symbols)
  • <frequency> -- int
Output:

no output

Beeps with the given frequency for the duration in ms. For example: If you set a duration of 1000, with a frequency value of 2000 the piezo buzzer will beep for one second with a frequency of approximately 2 kHz.

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 frequency parameter can be set between 585 and 7100.

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

The following symbols are available for this function:

  • beep-duration-off = 0, for <duration>
  • beep-duration-infinite = 4294967295, for <duration>
tinkerforge call piezo-speaker-bricklet <uid> morse-code <morse> <frequency>
Parameters:
  • <morse> -- string
  • <frequency> -- int
Output:

no output

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. The second parameter is the frequency (see beep).

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".

The maximum string size is 60.

Advanced Functions

tinkerforge call piezo-speaker-bricklet <uid> calibrate
Output:
  • calibration -- 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.

tinkerforge call piezo-speaker-bricklet <uid> get-identity
Output:
  • uid -- string
  • connected-uid -- string
  • position -- char
  • hardware-version -- int,int,int
  • firmware-version -- int,int,int
  • device-identifier -- int (has symbols)

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

Callbacks

Callbacks can be used to receive time critical or recurring data from the device:

tinkerforge dispatch piezo-speaker-bricklet <uid> example

The available callbacks are described below.

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.

tinkerforge dispatch piezo-speaker-bricklet <uid> beep-finished
Output:no output

This callback is triggered if a beep set by beep is finished

tinkerforge dispatch piezo-speaker-bricklet <uid> morse-code-finished
Output:no output

This callback is triggered if the playback of the morse code set by morse-code is finished.