Go - Piezo Speaker Bricklet

This is the description of the Go 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 Go API bindings is part of their general description. Additional documentation can be found on godoc.org.

Examples

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

Beep

Download (example_beep.go)

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
package main

import (
    "fmt"
    "github.com/Tinkerforge/go-api-bindings/ipconnection"
    "github.com/Tinkerforge/go-api-bindings/piezo_speaker_bricklet"
)

const ADDR string = "localhost:4223"
const UID string = "XYZ" // Change XYZ to the UID of your Piezo Speaker Bricklet.

func main() {
    ipcon := ipconnection.New()
    defer ipcon.Close()
    ps, _ := piezo_speaker_bricklet.New(UID, &ipcon) // Create device object.

    ipcon.Connect(ADDR) // Connect to brickd.
    defer ipcon.Disconnect()
    // Don't use device before ipcon is connected.

    // Make 2 second beep with a frequency of 1kHz
    ps.Beep(2000, 1000)

    fmt.Print("Press enter to exit.")
    fmt.Scanln()
}

Morse Code

Download (example_morse_code.go)

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
package main

import (
    "fmt"
    "github.com/Tinkerforge/go-api-bindings/ipconnection"
    "github.com/Tinkerforge/go-api-bindings/piezo_speaker_bricklet"
)

const ADDR string = "localhost:4223"
const UID string = "XYZ" // Change XYZ to the UID of your Piezo Speaker Bricklet.

func main() {
    ipcon := ipconnection.New()
    defer ipcon.Close()
    ps, _ := piezo_speaker_bricklet.New(UID, &ipcon) // Create device object.

    ipcon.Connect(ADDR) // Connect to brickd.
    defer ipcon.Disconnect()
    // Don't use device before ipcon is connected.

    // Morse SOS with a frequency of 2kHz
    ps.MorseCode("... --- ...", 2000)

    fmt.Print("Press enter to exit.")
    fmt.Scanln()
}

API

The Piezo Speaker Bricklet API is defined in the package github.com/Tinkerforge/go-api-bindings/piezo_speaker_bricklet

Nearly every function of the Go bindings can return an ipconnection.DeviceError, implementing the error interface. The error can have one of the following values:

  • ipconnection.DeviceErrorSuccess = 0
  • ipconnection.DeviceErrorInvalidParameter = 1
  • ipconnection.DeviceErrorFunctionNotSupported = 2
  • ipconnection.DeviceErrorUnknownError = 3

which correspond to the values returned from Bricks and Bricklets.

All functions listed below are thread-safe.

Basic Functions

func piezo_speaker_bricklet.New(uid string, ipcon *IPConnection) (device PiezoSpeakerBricklet, err error)
Parameters:
  • uid – Type: string
  • ipcon – Type: *IPConnection
Returns:
  • device – Type: PiezoSpeakerBricklet
  • err – Type: error

Creates a new PiezoSpeakerBricklet object with the unique device ID uid and adds it to the IPConnection ipcon:

device, err := piezo_speaker_bricklet.New("YOUR_DEVICE_UID", &ipcon)

This device object can be used after the IPConnection has been connected (see examples above).

func (*PiezoSpeakerBricklet) Beep(duration uint32, frequency uint16) (err error)
Parameters:
  • duration – Type: uint32, Unit: 1 ms, Range: [0 to 232 - 1] with constants
  • frequency – Type: uint16, Unit: 1 Hz, Range: [585 to 7100]
Returns:
  • err – Type: error

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 Calibrate()).

The following constants are available for this function:

For duration:

  • piezo_speaker_bricklet.BeepDurationOff = 0
  • piezo_speaker_bricklet.BeepDurationInfinite = 4294967295
func (*PiezoSpeakerBricklet) MorseCode(morse string, frequency uint16) (err error)
Parameters:
  • morse – Type: string, Length: up to 60
  • frequency – Type: uint16, Unit: 1 Hz, Range: [585 to 7100]
Returns:
  • err – Type: error

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

func (*PiezoSpeakerBricklet) Calibrate() (calibration bool, err error)
Returns:
  • calibration – Type: bool
  • err – Type: error

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.

func (*PiezoSpeakerBricklet) GetIdentity() (uid string, connectedUid string, position rune, hardwareVersion [3]uint8, firmwareVersion [3]uint8, deviceIdentifier uint16, err error)
Returns:
  • uid – Type: string, Length: up to 8
  • connectedUid – Type: string, Length: up to 8
  • position – Type: rune, Range: ['a' to 'h', 'i', 'z']
  • hardwareVersion – Type: [3]uint8
    • 0: major – Type: uint8, Range: [0 to 255]
    • 1: minor – Type: uint8, Range: [0 to 255]
    • 2: revision – Type: uint8, Range: [0 to 255]
  • firmwareVersion – Type: [3]uint8
    • 0: major – Type: uint8, Range: [0 to 255]
    • 1: minor – Type: uint8, Range: [0 to 255]
    • 2: revision – Type: uint8, Range: [0 to 255]
  • deviceIdentifier – Type: uint16, Range: [0 to 216 - 1]
  • err – Type: error

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. There is also a constant for the device identifier of this Bricklet.

Callbacks

Callbacks can be registered to receive time critical or recurring data from the device. The registration is done with the corresponding Register*Callback function, which returns a unique callback ID. This ID can be used to deregister the callback later with the corresponding Deregister*Callback function.

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.

func (*PiezoSpeakerBricklet) RegisterBeepFinishedCallback(func()) (registrationId uint64)
Returns:
  • registrationId – Type: uint64

This callback is triggered if a beep set by Beep() is finished

func (*PiezoSpeakerBricklet) RegisterMorseCodeFinishedCallback(func()) (registrationId uint64)
Returns:
  • registrationId – Type: uint64

This callback is triggered if the playback of the morse code set by MorseCode() is finished.

Virtual Functions

Virtual functions don't communicate with the device itself, but operate only on the API bindings device object. They can be called without the corresponding IP Connection object being connected.

func (*PiezoSpeakerBricklet) GetAPIVersion() (apiVersion [3]uint8, err error)
Returns:
  • apiVersion – Type: [3]uint8
    • 0: major – Type: uint8, Range: [0 to 255]
    • 1: minor – Type: uint8, Range: [0 to 255]
    • 2: revision – Type: uint8, Range: [0 to 255]
  • err – Type: error

Returns the version of the API definition implemented by this API bindings. This is neither the release version of this API bindings nor does it tell you anything about the represented Brick or Bricklet.

func (*PiezoSpeakerBricklet) GetResponseExpected(functionId uint8) (responseExpected bool, err error)
Parameters:
  • functionId – Type: uint8, Range: See constants
Returns:
  • responseExpected – Type: bool
  • err – Type: error

Returns the response expected flag for the function specified by the function ID parameter. It is true if the function is expected to send a response, false otherwise.

For getter functions this is enabled by default and cannot be disabled, because those functions will always send a response. For callback configuration functions it is enabled by default too, but can be disabled by SetResponseExpected(). For setter functions it is disabled by default and can be enabled.

Enabling the response expected flag for a setter function allows to detect timeouts and other error conditions calls of this setter as well. The device will then send a response for this purpose. If this flag is disabled for a setter function then no response is send and errors are silently ignored, because they cannot be detected.

The following constants are available for this function:

For functionId:

  • piezo_speaker_bricklet.FunctionBeep = 1
  • piezo_speaker_bricklet.FunctionMorseCode = 2
func (*PiezoSpeakerBricklet) SetResponseExpected(functionId uint8, responseExpected bool) (err error)
Parameters:
  • functionId – Type: uint8, Range: See constants
  • responseExpected – Type: bool
Returns:
  • err – Type: error

Changes the response expected flag of the function specified by the function ID parameter. This flag can only be changed for setter (default value: false) and callback configuration functions (default value: true). For getter functions it is always enabled.

Enabling the response expected flag for a setter function allows to detect timeouts and other error conditions calls of this setter as well. The device will then send a response for this purpose. If this flag is disabled for a setter function then no response is send and errors are silently ignored, because they cannot be detected.

The following constants are available for this function:

For functionId:

  • piezo_speaker_bricklet.FunctionBeep = 1
  • piezo_speaker_bricklet.FunctionMorseCode = 2
func (*PiezoSpeakerBricklet) SetResponseExpectedAll(responseExpected bool) (err error)
Parameters:
  • responseExpected – Type: bool
Returns:
  • err – Type: error

Changes the response expected flag for all setter and callback configuration functions of this device at once.

Constants

piezo_speaker_bricklet.DeviceIdentifier

This constant is used to identify a Piezo Speaker Bricklet.

The GetIdentity() function and the (*IPConnection) RegisterEnumerateCallback callback of the IPConnection have a deviceIdentifier parameter to specify the Brick's or Bricklet's type.

piezo_speaker_bricklet.DeviceDisplayName

This constant represents the human readable name of a Piezo Speaker Bricklet.