LabVIEW - Sound Pressure Level Bricklet

This is the description of the LabVIEW API bindings for the Sound Pressure Level Bricklet. General information and technical specifications for the Sound Pressure Level Bricklet are summarized in its hardware description.

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

API

Generally, every method of the LabVIEW bindings that outputs a value can report a Tinkerforge.TimeoutException. This error gets reported if the device did not respond. If a cable based connection is used, it is unlikely that this exception gets thrown (assuming nobody plugs the device out). However, if a wireless connection is used, timeouts will occur if the distance to the device gets too big.

The namespace for all Brick/Bricklet bindings and the IPConnection is Tinkerforge.*.

Basic Functions

BrickletSoundPressureLevel(uid, ipcon) → soundPressureLevel
Input:
  • uid -- String
  • ipcon -- .NET Refnum (IPConnection)
Output:
  • soundPressureLevel -- .NET Refnum (BrickletSoundPressureLevel)

Creates an object with the unique device ID uid. This object can then be used after the IP Connection is connected (see examples above).

BrickletSoundPressureLevel.GetDecibel() → decibel
Output:
  • decibel -- Int32

Returns the measured sound pressure in decibels. The values are given in dB/10 (tenths dB).

The Bricklet supports the weighting standards dB(A), dB(B), dB(C), dB(D), dB(Z) and ITU-R 468. You can configure the weighting with SetConfiguration().

By default dB(A) will be used.

If you want to get the value periodically, it is recommended to use the DecibelCallback callback. You can set the callback configuration with SetDecibelCallbackConfiguration().

BrickletSoundPressureLevel.GetSpectrum() → spectrum
Output:
  • spectrum -- Int32[]

Returns the frequency spectrum. The length of the spectrum is between 512 (FFT size 1024) and 64 (FFT size 128). See SetConfiguration().

Each array element is one bin of the FFT. The first bin is always the DC offset and the other bins have a size between 40Hz (FFT size 1024) and 320Hz (FFT size 128).

In sum the frequency of the spectrum always has a range from 0 to 20480Hz (the FFT is applied to samples with a frequency of 40960Hz).

The returned data is already equalized, which means that the microphone frequency response is compensated and the weighting function is applied (see SetConfiguration() for the available weighting standards). Use dB(Z) if you need the unaltered spectrum.

The values are not in dB form yet. If you want a proper dB scale of the spectrum you have to apply the formula f(x) = 20*log10(max(1, x/sqrt(2))) on each value.

BrickletSoundPressureLevel.SetConfiguration(fftSize, weighting)
Input:
  • fftSize -- Byte
  • weighting -- Byte

Sets the Sound Pressure Level Bricklet configuration.

With different FFT sizes the Bricklet has a different amount of samples per second and the size of the FFT bins changes. The higher the FFT size the more precise is the result of the dB(X) calculation.

Available FFT sizes are:

  • 1024: 512 bins, 10 samples per second, each bin has size 40Hz
  • 512: 256 bins, 20 samples per second, each bin has size 80Hz
  • 256: 128 bins, 40 samples per second, each bin has size 160Hz
  • 128: 64 bins, 80 samples per second, each bin has size 320Hz

The Bricklet supports different weighting functions. You can choose between dB(A), dB(B), dB(C), dB(D), dB(Z) and ITU-R 468.

dB(A/B/C/D) are the standard dB weighting curves. dB(A) is often used to measure volumes at concerts etc. dB(Z) has a flat response, no weighting is applied. ITU-R 468 is an ITU weighting standard mostly used in the UK and Europe.

The defaults are FFT size 1024 and weighting standard dB(A).

The following constants are available for this function:

  • BrickletSoundPressureLevel.FFT_SIZE_128 = 0
  • BrickletSoundPressureLevel.FFT_SIZE_256 = 1
  • BrickletSoundPressureLevel.FFT_SIZE_512 = 2
  • BrickletSoundPressureLevel.FFT_SIZE_1024 = 3
  • BrickletSoundPressureLevel.WEIGHTING_A = 0
  • BrickletSoundPressureLevel.WEIGHTING_B = 1
  • BrickletSoundPressureLevel.WEIGHTING_C = 2
  • BrickletSoundPressureLevel.WEIGHTING_D = 3
  • BrickletSoundPressureLevel.WEIGHTING_Z = 4
  • BrickletSoundPressureLevel.WEIGHTING_ITU_R_468 = 5
BrickletSoundPressureLevel.GetConfiguration() → fftSize, weighting
Output:
  • fftSize -- Byte
  • weighting -- Byte

Returns the configuration as set by SetConfiguration().

The following constants are available for this function:

  • BrickletSoundPressureLevel.FFT_SIZE_128 = 0
  • BrickletSoundPressureLevel.FFT_SIZE_256 = 1
  • BrickletSoundPressureLevel.FFT_SIZE_512 = 2
  • BrickletSoundPressureLevel.FFT_SIZE_1024 = 3
  • BrickletSoundPressureLevel.WEIGHTING_A = 0
  • BrickletSoundPressureLevel.WEIGHTING_B = 1
  • BrickletSoundPressureLevel.WEIGHTING_C = 2
  • BrickletSoundPressureLevel.WEIGHTING_D = 3
  • BrickletSoundPressureLevel.WEIGHTING_Z = 4
  • BrickletSoundPressureLevel.WEIGHTING_ITU_R_468 = 5

Advanced Functions

BrickletSoundPressureLevel.GetAPIVersion() → apiVersion
Output:
  • apiVersion -- Byte[3]

Returns the version of the API definition (major, minor, revision) 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.

BrickletSoundPressureLevel.GetResponseExpected(functionId) → responseExpected
Input:
  • functionId -- Byte
Output:
  • responseExpected -- Boolean

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.

See SetResponseExpected() for the list of function ID constants available for this function.

BrickletSoundPressureLevel.SetResponseExpected(functionId, responseExpected)
Input:
  • functionId -- Byte
  • responseExpected -- Boolean

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 function ID constants are available for this function:

  • BrickletSoundPressureLevel.FUNCTION_SET_DECIBEL_CALLBACK_CONFIGURATION = 2
  • BrickletSoundPressureLevel.FUNCTION_SET_SPECTRUM_CALLBACK_CONFIGURATION = 6
  • BrickletSoundPressureLevel.FUNCTION_SET_CONFIGURATION = 9
  • BrickletSoundPressureLevel.FUNCTION_SET_WRITE_FIRMWARE_POINTER = 237
  • BrickletSoundPressureLevel.FUNCTION_SET_STATUS_LED_CONFIG = 239
  • BrickletSoundPressureLevel.FUNCTION_RESET = 243
  • BrickletSoundPressureLevel.FUNCTION_WRITE_UID = 248
BrickletSoundPressureLevel.SetResponseExpectedAll(responseExpected)
Input:
  • responseExpected -- Boolean

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

BrickletSoundPressureLevel.GetSPITFPErrorCount() → errorCountAckChecksum, errorCountMessageChecksum, errorCountFrame, errorCountOverflow
Output:
  • errorCountAckChecksum -- Int64
  • errorCountMessageChecksum -- Int64
  • errorCountFrame -- Int64
  • errorCountOverflow -- Int64

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.

BrickletSoundPressureLevel.SetBootloaderMode(mode) → status
Input:
  • mode -- Byte
Output:
  • status -- Byte

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 constants are available for this function:

  • BrickletSoundPressureLevel.BOOTLOADER_MODE_BOOTLOADER = 0
  • BrickletSoundPressureLevel.BOOTLOADER_MODE_FIRMWARE = 1
  • BrickletSoundPressureLevel.BOOTLOADER_MODE_BOOTLOADER_WAIT_FOR_REBOOT = 2
  • BrickletSoundPressureLevel.BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_REBOOT = 3
  • BrickletSoundPressureLevel.BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_ERASE_AND_REBOOT = 4
  • BrickletSoundPressureLevel.BOOTLOADER_STATUS_OK = 0
  • BrickletSoundPressureLevel.BOOTLOADER_STATUS_INVALID_MODE = 1
  • BrickletSoundPressureLevel.BOOTLOADER_STATUS_NO_CHANGE = 2
  • BrickletSoundPressureLevel.BOOTLOADER_STATUS_ENTRY_FUNCTION_NOT_PRESENT = 3
  • BrickletSoundPressureLevel.BOOTLOADER_STATUS_DEVICE_IDENTIFIER_INCORRECT = 4
  • BrickletSoundPressureLevel.BOOTLOADER_STATUS_CRC_MISMATCH = 5
BrickletSoundPressureLevel.GetBootloaderMode() → mode
Output:
  • mode -- Byte

Returns the current bootloader mode, see SetBootloaderMode().

The following constants are available for this function:

  • BrickletSoundPressureLevel.BOOTLOADER_MODE_BOOTLOADER = 0
  • BrickletSoundPressureLevel.BOOTLOADER_MODE_FIRMWARE = 1
  • BrickletSoundPressureLevel.BOOTLOADER_MODE_BOOTLOADER_WAIT_FOR_REBOOT = 2
  • BrickletSoundPressureLevel.BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_REBOOT = 3
  • BrickletSoundPressureLevel.BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_ERASE_AND_REBOOT = 4
BrickletSoundPressureLevel.SetWriteFirmwarePointer(pointer)
Input:
  • pointer -- Int64

Sets the firmware pointer for WriteFirmware(). 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.

BrickletSoundPressureLevel.WriteFirmware(data) → status
Input:
  • data -- Byte[64]
Output:
  • status -- Byte

Writes 64 Bytes of firmware at the position as written by SetWriteFirmwarePointer() 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.

BrickletSoundPressureLevel.SetStatusLEDConfig(config)
Input:
  • config -- Byte

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 constants are available for this function:

  • BrickletSoundPressureLevel.STATUS_LED_CONFIG_OFF = 0
  • BrickletSoundPressureLevel.STATUS_LED_CONFIG_ON = 1
  • BrickletSoundPressureLevel.STATUS_LED_CONFIG_SHOW_HEARTBEAT = 2
  • BrickletSoundPressureLevel.STATUS_LED_CONFIG_SHOW_STATUS = 3
BrickletSoundPressureLevel.GetStatusLEDConfig() → config
Output:
  • config -- Byte

Returns the configuration as set by SetStatusLEDConfig()

The following constants are available for this function:

  • BrickletSoundPressureLevel.STATUS_LED_CONFIG_OFF = 0
  • BrickletSoundPressureLevel.STATUS_LED_CONFIG_ON = 1
  • BrickletSoundPressureLevel.STATUS_LED_CONFIG_SHOW_HEARTBEAT = 2
  • BrickletSoundPressureLevel.STATUS_LED_CONFIG_SHOW_STATUS = 3
BrickletSoundPressureLevel.GetChipTemperature() → temperature
Output:
  • temperature -- Int16

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.

BrickletSoundPressureLevel.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!

BrickletSoundPressureLevel.WriteUID(uid)
Input:
  • uid -- Int64

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.

BrickletSoundPressureLevel.ReadUID() → uid
Output:
  • uid -- Int64

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

BrickletSoundPressureLevel.GetIdentity() → uid, connectedUid, position, hardwareVersion, firmwareVersion, deviceIdentifier
Output:
  • uid -- String
  • connectedUid -- String
  • position -- Char
  • hardwareVersion -- Byte[3]
  • firmwareVersion -- Byte[3]
  • deviceIdentifier -- Int32

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

Callback Configuration Functions

BrickletSoundPressureLevel.SetDecibelCallbackConfiguration(period, valueHasToChange, option, min, max)
Input:
  • period -- Int64
  • valueHasToChange -- Boolean
  • option -- Char
  • min -- Int32
  • max -- Int32

The period in ms is the period with which the DecibelCallback callback is triggered periodically. A value of 0 turns the callback off.

If the value has to change-parameter is set to true, the callback is only triggered after the value has changed. If the value didn't change within the period, the callback is triggered immediately on change.

If it is set to false, the callback is continuously triggered with the period, independent of the value.

It is furthermore possible to constrain the callback with thresholds.

The option-parameter together with min/max sets a threshold for the DecibelCallback callback.

The following options are possible:

Option Description
'x' Threshold is turned off
'o' Threshold is triggered when the value is outside the min and max values
'i' Threshold is triggered when the value is inside or equal to the min and max values
'<' Threshold is triggered when the value is smaller than the min value (max is ignored)
'>' Threshold is triggered when the value is greater than the min value (max is ignored)

If the option is set to 'x' (threshold turned off) the callback is triggered with the fixed period.

The default value is (0, false, 'x', 0, 0).

The following constants are available for this function:

  • BrickletSoundPressureLevel.THRESHOLD_OPTION_OFF = 'x'
  • BrickletSoundPressureLevel.THRESHOLD_OPTION_OUTSIDE = 'o'
  • BrickletSoundPressureLevel.THRESHOLD_OPTION_INSIDE = 'i'
  • BrickletSoundPressureLevel.THRESHOLD_OPTION_SMALLER = '<'
  • BrickletSoundPressureLevel.THRESHOLD_OPTION_GREATER = '>'
BrickletSoundPressureLevel.GetDecibelCallbackConfiguration() → period, valueHasToChange, option, min, max
Output:
  • period -- Int64
  • valueHasToChange -- Boolean
  • option -- Char
  • min -- Int32
  • max -- Int32

Returns the callback configuration as set by SetDecibelCallbackConfiguration().

The following constants are available for this function:

  • BrickletSoundPressureLevel.THRESHOLD_OPTION_OFF = 'x'
  • BrickletSoundPressureLevel.THRESHOLD_OPTION_OUTSIDE = 'o'
  • BrickletSoundPressureLevel.THRESHOLD_OPTION_INSIDE = 'i'
  • BrickletSoundPressureLevel.THRESHOLD_OPTION_SMALLER = '<'
  • BrickletSoundPressureLevel.THRESHOLD_OPTION_GREATER = '>'
BrickletSoundPressureLevel.SetSpectrumCallbackConfiguration(period)
Input:
  • period -- Int64

The period in ms is the period with which the SpectrumCallback callback is triggered periodically. A value of 0 turns the callback off.

Every new measured spectrum will be send at most once. Set the period to 1 to make sure that you get every spectrum.

The default value is 0.

BrickletSoundPressureLevel.GetSpectrumCallbackConfiguration() → period
Output:
  • period -- Int64

Returns the callback configuration as set by GetSpectrumCallbackConfiguration().

Callbacks

Callbacks can be registered to receive time critical or recurring data from the device. The registration is done by assigning a function to a callback property of the device object. The available callback property and their type of parameters 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.

event BrickletSoundPressureLevel.DecibelCallback(sender, decibel)
Input:
  • sender -- .NET Refnum (BrickletSoundPressureLevel)
  • decibel -- Int32

This callback is triggered periodically according to the configuration set by SetDecibelCallbackConfiguration().

The parameter is the same as GetDecibel().

event BrickletSoundPressureLevel.SpectrumCallback(sender, spectrum)
Input:
  • sender -- .NET Refnum (BrickletSoundPressureLevel)
  • spectrum -- Int32[]

This callback is triggered periodically according to the configuration set by SetSpectrumCallbackConfiguration().

The parameter is the same as GetSpectrum().

Constants

BrickletSoundPressureLevel.DEVICE_IDENTIFIER

This constant is used to identify a Sound Pressure Level Bricklet.

The GetIdentity() function and the EnumerateCallback callback of the IP Connection have a deviceIdentifier parameter to specify the Brick's or Bricklet's type.

BrickletSoundPressureLevel.DEVICE_DISPLAY_NAME

This constant represents the human readable name of a Sound Pressure Level Bricklet.