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Software / API Bindings / openHAB / API Reference and Examples / Bricklets / Sound Pressure Level Bricklet

openHAB - Sound Pressure Level Bricklet

Warning

The openHAB bindings are still in beta, but the development was stopped.

This is the description of the openHAB 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 openHAB API bindings is part of their general description.

Thing

UID:
  • tinkerforge:brickletsoundpressurelevel:[UID]
Required firmware version:
  • 2.0.0
Firmware update supported:
  • yes
Channels:
Actions:
Parameters:
  • FFT Size – Type: Choice, Default: 1024
  • 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.
  • Options: 128, 256, 512, 1024

  • Weighting – Type: Choice, Default: dB(A)
  • The Bricklet supports different weighting functions. 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.
  • Options: dB(A), dB(B), dB(C), dB(D), dB(Z), ITU-R 468

  • Status LED Configuration – Type: Choice, Default: Show Status
  • 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.
  • Options: Off, On, Show Heartbeat, Show Status

Channels

Sound Pressure

The measured Sound Pressure

Type:
  • Number:Dimensionless
UID:
  • tinkerforge:brickletsoundpressurelevel:[UID]:BrickletSoundPressureLevelDecibel
Read only:
  • Yes
Unit:
  • Decibel
Range:
  • 0 Decibel to 12 Decibel (Step 0.1 Decibel)
Parameters:
  • Update Interval – Type: integer, Default: 1000, Unit: ms, Min: 0, Max: 4294967295
  • Specifies the update interval in milliseconds. A value of 0 disables automatic updates.

Actions

Actions can be used in rules by creating an action object. All actions return a Map<String, Object>. Returned values can be accessed by name, sometimes the type deduction needs some hints, as shown below:

val actions = getActions("tinkerforge", "tinkerforge:brickletsoundpressurelevel:[UID]")
val hwVersion = actions.brickletSoundPressureLevelGetIdentity().get("hardwareVersion") as short[]
logInfo("Example", "Hardware version: " + hwVersion.get(0) + "." + hwVersion.get(1) + "." + hwVersion.get(2))

Basic Actions

brickletSoundPressureLevelGetDecibel()
Return Map:
  • decibel – Type: int, Unit: 1/10 dB, Range: [0 to 120]

Returns the measured sound pressure in decibels.

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 the thing configuration.

By default dB(A) will be used.

If you want to get the value periodically, it is recommended to use the Sound Pressure channel. You can set the channel configuration with the configuration of Sound Pressure.

brickletSoundPressureLevelGetSpectrum()
Return Map:
  • spectrum – Type: int[], Length: variable, Unit: ? dB, Range: [0 to 216 - 1]

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

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 the thing configuration 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.

brickletSoundPressureLevelGetConfiguration()
Return Map:
  • fftSize – Type: int, Range: See constants, Default: 3
  • weighting – Type: int, Range: See constants, Default: 0

Returns the configuration as set by the thing configuration.

The following constants are available for this function:

For fftSize:

  • val FFT_SIZE_128 = 0
  • val FFT_SIZE_256 = 1
  • val FFT_SIZE_512 = 2
  • val FFT_SIZE_1024 = 3

For weighting:

  • val WEIGHTING_A = 0
  • val WEIGHTING_B = 1
  • val WEIGHTING_C = 2
  • val WEIGHTING_D = 3
  • val WEIGHTING_Z = 4
  • val WEIGHTING_ITU_R_468 = 5

Advanced Actions

brickletSoundPressureLevelGetChipTemperature()
Return Map:
  • temperature – Type: int, Unit: 1 °C, Range: [-215 to 215 - 1]

Returns the temperature 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.

brickletSoundPressureLevelGetStatusLEDConfig()
Return Map:
  • config – Type: int, Range: See constants, Default: 3

Returns the configuration as set by the thing configuration

The following constants are available for this function:

For config:

  • val STATUS_LED_CONFIG_OFF = 0
  • val STATUS_LED_CONFIG_ON = 1
  • val STATUS_LED_CONFIG_SHOW_HEARTBEAT = 2
  • val STATUS_LED_CONFIG_SHOW_STATUS = 3
brickletSoundPressureLevelGetSPITFPErrorCount()
Return Map:
  • errorCountAckChecksum – Type: long, Range: [0 to 232 - 1]
  • errorCountMessageChecksum – Type: long, Range: [0 to 232 - 1]
  • errorCountFrame – Type: long, Range: [0 to 232 - 1]
  • errorCountOverflow – Type: long, Range: [0 to 232 - 1]

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.

brickletSoundPressureLevelReset()

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!

brickletSoundPressureLevelGetIdentity()
Return Map:
  • uid – Type: String, Length: up to 8
  • connectedUid – Type: String, Length: up to 8
  • position – Type: char, Range: ['a' to 'h', 'z']
  • hardwareVersion – Type: short[], Length: 3
    • 0: major – Type: short, Range: [0 to 255]
    • 1: minor – Type: short, Range: [0 to 255]
    • 2: revision – Type: short, Range: [0 to 255]
  • firmwareVersion – Type: short[], Length: 3
    • 0: major – Type: short, Range: [0 to 255]
    • 1: minor – Type: short, Range: [0 to 255]
    • 2: revision – Type: short, Range: [0 to 255]
  • deviceIdentifier – Type: int, Range: [0 to 216 - 1]

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. 

Internal Actions

brickletSoundPressureLevelReadUID()
Return Map:
  • uid – Type: long, Range: [0 to 232 - 1]

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