class Tinkerforge::BrickletSoundPressureLevel

Measures Sound Pressure Level in dB(A/B/C/D/Z)

Constants

CALLBACK_DECIBEL

This callback is triggered periodically according to the configuration set by BrickletSoundPressureLevel#set_decibel_callback_configuration.

The parameter is the same as BrickletSoundPressureLevel#get_decibel.

CALLBACK_SPECTRUM

This callback is triggered periodically according to the configuration set by BrickletSoundPressureLevel#set_spectrum_callback_configuration.

The parameter is the same as BrickletSoundPressureLevel#get_spectrum.

.. note

If reconstructing the value fails, the callback is triggered with nil for spectrum.

CALLBACK_SPECTRUM_LOW_LEVEL

See CALLBACK_SPECTRUM

Public Class Methods

new(uid, ipcon) click to toggle source

Creates an object with the unique device ID uid and adds it to the IP Connection ipcon.

Calls superclass method
# File lib/tinkerforge/bricklet_sound_pressure_level.rb, line 91
def initialize(uid, ipcon)
  super uid, ipcon, DEVICE_IDENTIFIER, DEVICE_DISPLAY_NAME

  @api_version = [2, 0, 0]

  @response_expected[FUNCTION_GET_DECIBEL] = RESPONSE_EXPECTED_ALWAYS_TRUE
  @response_expected[FUNCTION_SET_DECIBEL_CALLBACK_CONFIGURATION] = RESPONSE_EXPECTED_TRUE
  @response_expected[FUNCTION_GET_DECIBEL_CALLBACK_CONFIGURATION] = RESPONSE_EXPECTED_ALWAYS_TRUE
  @response_expected[FUNCTION_GET_SPECTRUM_LOW_LEVEL] = RESPONSE_EXPECTED_ALWAYS_TRUE
  @response_expected[FUNCTION_SET_SPECTRUM_CALLBACK_CONFIGURATION] = RESPONSE_EXPECTED_TRUE
  @response_expected[FUNCTION_GET_SPECTRUM_CALLBACK_CONFIGURATION] = RESPONSE_EXPECTED_ALWAYS_TRUE
  @response_expected[FUNCTION_SET_CONFIGURATION] = RESPONSE_EXPECTED_FALSE
  @response_expected[FUNCTION_GET_CONFIGURATION] = RESPONSE_EXPECTED_ALWAYS_TRUE
  @response_expected[FUNCTION_GET_SPITFP_ERROR_COUNT] = RESPONSE_EXPECTED_ALWAYS_TRUE
  @response_expected[FUNCTION_SET_BOOTLOADER_MODE] = RESPONSE_EXPECTED_ALWAYS_TRUE
  @response_expected[FUNCTION_GET_BOOTLOADER_MODE] = RESPONSE_EXPECTED_ALWAYS_TRUE
  @response_expected[FUNCTION_SET_WRITE_FIRMWARE_POINTER] = RESPONSE_EXPECTED_FALSE
  @response_expected[FUNCTION_WRITE_FIRMWARE] = RESPONSE_EXPECTED_ALWAYS_TRUE
  @response_expected[FUNCTION_SET_STATUS_LED_CONFIG] = RESPONSE_EXPECTED_FALSE
  @response_expected[FUNCTION_GET_STATUS_LED_CONFIG] = RESPONSE_EXPECTED_ALWAYS_TRUE
  @response_expected[FUNCTION_GET_CHIP_TEMPERATURE] = RESPONSE_EXPECTED_ALWAYS_TRUE
  @response_expected[FUNCTION_RESET] = RESPONSE_EXPECTED_FALSE
  @response_expected[FUNCTION_WRITE_UID] = RESPONSE_EXPECTED_FALSE
  @response_expected[FUNCTION_READ_UID] = RESPONSE_EXPECTED_ALWAYS_TRUE
  @response_expected[FUNCTION_GET_IDENTITY] = RESPONSE_EXPECTED_ALWAYS_TRUE

  @callback_formats[CALLBACK_DECIBEL] = [10, 'S']
  @callback_formats[CALLBACK_SPECTRUM_LOW_LEVEL] = [72, 'S S S30']

  @high_level_callbacks[CALLBACK_SPECTRUM] = [['stream_length', 'stream_chunk_offset', 'stream_chunk_data'], {'fixed_length' => nil, 'single_chunk' => false}, nil]
  @ipcon.add_device self
end

Public Instance Methods

get_bootloader_mode() click to toggle source

Returns the current bootloader mode, see BrickletSoundPressureLevel#set_bootloader_mode.

# File lib/tinkerforge/bricklet_sound_pressure_level.rb, line 289
def get_bootloader_mode
  check_validity

  send_request FUNCTION_GET_BOOTLOADER_MODE, [], '', 9, 'C'
end
get_chip_temperature() click to toggle source

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.

# File lib/tinkerforge/bricklet_sound_pressure_level.rb, line 347
def get_chip_temperature
  check_validity

  send_request FUNCTION_GET_CHIP_TEMPERATURE, [], '', 10, 's'
end
get_configuration() click to toggle source

Returns the configuration as set by BrickletSoundPressureLevel#set_configuration.

# File lib/tinkerforge/bricklet_sound_pressure_level.rb, line 250
def get_configuration
  check_validity

  send_request FUNCTION_GET_CONFIGURATION, [], '', 10, 'C C'
end
get_decibel() click to toggle source

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 BrickletSoundPressureLevel#set_configuration.

By default dB(A) will be used.

If you want to get the value periodically, it is recommended to use the CALLBACK_DECIBEL callback. You can set the callback configuration with BrickletSoundPressureLevel#set_decibel_callback_configuration.

# File lib/tinkerforge/bricklet_sound_pressure_level.rb, line 135
def get_decibel
  check_validity

  send_request FUNCTION_GET_DECIBEL, [], '', 10, 'S'
end
get_decibel_callback_configuration() click to toggle source

Returns the callback configuration as set by BrickletSoundPressureLevel#set_decibel_callback_configuration.

# File lib/tinkerforge/bricklet_sound_pressure_level.rb, line 173
def get_decibel_callback_configuration
  check_validity

  send_request FUNCTION_GET_DECIBEL_CALLBACK_CONFIGURATION, [], '', 18, 'L ? k S S'
end
get_identity() click to toggle source

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 :ref:`Isolator Bricklet <isolator_bricklet>` is always at position 'z'.

The device identifier numbers can be found :ref:`here <device_identifier>`. |device_identifier_constant|

# File lib/tinkerforge/bricklet_sound_pressure_level.rb, line 394
def get_identity
  send_request FUNCTION_GET_IDENTITY, [], '', 33, 'Z8 Z8 k C3 C3 S'
end
get_spectrum() click to toggle source

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

# File lib/tinkerforge/bricklet_sound_pressure_level.rb, line 416
def get_spectrum
  spectrum_length = nil # assigned in block
  spectrum_data = nil # assigned in block

  @stream_mutex.synchronize {
    ret = get_spectrum_low_level
    spectrum_length = ret[0]
    spectrum_chunk_offset = ret[1]
    spectrum_out_of_sync = spectrum_chunk_offset != 0
    spectrum_data = ret[2]

    while not spectrum_out_of_sync and spectrum_data.length < spectrum_length
      ret = get_spectrum_low_level
      spectrum_length = ret[0]
      spectrum_chunk_offset = ret[1]
      spectrum_out_of_sync = spectrum_chunk_offset != spectrum_data.length
      spectrum_data += ret[2]
    end

    if spectrum_out_of_sync # discard remaining stream to bring it back in-sync
      while spectrum_chunk_offset + 30 < spectrum_length
        ret = get_spectrum_low_level
        spectrum_length = ret[0]
        spectrum_chunk_offset = ret[1]
      end

      raise StreamOutOfSyncException, 'Spectrum stream is out-of-sync'
    end
  }

  spectrum_data[0, spectrum_length]
end
get_spectrum_callback_configuration() click to toggle source

Returns the callback configuration as set by BrickletSoundPressureLevel#get_spectrum_callback_configuration.

# File lib/tinkerforge/bricklet_sound_pressure_level.rb, line 216
def get_spectrum_callback_configuration
  check_validity

  send_request FUNCTION_GET_SPECTRUM_CALLBACK_CONFIGURATION, [], '', 12, 'L'
end
get_spectrum_low_level() click to toggle source

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

# File lib/tinkerforge/bricklet_sound_pressure_level.rb, line 197
def get_spectrum_low_level
  check_validity

  send_request FUNCTION_GET_SPECTRUM_LOW_LEVEL, [], '', 72, 'S S S30'
end
get_spitfp_error_count() click to toggle source

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.

# File lib/tinkerforge/bricklet_sound_pressure_level.rb, line 267
def get_spitfp_error_count
  check_validity

  send_request FUNCTION_GET_SPITFP_ERROR_COUNT, [], '', 24, 'L L L L'
end
get_status_led_config() click to toggle source

Returns the configuration as set by BrickletSoundPressureLevel#set_status_led_config

# File lib/tinkerforge/bricklet_sound_pressure_level.rb, line 335
def get_status_led_config
  check_validity

  send_request FUNCTION_GET_STATUS_LED_CONFIG, [], '', 9, 'C'
end
read_uid() click to toggle source

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

# File lib/tinkerforge/bricklet_sound_pressure_level.rb, line 378
def read_uid
  check_validity

  send_request FUNCTION_READ_UID, [], '', 12, 'L'
end
register_callback(id, &block) click to toggle source

Registers a callback with ID id to the block block.

# File lib/tinkerforge/bricklet_sound_pressure_level.rb, line 450
def register_callback(id, &block)
  callback = block
  @registered_callbacks[id] = callback
end
reset() click to toggle source

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!

# File lib/tinkerforge/bricklet_sound_pressure_level.rb, line 359
def reset
  check_validity

  send_request FUNCTION_RESET, [], '', 8, ''
end
set_bootloader_mode(mode) click to toggle source

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.

# File lib/tinkerforge/bricklet_sound_pressure_level.rb, line 282
def set_bootloader_mode(mode)
  check_validity

  send_request FUNCTION_SET_BOOTLOADER_MODE, [mode], 'C', 9, 'C'
end
set_configuration(fft_size, weighting) click to toggle source

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.

# File lib/tinkerforge/bricklet_sound_pressure_level.rb, line 243
def set_configuration(fft_size, weighting)
  check_validity

  send_request FUNCTION_SET_CONFIGURATION, [fft_size, weighting], 'C C', 8, ''
end
set_decibel_callback_configuration(period, value_has_to_change, option, min, max) click to toggle source

The period is the period with which the CALLBACK_DECIBEL 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 CALLBACK_DECIBEL 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.

# File lib/tinkerforge/bricklet_sound_pressure_level.rb, line 166
def set_decibel_callback_configuration(period, value_has_to_change, option, min, max)
  check_validity

  send_request FUNCTION_SET_DECIBEL_CALLBACK_CONFIGURATION, [period, value_has_to_change, option, min, max], 'L ? k S S', 8, ''
end
set_spectrum_callback_configuration(period) click to toggle source

The period is the period with which the CALLBACK_SPECTRUM 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.

# File lib/tinkerforge/bricklet_sound_pressure_level.rb, line 208
def set_spectrum_callback_configuration(period)
  check_validity

  send_request FUNCTION_SET_SPECTRUM_CALLBACK_CONFIGURATION, [period], 'L', 8, ''
end
set_status_led_config(config) click to toggle source

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.

# File lib/tinkerforge/bricklet_sound_pressure_level.rb, line 328
def set_status_led_config(config)
  check_validity

  send_request FUNCTION_SET_STATUS_LED_CONFIG, [config], 'C', 8, ''
end
set_write_firmware_pointer(pointer) click to toggle source

Sets the firmware pointer for BrickletSoundPressureLevel#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.

# File lib/tinkerforge/bricklet_sound_pressure_level.rb, line 301
def set_write_firmware_pointer(pointer)
  check_validity

  send_request FUNCTION_SET_WRITE_FIRMWARE_POINTER, [pointer], 'L', 8, ''
end
write_firmware(data) click to toggle source

Writes 64 Bytes of firmware at the position as written by BrickletSoundPressureLevel#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.

# File lib/tinkerforge/bricklet_sound_pressure_level.rb, line 315
def write_firmware(data)
  check_validity

  send_request FUNCTION_WRITE_FIRMWARE, [data], 'C64', 9, 'C'
end
write_uid(uid) click to toggle source

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.

# File lib/tinkerforge/bricklet_sound_pressure_level.rb, line 370
def write_uid(uid)
  check_validity

  send_request FUNCTION_WRITE_UID, [uid], 'L', 8, ''
end