Shell - Sound Pressure Level Bricklet¶

Simple¶

Download (example-simple.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 Sound Pressure Level Bricklet

# Get current decibel
tinkerforge call sound-pressure-level-bricklet $uid get-decibel

Callback¶

Download (example-callback.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 Sound Pressure Level Bricklet

# Handle incoming decibel callbacks
tinkerforge dispatch sound-pressure-level-bricklet $uid decibel &

# Set period for decibel callback to 1s (1000ms) without a threshold
tinkerforge call sound-pressure-level-bricklet $uid set-decibel-callback-configuration 1000 false threshold-option-off 0 0

echo "Press key to exit"; read dummy

kill -- -$$ # Stop callback dispatch in background

Threshold¶

Download (example-threshold.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 Sound Pressure Level Bricklet

# Handle incoming decibel callbacks
tinkerforge dispatch sound-pressure-level-bricklet $uid decibel &

# Configure threshold for decibel "greater than 60 dB(A)"
# with a debounce period of 1s (1000ms)
tinkerforge call sound-pressure-level-bricklet $uid set-decibel-callback-configuration 1000 false threshold-option-greater 600 0

echo "Press key to exit"; read dummy

kill -- -$$ # Stop callback dispatch in background

Command Structure¶

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

tinkerforge call sound-pressure-level-bricklet [<option>..] <uid> <function> [<argument>..]¶

Parameters:	<uid> – Type: String <function> – Type: String

The call command is used to call a function of the Sound Pressure Level 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 Sound Pressure Level Bricklet and exits

tinkerforge dispatch sound-pressure-level-bricklet [<option>..] <uid> <callback>¶

Parameters:	<uid> – Type: String <callback> – Type: String

The dispatch command is used to dispatch a callback of the Sound Pressure Level 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 Sound Pressure Level Bricklet and exits

tinkerforge call sound-pressure-level-bricklet <uid> <function> [<option>..] [<argument>..]¶

Parameters:	<uid> – Type: String <function> – Type: 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 sent and errors are silently ignored, because they cannot be detected.

tinkerforge dispatch sound-pressure-level-bricklet <uid> <callback> [<option>..]¶

Parameters:	<uid> – Type: String <callback> – Type: 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 sound-pressure-level-bricklet <uid> get-decibel¶

Output:	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 set-configuration.

By default dB(A) will be used.

If you want to get the value periodically, it is recommended to use the decibel callback. You can set the callback configuration with set-decibel-callback-configuration.

tinkerforge call sound-pressure-level-bricklet <uid> get-spectrum¶

Output:	spectrum – Type: Int Array, 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 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 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.

tinkerforge call sound-pressure-level-bricklet <uid> set-configuration <fft-size> <weighting>¶

Parameters:	<fft-size> – Type: Int, Range: See symbols, Default: 3 <weighting> – Type: Int, Range: See symbols, Default: 0
Output:	no output

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 following symbols are available for this function:

For <fft-size>:

• fft-size-128 = 0
• fft-size-256 = 1
• fft-size-512 = 2
• fft-size-1024 = 3

For <weighting>:

• weighting-a = 0
• weighting-b = 1
• weighting-c = 2
• weighting-d = 3
• weighting-z = 4
• weighting-itu-r-468 = 5

tinkerforge call sound-pressure-level-bricklet <uid> get-configuration¶

Output:	fft-size – Type: Int, Range: See symbols, Default: 3 weighting – Type: Int, Range: See symbols, Default: 0

Returns the configuration as set by set-configuration.

The following symbols are available for this function:

For fft-size:

• fft-size-128 = 0
• fft-size-256 = 1
• fft-size-512 = 2
• fft-size-1024 = 3

For weighting:

• weighting-a = 0
• weighting-b = 1
• weighting-c = 2
• weighting-d = 3
• weighting-z = 4
• weighting-itu-r-468 = 5

Advanced Functions¶

tinkerforge call sound-pressure-level-bricklet <uid> get-spitfp-error-count¶

Output:	error-count-ack-checksum – Type: Int, Range: [0 to 232 - 1] error-count-message-checksum – Type: Int, Range: [0 to 232 - 1] error-count-frame – Type: Int, Range: [0 to 232 - 1] error-count-overflow – Type: Int, 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.

tinkerforge call sound-pressure-level-bricklet <uid> set-status-led-config <config>¶

Parameters:	<config> – Type: Int, Range: See symbols, Default: 3
Output:	no output

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 symbols are available for this function:

For <config>:

• status-led-config-off = 0
• status-led-config-on = 1
• status-led-config-show-heartbeat = 2
• status-led-config-show-status = 3

tinkerforge call sound-pressure-level-bricklet <uid> get-status-led-config¶

Output:	config – Type: Int, Range: See symbols, Default: 3

Returns the configuration as set by set-status-led-config

The following symbols are available for this function:

For config:

• status-led-config-off = 0
• status-led-config-on = 1
• status-led-config-show-heartbeat = 2
• status-led-config-show-status = 3

tinkerforge call sound-pressure-level-bricklet <uid> get-chip-temperature¶

Output:	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.

tinkerforge call sound-pressure-level-bricklet <uid> reset¶

Output:	no output

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!

tinkerforge call sound-pressure-level-bricklet <uid> get-identity¶

Output:

uid – Type: String, Length: up to 8 connected-uid – Type: String, Length: up to 8 position – Type: Char, Range: [a to h, z] hardware-version – Type: Int Array, Length: 3 0: major – Type: Int, Range: [0 to 255] 1: minor – Type: Int, Range: [0 to 255] 2: revision – Type: Int, Range: [0 to 255] firmware-version – Type: Int Array, Length: 3 0: major – Type: Int, Range: [0 to 255] 1: minor – Type: Int, Range: [0 to 255] 2: revision – Type: Int, Range: [0 to 255] device-identifier – 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. 

Callback Configuration Functions¶

tinkerforge call sound-pressure-level-bricklet <uid> set-decibel-callback-configuration <period> <value-has-to-change> <option> <min> <max>¶

Parameters:	<period> – Type: Int, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0 <value-has-to-change> – Type: Bool, Default: false <option> – Type: Char, Range: See symbols, Default: x <min> – Type: Int, Unit: 1/10 dB, Range: [0 to 216 - 1], Default: 0 <max> – Type: Int, Unit: 1/10 dB, Range: [0 to 216 - 1], Default: 0
Output:	no output

The period is the period with which the 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 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.

The following symbols are available for this function:

For <option>:

• threshold-option-off = x
• threshold-option-outside = o
• threshold-option-inside = i
• threshold-option-smaller = <
• threshold-option-greater = >

tinkerforge call sound-pressure-level-bricklet <uid> get-decibel-callback-configuration¶

Output:	period – Type: Int, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0 value-has-to-change – Type: Bool, Default: false option – Type: Char, Range: See symbols, Default: x min – Type: Int, Unit: 1/10 dB, Range: [0 to 216 - 1], Default: 0 max – Type: Int, Unit: 1/10 dB, Range: [0 to 216 - 1], Default: 0

Returns the callback configuration as set by set-decibel-callback-configuration.

The following symbols are available for this function:

For option:

• threshold-option-off = x
• threshold-option-outside = o
• threshold-option-inside = i
• threshold-option-smaller = <
• threshold-option-greater = >

tinkerforge call sound-pressure-level-bricklet <uid> set-spectrum-callback-configuration <period>¶

Parameters:	<period> – Type: Int, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0
Output:	no output

The period is the period with which the 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.

tinkerforge call sound-pressure-level-bricklet <uid> get-spectrum-callback-configuration¶

Output:	period – Type: Int, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0

Returns the callback configuration as set by get-spectrum-callback-configuration.

Callbacks¶

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

tinkerforge dispatch sound-pressure-level-bricklet <uid> example

The available callbacks are described below.

tinkerforge dispatch sound-pressure-level-bricklet <uid> decibel¶

Output:	decibel – Type: Int, Unit: 1/10 dB, Range: [0 to 120]

This callback is triggered periodically according to the configuration set by set-decibel-callback-configuration.

The parameter is the same as get-decibel.

tinkerforge dispatch sound-pressure-level-bricklet <uid> spectrum¶

Output:	spectrum – Type: Int Array, Length: variable, Unit: ? dB, Range: [0 to 216 - 1]

This callback is triggered periodically according to the configuration set by set-spectrum-callback-configuration.

The parameter is the same as get-spectrum.

Note

If reconstructing the value fails, the callback is triggered with None for spectrum.

Internal Functions¶

Internal functions are used for maintenance tasks such as flashing a new firmware of changing the UID of a Bricklet. These task should be performed using Brick Viewer instead of using the internal functions directly.

tinkerforge call sound-pressure-level-bricklet <uid> set-bootloader-mode <mode>¶

Parameters:	<mode> – Type: Int, Range: See symbols
Output:	status – Type: Int, Range: See symbols

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 symbols are available for this function:

For <mode>:

• bootloader-mode-bootloader = 0
• bootloader-mode-firmware = 1
• bootloader-mode-bootloader-wait-for-reboot = 2
• bootloader-mode-firmware-wait-for-reboot = 3
• bootloader-mode-firmware-wait-for-erase-and-reboot = 4

For status:

• bootloader-status-ok = 0
• bootloader-status-invalid-mode = 1
• bootloader-status-no-change = 2
• bootloader-status-entry-function-not-present = 3
• bootloader-status-device-identifier-incorrect = 4
• bootloader-status-crc-mismatch = 5

tinkerforge call sound-pressure-level-bricklet <uid> get-bootloader-mode¶

Output:	mode – Type: Int, Range: See symbols

Returns the current bootloader mode, see set-bootloader-mode.

The following symbols are available for this function:

For mode:

• bootloader-mode-bootloader = 0
• bootloader-mode-firmware = 1
• bootloader-mode-bootloader-wait-for-reboot = 2
• bootloader-mode-firmware-wait-for-reboot = 3
• bootloader-mode-firmware-wait-for-erase-and-reboot = 4

tinkerforge call sound-pressure-level-bricklet <uid> set-write-firmware-pointer <pointer>¶

Parameters:	<pointer> – Type: Int, Unit: 1 B, Range: [0 to 232 - 1]
Output:	no output

Sets the firmware pointer for 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.

tinkerforge call sound-pressure-level-bricklet <uid> write-firmware <data>¶

Parameters:	<data> – Type: Int Array, Length: 64, Range: [0 to 255]
Output:	status – Type: Int, Range: [0 to 255]

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

tinkerforge call sound-pressure-level-bricklet <uid> write-uid <uid>¶

Parameters:	<uid> – Type: Int, Range: [0 to 232 - 1]
Output:	no output

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.

tinkerforge call sound-pressure-level-bricklet <uid> read-uid¶

Output:	uid – Type: Int, Range: [0 to 232 - 1]

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