Shell - Barometer Bricklet 2.0

This is the description of the Shell API bindings for the Barometer Bricklet 2.0. General information and technical specifications for the Barometer Bricklet 2.0 are summarized in its hardware description.

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

Examples

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

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 Barometer Bricklet 2.0

# Get current air pressure
tinkerforge call barometer-v2-bricklet $uid get-air-pressure

# Get current altitude
tinkerforge call barometer-v2-bricklet $uid get-altitude

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 Barometer Bricklet 2.0

# Handle incoming air pressure callbacks
tinkerforge dispatch barometer-v2-bricklet $uid air-pressure &

# Set period for air pressure callback to 1s (1000ms) without a threshold
tinkerforge call barometer-v2-bricklet $uid set-air-pressure-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 Barometer Bricklet 2.0

# Handle incoming air pressure callbacks
tinkerforge dispatch barometer-v2-bricklet $uid air-pressure\
 --execute "echo Air Pressure: {air_pressure}/1000 mbar. Enjoy the potentially good weather!" &

# Configure threshold for air pressure "greater than 1025 mbar"
# with a debounce period of 1s (1000ms)
tinkerforge call barometer-v2-bricklet $uid set-air-pressure-callback-configuration 1000 false threshold-option-greater 1025000 0

echo "Press key to exit"; read dummy

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

API

Possible exit codes for all tinkerforge commands are:

  • 1: interrupted (ctrl+c)
  • 2: syntax error
  • 21: Python 2.5 or newer is required
  • 22: Python argparse module is missing
  • 23: socket error
  • 24: other exception
  • 25: invalid placeholder in format string
  • 26: authentication error
  • 201: timeout occurred
  • 209: invalid argument value
  • 210: function is not supported
  • 211: unknown error

Command Structure

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

tinkerforge call barometer-v2-bricklet [<option>..] <uid> <function> [<argument>..]
Parameters:
  • <uid> -- string
  • <function> -- string

The call command is used to call a function of the Barometer Bricklet 2.0. 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 Barometer Bricklet 2.0 and exits
tinkerforge dispatch barometer-v2-bricklet [<option>..] <uid> <callback>
Parameters:
  • <uid> -- string
  • <callback> -- string

The dispatch command is used to dispatch a callback of the Barometer Bricklet 2.0. 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 Barometer Bricklet 2.0 and exits
tinkerforge call barometer-v2-bricklet <uid> <function> [<option>..] [<argument>..]
Parameters:
  • <uid> -- string
  • <function> -- 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 send and errors are silently ignored, because they cannot be detected.

tinkerforge dispatch barometer-v2-bricklet <uid> <callback> [<option>..]
Parameters:
  • <uid> -- string
  • <callback> -- 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 barometer-v2-bricklet <uid> get-air-pressure
Output:
  • air-pressure -- int

Returns the measured air pressure. The value has a range of 260000 to 1260000 and is given in mbar/1000, i.e. a value of 1001092 means that an air pressure of 1001.092 mbar is measured.

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

tinkerforge call barometer-v2-bricklet <uid> get-altitude
Output:
  • altitude -- int

Returns the relative altitude of the air pressure sensor. The value is given in mm and is calculated based on the difference between the current air pressure and the reference air pressure that can be set with set-reference-air-pressure.

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

tinkerforge call barometer-v2-bricklet <uid> get-temperature
Output:
  • temperature -- int

Returns the temperature of the air pressure sensor. The value has a range of -4000 to 8500 and is given in °C/100, i.e. a value of 2007 means that a temperature of 20.07 °C is measured.

This temperature is used internally for temperature compensation of the air pressure measurement. It is not as accurate as the temperature measured by the Temperature Bricklet 2.0 or the Temperature IR Bricklet 2.0.

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

tinkerforge call barometer-v2-bricklet <uid> set-moving-average-configuration <moving-average-length-air-pressure> <moving-average-length-temperature>
Parameters:
  • <moving-average-length-air-pressure> -- int
  • <moving-average-length-temperature> -- int
Output:

no output

Sets the length of a moving averaging for the air pressure and temperature measurements.

Setting the length to 1 will turn the averaging off. With less averaging, there is more noise on the data.

The range for the averaging is 1-1000.

If you want to do long term measurements the longest moving average will give the cleanest results.

The default value is 100.

tinkerforge call barometer-v2-bricklet <uid> get-moving-average-configuration
Output:
  • moving-average-length-air-pressure -- int
  • moving-average-length-temperature -- int

Returns the moving average configuration as set by set-moving-average-configuration.

tinkerforge call barometer-v2-bricklet <uid> set-reference-air-pressure <air-pressure>
Parameters:
  • <air-pressure> -- int
Output:

no output

Sets the reference air pressure in mbar/1000 for the altitude calculation. Valid values are between 260000 and 1260000. Setting the reference to the current air pressure results in a calculated altitude of 0mm. Passing 0 is a shortcut for passing the current air pressure as reference.

Well known reference values are the Q codes QNH and QFE used in aviation.

The default value is 1013.25mbar.

tinkerforge call barometer-v2-bricklet <uid> get-reference-air-pressure
Output:
  • air-pressure -- int

Returns the reference air pressure as set by set-reference-air-pressure.

Advanced Functions

tinkerforge call barometer-v2-bricklet <uid> set-calibration <measured-air-pressure> <actual-air-pressure>
Parameters:
  • <measured-air-pressure> -- int
  • <actual-air-pressure> -- int
Output:

no output

Sets the one point calibration (OPC) values for the air pressure measurement.

Before the Bricklet can be calibrated any previous calibration has to be removed by setting measured air pressure and actual air pressure to 0.

Then the current air pressure has to be measured using the Bricklet (measured air pressure) and with and accurate reference barometer (actual air pressure) at the same time and passed to this function in mbar/1000.

After proper calibration the air pressure measurement can achieve an accuracy up to 0.2 mbar.

The calibration is saved in the EEPROM of the Bricklet and only needs to be configured once.

tinkerforge call barometer-v2-bricklet <uid> get-calibration
Output:
  • measured-air-pressure -- int
  • actual-air-pressure -- int

Returns the air pressure one point calibration values as set by set-calibration.

tinkerforge call barometer-v2-bricklet <uid> set-sensor-configuration <data-rate> <air-pressure-low-pass-filter>
Parameters:
  • <data-rate> -- int (has symbols)
  • <air-pressure-low-pass-filter> -- int (has symbols)
Output:

no output

Configures the data rate and air pressure low pass filter. The low pass filter cut-off frequency (if enabled) can be set to 1/9th or 1/20th of the configure data rate to decrease the noise on the air pressure data.

The low pass filter configuration only applies to the air pressure measurement. There is no low pass filter for the temperature measurement.

A higher data rate will result in a less precise temperature because of self-heating of the sensor. If the accuracy of the temperature reading is important to you, we would recommend the 1Hz data rate.

The default values are 50Hz data rate and 1/9th low pass filter.

The following symbols are available for this function:

  • data-rate-off = 0, for <data-rate>
  • data-rate-1hz = 1, for <data-rate>
  • data-rate-10hz = 2, for <data-rate>
  • data-rate-25hz = 3, for <data-rate>
  • data-rate-50hz = 4, for <data-rate>
  • data-rate-75hz = 5, for <data-rate>
  • low-pass-filter-off = 0, for <air-pressure-low-pass-filter>
  • low-pass-filter-1-9th = 1, for <air-pressure-low-pass-filter>
  • low-pass-filter-1-20th = 2, for <air-pressure-low-pass-filter>
tinkerforge call barometer-v2-bricklet <uid> get-sensor-configuration
Output:
  • data-rate -- int (has symbols)
  • air-pressure-low-pass-filter -- int (has symbols)

Returns the sensor configuration as set by set-sensor-configuration.

The following symbols are available for this function:

  • data-rate-off = 0, for data-rate
  • data-rate-1hz = 1, for data-rate
  • data-rate-10hz = 2, for data-rate
  • data-rate-25hz = 3, for data-rate
  • data-rate-50hz = 4, for data-rate
  • data-rate-75hz = 5, for data-rate
  • low-pass-filter-off = 0, for air-pressure-low-pass-filter
  • low-pass-filter-1-9th = 1, for air-pressure-low-pass-filter
  • low-pass-filter-1-20th = 2, for air-pressure-low-pass-filter
tinkerforge call barometer-v2-bricklet <uid> get-spitfp-error-count
Output:
  • error-count-ack-checksum -- int
  • error-count-message-checksum -- int
  • error-count-frame -- int
  • error-count-overflow -- int

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 barometer-v2-bricklet <uid> set-bootloader-mode <mode>
Parameters:
  • <mode> -- int (has symbols)
Output:
  • status -- int (has 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:

  • bootloader-mode-bootloader = 0, for <mode>
  • bootloader-mode-firmware = 1, for <mode>
  • bootloader-mode-bootloader-wait-for-reboot = 2, for <mode>
  • bootloader-mode-firmware-wait-for-reboot = 3, for <mode>
  • bootloader-mode-firmware-wait-for-erase-and-reboot = 4, for <mode>
  • bootloader-status-ok = 0, for status
  • bootloader-status-invalid-mode = 1, for status
  • bootloader-status-no-change = 2, for status
  • bootloader-status-entry-function-not-present = 3, for status
  • bootloader-status-device-identifier-incorrect = 4, for status
  • bootloader-status-crc-mismatch = 5, for status
tinkerforge call barometer-v2-bricklet <uid> get-bootloader-mode
Output:
  • mode -- int (has symbols)

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

The following symbols are available for this function:

  • bootloader-mode-bootloader = 0, for mode
  • bootloader-mode-firmware = 1, for mode
  • bootloader-mode-bootloader-wait-for-reboot = 2, for mode
  • bootloader-mode-firmware-wait-for-reboot = 3, for mode
  • bootloader-mode-firmware-wait-for-erase-and-reboot = 4, for mode
tinkerforge call barometer-v2-bricklet <uid> set-write-firmware-pointer <pointer>
Parameters:
  • <pointer> -- int
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 barometer-v2-bricklet <uid> write-firmware <data>
Parameters:
  • <data> -- int,int,..61x..,int
Output:
  • status -- int

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 barometer-v2-bricklet <uid> set-status-led-config <config>
Parameters:
  • <config> -- int (has symbols)
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:

  • status-led-config-off = 0, for <config>
  • status-led-config-on = 1, for <config>
  • status-led-config-show-heartbeat = 2, for <config>
  • status-led-config-show-status = 3, for <config>
tinkerforge call barometer-v2-bricklet <uid> get-status-led-config
Output:
  • config -- int (has symbols)

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

The following symbols are available for this function:

  • status-led-config-off = 0, for config
  • status-led-config-on = 1, for config
  • status-led-config-show-heartbeat = 2, for config
  • status-led-config-show-status = 3, for config
tinkerforge call barometer-v2-bricklet <uid> get-chip-temperature
Output:
  • temperature -- int

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.

tinkerforge call barometer-v2-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 barometer-v2-bricklet <uid> write-uid <uid>
Parameters:
  • <uid> -- int
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 barometer-v2-bricklet <uid> read-uid
Output:
  • uid -- int

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

tinkerforge call barometer-v2-bricklet <uid> get-identity
Output:
  • uid -- string
  • connected-uid -- string
  • position -- char
  • hardware-version -- int,int,int
  • firmware-version -- int,int,int
  • device-identifier -- int (has symbols)

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

Callback Configuration Functions

tinkerforge call barometer-v2-bricklet <uid> set-air-pressure-callback-configuration <period> <value-has-to-change> <option> <min> <max>
Parameters:
  • <period> -- int
  • <value-has-to-change> -- bool
  • <option> -- char (has symbols)
  • <min> -- int
  • <max> -- int
Output:

no output

The period in ms is the period with which the air-pressure 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 air-pressure 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 symbols are available for this function:

  • threshold-option-off = x, for <option>
  • threshold-option-outside = o, for <option>
  • threshold-option-inside = i, for <option>
  • threshold-option-smaller = <, for <option>
  • threshold-option-greater = >, for <option>
tinkerforge call barometer-v2-bricklet <uid> get-air-pressure-callback-configuration
Output:
  • period -- int
  • value-has-to-change -- bool
  • option -- char (has symbols)
  • min -- int
  • max -- int

Returns the callback configuration as set by set-air-pressure-callback-configuration.

The following symbols are available for this function:

  • threshold-option-off = x, for option
  • threshold-option-outside = o, for option
  • threshold-option-inside = i, for option
  • threshold-option-smaller = <, for option
  • threshold-option-greater = >, for option
tinkerforge call barometer-v2-bricklet <uid> set-altitude-callback-configuration <period> <value-has-to-change> <option> <min> <max>
Parameters:
  • <period> -- int
  • <value-has-to-change> -- bool
  • <option> -- char (has symbols)
  • <min> -- int
  • <max> -- int
Output:

no output

The period in ms is the period with which the altitude 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 altitude 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 symbols are available for this function:

  • threshold-option-off = x, for <option>
  • threshold-option-outside = o, for <option>
  • threshold-option-inside = i, for <option>
  • threshold-option-smaller = <, for <option>
  • threshold-option-greater = >, for <option>
tinkerforge call barometer-v2-bricklet <uid> get-altitude-callback-configuration
Output:
  • period -- int
  • value-has-to-change -- bool
  • option -- char (has symbols)
  • min -- int
  • max -- int

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

The following symbols are available for this function:

  • threshold-option-off = x, for option
  • threshold-option-outside = o, for option
  • threshold-option-inside = i, for option
  • threshold-option-smaller = <, for option
  • threshold-option-greater = >, for option
tinkerforge call barometer-v2-bricklet <uid> set-temperature-callback-configuration <period> <value-has-to-change> <option> <min> <max>
Parameters:
  • <period> -- int
  • <value-has-to-change> -- bool
  • <option> -- char (has symbols)
  • <min> -- int
  • <max> -- int
Output:

no output

The period in ms is the period with which the temperature 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 temperature 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 symbols are available for this function:

  • threshold-option-off = x, for <option>
  • threshold-option-outside = o, for <option>
  • threshold-option-inside = i, for <option>
  • threshold-option-smaller = <, for <option>
  • threshold-option-greater = >, for <option>
tinkerforge call barometer-v2-bricklet <uid> get-temperature-callback-configuration
Output:
  • period -- int
  • value-has-to-change -- bool
  • option -- char (has symbols)
  • min -- int
  • max -- int

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

The following symbols are available for this function:

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

Callbacks

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

tinkerforge dispatch barometer-v2-bricklet <uid> example

The available callbacks 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.

tinkerforge dispatch barometer-v2-bricklet <uid> air-pressure
Output:
  • air-pressure -- int

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

The parameter is the same as get-air-pressure.

tinkerforge dispatch barometer-v2-bricklet <uid> altitude
Output:
  • altitude -- int

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

The parameter is the same as get-altitude.

tinkerforge dispatch barometer-v2-bricklet <uid> temperature
Output:
  • temperature -- int

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

The parameter is the same as get-temperature.