Delphi/Lazarus - Barometer Bricklet 2.0

This is the description of the Delphi/Lazarus 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 Delphi/Lazarus API bindings is part of their general description.

Examples

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

Simple

Download (ExampleSimple.pas)

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program ExampleSimple;

{$ifdef MSWINDOWS}{$apptype CONSOLE}{$endif}
{$ifdef FPC}{$mode OBJFPC}{$H+}{$endif}

uses
  SysUtils, IPConnection, BrickletBarometerV2;

type
  TExample = class
  private
    ipcon: TIPConnection;
    b: TBrickletBarometerV2;
  public
    procedure Execute;
  end;

const
  HOST = 'localhost';
  PORT = 4223;
  UID = 'XYZ'; { Change XYZ to the UID of your Barometer Bricklet 2.0 }

var
  e: TExample;

procedure TExample.Execute;
var airPressure, altitude: longint;
begin
  { Create IP connection }
  ipcon := TIPConnection.Create;

  { Create device object }
  b := TBrickletBarometerV2.Create(UID, ipcon);

  { Connect to brickd }
  ipcon.Connect(HOST, PORT);
  { Don't use device before ipcon is connected }

  { Get current air pressure }
  airPressure := b.GetAirPressure;
  WriteLn(Format('Air Pressure: %f mbar', [airPressure/1000.0]));

  { Get current altitude }
  altitude := b.GetAltitude;
  WriteLn(Format('Altitude: %f m', [altitude/1000.0]));

  WriteLn('Press key to exit');
  ReadLn;
  ipcon.Destroy; { Calls ipcon.Disconnect internally }
end;

begin
  e := TExample.Create;
  e.Execute;
  e.Destroy;
end.

Callback

Download (ExampleCallback.pas)

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program ExampleCallback;

{$ifdef MSWINDOWS}{$apptype CONSOLE}{$endif}
{$ifdef FPC}{$mode OBJFPC}{$H+}{$endif}

uses
  SysUtils, IPConnection, BrickletBarometerV2;

type
  TExample = class
  private
    ipcon: TIPConnection;
    b: TBrickletBarometerV2;
  public
    procedure AirPressureCB(sender: TBrickletBarometerV2; const airPressure: longint);
    procedure Execute;
  end;

const
  HOST = 'localhost';
  PORT = 4223;
  UID = 'XYZ'; { Change XYZ to the UID of your Barometer Bricklet 2.0 }

var
  e: TExample;

{ Callback procedure for air pressure callback }
procedure TExample.AirPressureCB(sender: TBrickletBarometerV2;
                                 const airPressure: longint);
begin
  WriteLn(Format('Air Pressure: %f mbar', [airPressure/1000.0]));
end;

procedure TExample.Execute;
begin
  { Create IP connection }
  ipcon := TIPConnection.Create;

  { Create device object }
  b := TBrickletBarometerV2.Create(UID, ipcon);

  { Connect to brickd }
  ipcon.Connect(HOST, PORT);
  { Don't use device before ipcon is connected }

  { Register air pressure callback to procedure AirPressureCB }
  b.OnAirPressure := {$ifdef FPC}@{$endif}AirPressureCB;

  { Set period for air pressure callback to 1s (1000ms) without a threshold }
  b.SetAirPressureCallbackConfiguration(1000, false, 'x', 0, 0);

  WriteLn('Press key to exit');
  ReadLn;
  ipcon.Destroy; { Calls ipcon.Disconnect internally }
end;

begin
  e := TExample.Create;
  e.Execute;
  e.Destroy;
end.

Threshold

Download (ExampleThreshold.pas)

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program ExampleThreshold;

{$ifdef MSWINDOWS}{$apptype CONSOLE}{$endif}
{$ifdef FPC}{$mode OBJFPC}{$H+}{$endif}

uses
  SysUtils, IPConnection, BrickletBarometerV2;

type
  TExample = class
  private
    ipcon: TIPConnection;
    b: TBrickletBarometerV2;
  public
    procedure AirPressureCB(sender: TBrickletBarometerV2; const airPressure: longint);
    procedure Execute;
  end;

const
  HOST = 'localhost';
  PORT = 4223;
  UID = 'XYZ'; { Change XYZ to the UID of your Barometer Bricklet 2.0 }

var
  e: TExample;

{ Callback procedure for air pressure callback }
procedure TExample.AirPressureCB(sender: TBrickletBarometerV2;
                                 const airPressure: longint);
begin
  WriteLn(Format('Air Pressure: %f mbar', [airPressure/1000.0]));
  WriteLn('Enjoy the potentially good weather!');
end;

procedure TExample.Execute;
begin
  { Create IP connection }
  ipcon := TIPConnection.Create;

  { Create device object }
  b := TBrickletBarometerV2.Create(UID, ipcon);

  { Connect to brickd }
  ipcon.Connect(HOST, PORT);
  { Don't use device before ipcon is connected }

  { Register air pressure callback to procedure AirPressureCB }
  b.OnAirPressure := {$ifdef FPC}@{$endif}AirPressureCB;

  { Configure threshold for air pressure "greater than 1025 mbar"
    with a debounce period of 1s (1000ms) }
  b.SetAirPressureCallbackConfiguration(1000, false, '>', 1025*1000, 0);

  WriteLn('Press key to exit');
  ReadLn;
  ipcon.Destroy; { Calls ipcon.Disconnect internally }
end;

begin
  e := TExample.Create;
  e.Execute;
  e.Destroy;
end.

API

Since Delphi does not support multiple return values directly, we use the out keyword to return multiple values from a function.

All functions and procedures listed below are thread-safe.

Basic Functions

constructor TBrickletBarometerV2.Create(const uid: string; ipcon: TIPConnection)

Creates an object with the unique device ID uid:

barometerV2 := TBrickletBarometerV2.Create('YOUR_DEVICE_UID', ipcon);

This object can then be used after the IP Connection is connected (see examples above).

function TBrickletBarometerV2.GetAirPressure: longint

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 OnAirPressure callback. You can set the callback configuration with SetAirPressureCallbackConfiguration.

function TBrickletBarometerV2.GetAltitude: longint

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 SetReferenceAirPressure.

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

function TBrickletBarometerV2.GetTemperature: longint

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 OnTemperature callback. You can set the callback configuration with SetTemperatureCallbackConfiguration.

procedure TBrickletBarometerV2.SetMovingAverageConfiguration(const movingAverageLengthAirPressure: word; const movingAverageLengthTemperature: word)

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.

procedure TBrickletBarometerV2.GetMovingAverageConfiguration(out movingAverageLengthAirPressure: word; out movingAverageLengthTemperature: word)

Returns the moving average configuration as set by SetMovingAverageConfiguration.

procedure TBrickletBarometerV2.SetReferenceAirPressure(const airPressure: longint)

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.

function TBrickletBarometerV2.GetReferenceAirPressure: longint

Returns the reference air pressure as set by SetReferenceAirPressure.

Advanced Functions

procedure TBrickletBarometerV2.SetCalibration(const measuredAirPressure: longint; const actualAirPressure: longint)

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.

procedure TBrickletBarometerV2.GetCalibration(out measuredAirPressure: longint; out actualAirPressure: longint)

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

procedure TBrickletBarometerV2.SetSensorConfiguration(const dataRate: byte; const airPressureLowPassFilter: byte)

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 constants are available for this function:

  • BRICKLET_BAROMETER_V2_DATA_RATE_OFF = 0
  • BRICKLET_BAROMETER_V2_DATA_RATE_1HZ = 1
  • BRICKLET_BAROMETER_V2_DATA_RATE_10HZ = 2
  • BRICKLET_BAROMETER_V2_DATA_RATE_25HZ = 3
  • BRICKLET_BAROMETER_V2_DATA_RATE_50HZ = 4
  • BRICKLET_BAROMETER_V2_DATA_RATE_75HZ = 5
  • BRICKLET_BAROMETER_V2_LOW_PASS_FILTER_OFF = 0
  • BRICKLET_BAROMETER_V2_LOW_PASS_FILTER_1_9TH = 1
  • BRICKLET_BAROMETER_V2_LOW_PASS_FILTER_1_20TH = 2
procedure TBrickletBarometerV2.GetSensorConfiguration(out dataRate: byte; out airPressureLowPassFilter: byte)

Returns the sensor configuration as set by SetSensorConfiguration.

The following constants are available for this function:

  • BRICKLET_BAROMETER_V2_DATA_RATE_OFF = 0
  • BRICKLET_BAROMETER_V2_DATA_RATE_1HZ = 1
  • BRICKLET_BAROMETER_V2_DATA_RATE_10HZ = 2
  • BRICKLET_BAROMETER_V2_DATA_RATE_25HZ = 3
  • BRICKLET_BAROMETER_V2_DATA_RATE_50HZ = 4
  • BRICKLET_BAROMETER_V2_DATA_RATE_75HZ = 5
  • BRICKLET_BAROMETER_V2_LOW_PASS_FILTER_OFF = 0
  • BRICKLET_BAROMETER_V2_LOW_PASS_FILTER_1_9TH = 1
  • BRICKLET_BAROMETER_V2_LOW_PASS_FILTER_1_20TH = 2
function TBrickletBarometerV2.GetAPIVersion: array [0..2] of byte

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.

function TBrickletBarometerV2.GetResponseExpected(const functionId: byte): 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.

procedure TBrickletBarometerV2.SetResponseExpected(const functionId: byte; const 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:

  • BRICKLET_BAROMETER_V2_FUNCTION_SET_AIR_PRESSURE_CALLBACK_CONFIGURATION = 2
  • BRICKLET_BAROMETER_V2_FUNCTION_SET_ALTITUDE_CALLBACK_CONFIGURATION = 6
  • BRICKLET_BAROMETER_V2_FUNCTION_SET_TEMPERATURE_CALLBACK_CONFIGURATION = 10
  • BRICKLET_BAROMETER_V2_FUNCTION_SET_MOVING_AVERAGE_CONFIGURATION = 13
  • BRICKLET_BAROMETER_V2_FUNCTION_SET_REFERENCE_AIR_PRESSURE = 15
  • BRICKLET_BAROMETER_V2_FUNCTION_SET_CALIBRATION = 17
  • BRICKLET_BAROMETER_V2_FUNCTION_SET_SENSOR_CONFIGURATION = 19
  • BRICKLET_BAROMETER_V2_FUNCTION_SET_WRITE_FIRMWARE_POINTER = 237
  • BRICKLET_BAROMETER_V2_FUNCTION_SET_STATUS_LED_CONFIG = 239
  • BRICKLET_BAROMETER_V2_FUNCTION_RESET = 243
  • BRICKLET_BAROMETER_V2_FUNCTION_WRITE_UID = 248
procedure TBrickletBarometerV2.SetResponseExpectedAll(const responseExpected: boolean)

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

procedure TBrickletBarometerV2.GetSPITFPErrorCount(out errorCountAckChecksum: longword; out errorCountMessageChecksum: longword; out errorCountFrame: longword; out errorCountOverflow: longword)

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.

function TBrickletBarometerV2.SetBootloaderMode(const mode: byte): 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:

  • BRICKLET_BAROMETER_V2_BOOTLOADER_MODE_BOOTLOADER = 0
  • BRICKLET_BAROMETER_V2_BOOTLOADER_MODE_FIRMWARE = 1
  • BRICKLET_BAROMETER_V2_BOOTLOADER_MODE_BOOTLOADER_WAIT_FOR_REBOOT = 2
  • BRICKLET_BAROMETER_V2_BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_REBOOT = 3
  • BRICKLET_BAROMETER_V2_BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_ERASE_AND_REBOOT = 4
  • BRICKLET_BAROMETER_V2_BOOTLOADER_STATUS_OK = 0
  • BRICKLET_BAROMETER_V2_BOOTLOADER_STATUS_INVALID_MODE = 1
  • BRICKLET_BAROMETER_V2_BOOTLOADER_STATUS_NO_CHANGE = 2
  • BRICKLET_BAROMETER_V2_BOOTLOADER_STATUS_ENTRY_FUNCTION_NOT_PRESENT = 3
  • BRICKLET_BAROMETER_V2_BOOTLOADER_STATUS_DEVICE_IDENTIFIER_INCORRECT = 4
  • BRICKLET_BAROMETER_V2_BOOTLOADER_STATUS_CRC_MISMATCH = 5
function TBrickletBarometerV2.GetBootloaderMode: byte

Returns the current bootloader mode, see SetBootloaderMode.

The following constants are available for this function:

  • BRICKLET_BAROMETER_V2_BOOTLOADER_MODE_BOOTLOADER = 0
  • BRICKLET_BAROMETER_V2_BOOTLOADER_MODE_FIRMWARE = 1
  • BRICKLET_BAROMETER_V2_BOOTLOADER_MODE_BOOTLOADER_WAIT_FOR_REBOOT = 2
  • BRICKLET_BAROMETER_V2_BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_REBOOT = 3
  • BRICKLET_BAROMETER_V2_BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_ERASE_AND_REBOOT = 4
procedure TBrickletBarometerV2.SetWriteFirmwarePointer(const pointer: longword)

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.

function TBrickletBarometerV2.WriteFirmware(const data: array [0..63] of byte): 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.

procedure TBrickletBarometerV2.SetStatusLEDConfig(const 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:

  • BRICKLET_BAROMETER_V2_STATUS_LED_CONFIG_OFF = 0
  • BRICKLET_BAROMETER_V2_STATUS_LED_CONFIG_ON = 1
  • BRICKLET_BAROMETER_V2_STATUS_LED_CONFIG_SHOW_HEARTBEAT = 2
  • BRICKLET_BAROMETER_V2_STATUS_LED_CONFIG_SHOW_STATUS = 3
function TBrickletBarometerV2.GetStatusLEDConfig: byte

Returns the configuration as set by SetStatusLEDConfig

The following constants are available for this function:

  • BRICKLET_BAROMETER_V2_STATUS_LED_CONFIG_OFF = 0
  • BRICKLET_BAROMETER_V2_STATUS_LED_CONFIG_ON = 1
  • BRICKLET_BAROMETER_V2_STATUS_LED_CONFIG_SHOW_HEARTBEAT = 2
  • BRICKLET_BAROMETER_V2_STATUS_LED_CONFIG_SHOW_STATUS = 3
function TBrickletBarometerV2.GetChipTemperature: smallint

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.

procedure TBrickletBarometerV2.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!

procedure TBrickletBarometerV2.WriteUID(const uid: longword)

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.

function TBrickletBarometerV2.ReadUID: longword

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

procedure TBrickletBarometerV2.GetIdentity(out uid: string; out connectedUid: string; out position: char; out hardwareVersion: array [0..2] of byte; out firmwareVersion: array [0..2] of byte; out deviceIdentifier: word)

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

procedure TBrickletBarometerV2.SetAirPressureCallbackConfiguration(const period: longword; const valueHasToChange: boolean; const option: char; const min: longint; const max: longint)

The period in ms is the period with which the OnAirPressure 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 OnAirPressure 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:

  • BRICKLET_BAROMETER_V2_THRESHOLD_OPTION_OFF = 'x'
  • BRICKLET_BAROMETER_V2_THRESHOLD_OPTION_OUTSIDE = 'o'
  • BRICKLET_BAROMETER_V2_THRESHOLD_OPTION_INSIDE = 'i'
  • BRICKLET_BAROMETER_V2_THRESHOLD_OPTION_SMALLER = '<'
  • BRICKLET_BAROMETER_V2_THRESHOLD_OPTION_GREATER = '>'
procedure TBrickletBarometerV2.GetAirPressureCallbackConfiguration(out period: longword; out valueHasToChange: boolean; out option: char; out min: longint; out max: longint)

Returns the callback configuration as set by SetAirPressureCallbackConfiguration.

The following constants are available for this function:

  • BRICKLET_BAROMETER_V2_THRESHOLD_OPTION_OFF = 'x'
  • BRICKLET_BAROMETER_V2_THRESHOLD_OPTION_OUTSIDE = 'o'
  • BRICKLET_BAROMETER_V2_THRESHOLD_OPTION_INSIDE = 'i'
  • BRICKLET_BAROMETER_V2_THRESHOLD_OPTION_SMALLER = '<'
  • BRICKLET_BAROMETER_V2_THRESHOLD_OPTION_GREATER = '>'
procedure TBrickletBarometerV2.SetAltitudeCallbackConfiguration(const period: longword; const valueHasToChange: boolean; const option: char; const min: longint; const max: longint)

The period in ms is the period with which the OnAltitude 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 OnAltitude 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:

  • BRICKLET_BAROMETER_V2_THRESHOLD_OPTION_OFF = 'x'
  • BRICKLET_BAROMETER_V2_THRESHOLD_OPTION_OUTSIDE = 'o'
  • BRICKLET_BAROMETER_V2_THRESHOLD_OPTION_INSIDE = 'i'
  • BRICKLET_BAROMETER_V2_THRESHOLD_OPTION_SMALLER = '<'
  • BRICKLET_BAROMETER_V2_THRESHOLD_OPTION_GREATER = '>'
procedure TBrickletBarometerV2.GetAltitudeCallbackConfiguration(out period: longword; out valueHasToChange: boolean; out option: char; out min: longint; out max: longint)

Returns the callback configuration as set by SetAltitudeCallbackConfiguration.

The following constants are available for this function:

  • BRICKLET_BAROMETER_V2_THRESHOLD_OPTION_OFF = 'x'
  • BRICKLET_BAROMETER_V2_THRESHOLD_OPTION_OUTSIDE = 'o'
  • BRICKLET_BAROMETER_V2_THRESHOLD_OPTION_INSIDE = 'i'
  • BRICKLET_BAROMETER_V2_THRESHOLD_OPTION_SMALLER = '<'
  • BRICKLET_BAROMETER_V2_THRESHOLD_OPTION_GREATER = '>'
procedure TBrickletBarometerV2.SetTemperatureCallbackConfiguration(const period: longword; const valueHasToChange: boolean; const option: char; const min: longint; const max: longint)

The period in ms is the period with which the OnTemperature 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 OnTemperature 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:

  • BRICKLET_BAROMETER_V2_THRESHOLD_OPTION_OFF = 'x'
  • BRICKLET_BAROMETER_V2_THRESHOLD_OPTION_OUTSIDE = 'o'
  • BRICKLET_BAROMETER_V2_THRESHOLD_OPTION_INSIDE = 'i'
  • BRICKLET_BAROMETER_V2_THRESHOLD_OPTION_SMALLER = '<'
  • BRICKLET_BAROMETER_V2_THRESHOLD_OPTION_GREATER = '>'
procedure TBrickletBarometerV2.GetTemperatureCallbackConfiguration(out period: longword; out valueHasToChange: boolean; out option: char; out min: longint; out max: longint)

Returns the callback configuration as set by SetTemperatureCallbackConfiguration.

The following constants are available for this function:

  • BRICKLET_BAROMETER_V2_THRESHOLD_OPTION_OFF = 'x'
  • BRICKLET_BAROMETER_V2_THRESHOLD_OPTION_OUTSIDE = 'o'
  • BRICKLET_BAROMETER_V2_THRESHOLD_OPTION_INSIDE = 'i'
  • BRICKLET_BAROMETER_V2_THRESHOLD_OPTION_SMALLER = '<'
  • BRICKLET_BAROMETER_V2_THRESHOLD_OPTION_GREATER = '>'

Callbacks

Callbacks can be registered to receive time critical or recurring data from the device. The registration is done by assigning a procedure to an callback property of the device object:

procedure TExample.MyCallback(sender: TBrickletBarometerV2; const param: word);
begin
  WriteLn(param);
end;

barometerV2.OnExample := {$ifdef FPC}@{$endif}example.MyCallback;

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.

property TBrickletBarometerV2.OnAirPressure
procedure(sender: TBrickletBarometerV2; const airPressure: longint) of object;

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

The parameter is the same as GetAirPressure.

property TBrickletBarometerV2.OnAltitude
procedure(sender: TBrickletBarometerV2; const altitude: longint) of object;

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

The parameter is the same as GetAltitude.

property TBrickletBarometerV2.OnTemperature
procedure(sender: TBrickletBarometerV2; const temperature: longint) of object;

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

The parameter is the same as GetTemperature.

Constants

const BRICKLET_BAROMETER_V2_DEVICE_IDENTIFIER

This constant is used to identify a Barometer Bricklet 2.0.

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

const BRICKLET_BAROMETER_V2_DEVICE_DISPLAY_NAME

This constant represents the human readable name of a Barometer Bricklet 2.0.