Delphi/Lazarus - Humidity Bricklet

This is the description of the Delphi/Lazarus API bindings for the Humidity Bricklet. General information and technical specifications for the Humidity Bricklet 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, BrickletHumidity;

type
  TExample = class
  private
    ipcon: TIPConnection;
    h: TBrickletHumidity;
  public
    procedure Execute;
  end;

const
  HOST = 'localhost';
  PORT = 4223;
  UID = '9TU'; { Change to your UID }

var
  e: TExample;

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

  { Create device object }
  h := TBrickletHumidity.Create(UID, ipcon);

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

  { Get current humidity (unit is %RH/10) }
  humidity := h.GetHumidity;
  WriteLn(Format('Humidity: %f %%RH', [humidity/10.0]));

  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, BrickletHumidity;

type
  TExample = class
  private
    ipcon: TIPConnection;
    h: TBrickletHumidity;
  public
    procedure HumidityCB(sender: TBrickletHumidity; const humidity: word);
    procedure Execute;
  end;

const
  HOST = 'localhost';
  PORT = 4223;
  UID = '9TU'; { Change to your UID }

var
  e: TExample;

{ Callback function for humidity callback (parameter has unit %RH/10) }
procedure TExample.HumidityCB(sender: TBrickletHumidity; const humidity: word);
begin
  WriteLn(Format('Humidity: %f %%RH', [humidity/10.0]));
end;

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

  { Create device object }
  h := TBrickletHumidity.Create(UID, ipcon);

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

  { Set Period for humidity callback to 1s (1000ms)
    Note: The callback is only called every second if the
          humidity has changed since the last call! }
  h.SetHumidityCallbackPeriod(1000);

  { Register humidity callback to procedure HumidityCB }
  h.OnHumidity := {$ifdef FPC}@{$endif}HumidityCB;

  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, BrickletHumidity;

type
  TExample = class
  private
    ipcon: TIPConnection;
    h: TBrickletHumidity;
  public
    procedure ReachedCB(sender: TBrickletHumidity; const humidity: word);
    procedure Execute;
  end;

const
  HOST = 'localhost';
  PORT = 4223;
  UID = '9TU'; { Change to your UID }

var
  e: TExample;

{ Callback for humidity outside of 30 to 60 %RH }
procedure TExample.ReachedCB(sender: TBrickletHumidity; const humidity: word);
begin
  if (humidity < 30*10) then begin
    WriteLn(Format('Humidity too low: %f %%RH', [humidity/10.0]));
  end
  else begin
    WriteLn(Format('Humidity too high: %f %%RH', [humidity/10.0]));
  end;
  WriteLn('Recommended humiditiy for human comfort is 30 to 60 %RH.');
end;

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

  { Create device object }
  h := TBrickletHumidity.Create(UID, ipcon);

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

  { Get threshold callbacks with a debounce time of 10 seconds (10000ms) }
  h.SetDebouncePeriod(10000);

  { Register threshold reached callback to procedure ReachedCB }
  h.OnHumidityReached := {$ifdef FPC}@{$endif}ReachedCB;

  { Configure threshold for "outside of 30 to 60 %RH" (unit is %RH/10) }
  h.SetHumidityCallbackThreshold('o', 30*10, 60*10);

  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 TBrickletHumidity.Create(const uid: string; ipcon: TIPConnection)

Creates an object with the unique device ID uid:

humidity := TBrickletHumidity.Create('YOUR_DEVICE_UID', ipcon);

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

function TBrickletHumidity.GetHumidity: word

Returns the humidity of the sensor. The value has a range of 0 to 1000 and is given in %RH/10 (Relative Humidity), i.e. a value of 421 means that a humidity of 42.1 %RH is measured.

If you want to get the humidity periodically, it is recommended to use the callback OnHumidity and set the period with SetHumidityCallbackPeriod.

Advanced Functions

function TBrickletHumidity.GetAnalogValue: word

Returns the value as read by a 12-bit analog-to-digital converter. The value is between 0 and 4095.

Note

The value returned by GetHumidity is averaged over several samples to yield less noise, while GetAnalogValue gives back raw unfiltered analog values. The returned humidity value is calibrated for room temperatures, if you use the sensor in extreme cold or extreme warm environments, you might want to calculate the humidity from the analog value yourself. See the HIH 5030 datasheet.

If you want the analog value periodically, it is recommended to use the callback OnAnalogValue and set the period with SetAnalogValueCallbackPeriod.

function TBrickletHumidity.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 TBrickletHumidity.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 TBrickletHumidity.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 and callbacks it is always disabled.

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_HUMIDITY_FUNCTION_SET_HUMIDITY_CALLBACK_PERIOD = 3
  • BRICKLET_HUMIDITY_FUNCTION_SET_ANALOG_VALUE_CALLBACK_PERIOD = 5
  • BRICKLET_HUMIDITY_FUNCTION_SET_HUMIDITY_CALLBACK_THRESHOLD = 7
  • BRICKLET_HUMIDITY_FUNCTION_SET_ANALOG_VALUE_CALLBACK_THRESHOLD = 9
  • BRICKLET_HUMIDITY_FUNCTION_SET_DEBOUNCE_PERIOD = 11
procedure TBrickletHumidity.SetResponseExpectedAll(const responseExpected: boolean)

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

procedure TBrickletHumidity.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 TBrickletHumidity.SetHumidityCallbackPeriod(const period: longword)

Sets the period in ms with which the OnHumidity callback is triggered periodically. A value of 0 turns the callback off.

OnHumidity is only triggered if the humidity has changed since the last triggering.

The default value is 0.

function TBrickletHumidity.GetHumidityCallbackPeriod: longword

Returns the period as set by SetHumidityCallbackPeriod.

procedure TBrickletHumidity.SetAnalogValueCallbackPeriod(const period: longword)

Sets the period in ms with which the OnAnalogValue callback is triggered periodically. A value of 0 turns the callback off.

OnAnalogValue is only triggered if the analog value has changed since the last triggering.

The default value is 0.

function TBrickletHumidity.GetAnalogValueCallbackPeriod: longword

Returns the period as set by SetAnalogValueCallbackPeriod.

procedure TBrickletHumidity.SetHumidityCallbackThreshold(const option: char; const min: smallint; const max: smallint)

Sets the thresholds for the OnHumidityReached callback.

The following options are possible:

Option Description
'x' Callback is turned off
'o' Callback is triggered when the humidity is outside the min and max values
'i' Callback is triggered when the humidity is inside the min and max values
'<' Callback is triggered when the humidity is smaller than the min value (max is ignored)
'>' Callback is triggered when the humidity is greater than the min value (max is ignored)

The default value is ('x', 0, 0).

The following constants are available for this function:

  • BRICKLET_HUMIDITY_THRESHOLD_OPTION_OFF = 'x'
  • BRICKLET_HUMIDITY_THRESHOLD_OPTION_OUTSIDE = 'o'
  • BRICKLET_HUMIDITY_THRESHOLD_OPTION_INSIDE = 'i'
  • BRICKLET_HUMIDITY_THRESHOLD_OPTION_SMALLER = '<'
  • BRICKLET_HUMIDITY_THRESHOLD_OPTION_GREATER = '>'
procedure TBrickletHumidity.GetHumidityCallbackThreshold(out option: char; out min: smallint; out max: smallint)

Returns the threshold as set by SetHumidityCallbackThreshold.

The following constants are available for this function:

  • BRICKLET_HUMIDITY_THRESHOLD_OPTION_OFF = 'x'
  • BRICKLET_HUMIDITY_THRESHOLD_OPTION_OUTSIDE = 'o'
  • BRICKLET_HUMIDITY_THRESHOLD_OPTION_INSIDE = 'i'
  • BRICKLET_HUMIDITY_THRESHOLD_OPTION_SMALLER = '<'
  • BRICKLET_HUMIDITY_THRESHOLD_OPTION_GREATER = '>'
procedure TBrickletHumidity.SetAnalogValueCallbackThreshold(const option: char; const min: word; const max: word)

Sets the thresholds for the OnAnalogValueReached callback.

The following options are possible:

Option Description
'x' Callback is turned off
'o' Callback is triggered when the analog value is outside the min and max values
'i' Callback is triggered when the analog value is inside the min and max values
'<' Callback is triggered when the analog value is smaller than the min value (max is ignored)
'>' Callback is triggered when the analog value is greater than the min value (max is ignored)

The default value is ('x', 0, 0).

The following constants are available for this function:

  • BRICKLET_HUMIDITY_THRESHOLD_OPTION_OFF = 'x'
  • BRICKLET_HUMIDITY_THRESHOLD_OPTION_OUTSIDE = 'o'
  • BRICKLET_HUMIDITY_THRESHOLD_OPTION_INSIDE = 'i'
  • BRICKLET_HUMIDITY_THRESHOLD_OPTION_SMALLER = '<'
  • BRICKLET_HUMIDITY_THRESHOLD_OPTION_GREATER = '>'
procedure TBrickletHumidity.GetAnalogValueCallbackThreshold(out option: char; out min: word; out max: word)

Returns the threshold as set by SetAnalogValueCallbackThreshold.

The following constants are available for this function:

  • BRICKLET_HUMIDITY_THRESHOLD_OPTION_OFF = 'x'
  • BRICKLET_HUMIDITY_THRESHOLD_OPTION_OUTSIDE = 'o'
  • BRICKLET_HUMIDITY_THRESHOLD_OPTION_INSIDE = 'i'
  • BRICKLET_HUMIDITY_THRESHOLD_OPTION_SMALLER = '<'
  • BRICKLET_HUMIDITY_THRESHOLD_OPTION_GREATER = '>'
procedure TBrickletHumidity.SetDebouncePeriod(const debounce: longword)

Sets the period in ms with which the threshold callbacks

are triggered, if the thresholds

keep being reached.

The default value is 100.

function TBrickletHumidity.GetDebouncePeriod: longword

Returns the debounce period as set by SetDebouncePeriod.

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: TBrickletHumidity; const param: word);
begin
  WriteLn(param);
end;

humidity.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 TBrickletHumidity.OnHumidity
procedure(sender: TBrickletHumidity; const humidity: word) of object;

This callback is triggered periodically with the period that is set by SetHumidityCallbackPeriod. The parameter is the humidity of the sensor.

OnHumidity is only triggered if the humidity has changed since the last triggering.

property TBrickletHumidity.OnAnalogValue
procedure(sender: TBrickletHumidity; const value: word) of object;

This callback is triggered periodically with the period that is set by SetAnalogValueCallbackPeriod. The parameter is the analog value of the sensor.

OnAnalogValue is only triggered if the humidity has changed since the last triggering.

property TBrickletHumidity.OnHumidityReached
procedure(sender: TBrickletHumidity; const humidity: word) of object;

This callback is triggered when the threshold as set by SetHumidityCallbackThreshold is reached. The parameter is the humidity of the sensor.

If the threshold keeps being reached, the callback is triggered periodically with the period as set by SetDebouncePeriod.

property TBrickletHumidity.OnAnalogValueReached
procedure(sender: TBrickletHumidity; const value: word) of object;

This callback is triggered when the threshold as set by SetAnalogValueCallbackThreshold is reached. The parameter is the analog value of the sensor.

If the threshold keeps being reached, the callback is triggered periodically with the period as set by SetDebouncePeriod.

Constants

const BRICKLET_HUMIDITY_DEVICE_IDENTIFIER

This constant is used to identify a Humidity Bricklet.

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

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