Delphi/Lazarus - Motion Detector Bricklet

This is the description of the Delphi/Lazarus API bindings for the Motion Detector Bricklet. General information and technical specifications for the Motion Detector 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).

Callback

Download (ExampleCallback.pas)

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program ExampleCallback;

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

uses
  SysUtils, IPConnection, BrickletMotionDetector;

type
  TExample = class
  private
    ipcon: TIPConnection;
    md: TBrickletMotionDetector;
  public
    procedure MotionDetectedCB(sender: TBrickletMotionDetector);
    procedure DetectionCycleEndedCB(sender: TBrickletMotionDetector);
    procedure Execute;
  end;

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

var
  e: TExample;

{ Callback procedure for motion detected callback }
procedure TExample.MotionDetectedCB(sender: TBrickletMotionDetector);
begin
  WriteLn('Motion Detected');
end;

{ Callback procedure for detection cycle ended callback }
procedure TExample.DetectionCycleEndedCB(sender: TBrickletMotionDetector);
begin
  WriteLn('Detection Cycle Ended (next detection possible in ~3 seconds)');
end;

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

  { Create device object }
  md := TBrickletMotionDetector.Create(UID, ipcon);

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

  { Register motion detected callback to procedure MotionDetectedCB }
  md.OnMotionDetected := {$ifdef FPC}@{$endif}MotionDetectedCB;

  { Register detection cycle ended callback to procedure DetectionCycleEndedCB }
  md.OnDetectionCycleEnded := {$ifdef FPC}@{$endif}DetectionCycleEndedCB;

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

Creates an object with the unique device ID uid:

motionDetector := TBrickletMotionDetector.Create('YOUR_DEVICE_UID', ipcon);

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

function TBrickletMotionDetector.GetMotionDetected: byte

Returns 1 if a motion was detected. How long this returns 1 after a motion was detected can be adjusted with one of the small potentiometers on the Motion Detector Bricklet, see here.

There is also a blue LED on the Bricklet that is on as long as the Bricklet is in the "motion detected" state.

The following constants are available for this function:

  • BRICKLET_MOTION_DETECTOR_MOTION_NOT_DETECTED = 0
  • BRICKLET_MOTION_DETECTOR_MOTION_DETECTED = 1

Advanced Functions

procedure TBrickletMotionDetector.SetStatusLEDConfig(const config: byte)

Sets the status led configuration.

By default the status LED turns on if a motion is detected and off is no motion is detected.

You can also turn the LED permanently on/off.

The following constants are available for this function:

  • BRICKLET_MOTION_DETECTOR_STATUS_LED_CONFIG_OFF = 0
  • BRICKLET_MOTION_DETECTOR_STATUS_LED_CONFIG_ON = 1
  • BRICKLET_MOTION_DETECTOR_STATUS_LED_CONFIG_SHOW_STATUS = 2

New in version 2.0.1 (Plugin).

function TBrickletMotionDetector.GetStatusLEDConfig: byte

Returns the configuration as set by SetStatusLEDConfig.

The following constants are available for this function:

  • BRICKLET_MOTION_DETECTOR_STATUS_LED_CONFIG_OFF = 0
  • BRICKLET_MOTION_DETECTOR_STATUS_LED_CONFIG_ON = 1
  • BRICKLET_MOTION_DETECTOR_STATUS_LED_CONFIG_SHOW_STATUS = 2

New in version 2.0.1 (Plugin).

function TBrickletMotionDetector.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 TBrickletMotionDetector.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 TBrickletMotionDetector.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_MOTION_DETECTOR_FUNCTION_SET_STATUS_LED_CONFIG = 4
procedure TBrickletMotionDetector.SetResponseExpectedAll(const responseExpected: boolean)

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

procedure TBrickletMotionDetector.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

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

motionDetector.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 TBrickletMotionDetector.OnMotionDetected
procedure(sender: TBrickletMotionDetector) of object;

This callback is called after a motion was detected.

property TBrickletMotionDetector.OnDetectionCycleEnded
procedure(sender: TBrickletMotionDetector) of object;

This callback is called when the detection cycle ended. When this callback is called, a new motion can be detected again after approximately 2 seconds.

Constants

const BRICKLET_MOTION_DETECTOR_DEVICE_IDENTIFIER

This constant is used to identify a Motion Detector 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.

const BRICKLET_MOTION_DETECTOR_DEVICE_DISPLAY_NAME

This constant represents the human readable name of a Motion Detector Bricklet.