Perl - Motion Detector Bricklet

This is the description of the Perl 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 Perl API bindings is part of their general description.

Examples

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

Callback

Download (example_callback.pl)

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#!/usr/bin/perl

use strict;
use Tinkerforge::IPConnection;
use Tinkerforge::BrickletMotionDetector;

use constant HOST => 'localhost';
use constant PORT => 4223;
use constant UID => 'XYZ'; # Change XYZ to the UID of your Motion Detector Bricklet

# Callback subroutine for motion detected callback
sub cb_motion_detected
{
    print "Motion Detected\n";
}

# Callback subroutine for detection cycle ended callback
sub cb_detection_cycle_ended
{
    print "Detection Cycle Ended (next detection possible in ~3 seconds)\n";
}

my $ipcon = Tinkerforge::IPConnection->new(); # Create IP connection
my $md = Tinkerforge::BrickletMotionDetector->new(&UID, $ipcon); # Create device object

$ipcon->connect(&HOST, &PORT); # Connect to brickd
# Don't use device before ipcon is connected

# Register motion detected callback to subroutine cb_motion_detected
$md->register_callback($md->CALLBACK_MOTION_DETECTED, 'cb_motion_detected');

# Register detection cycle ended callback to subroutine cb_detection_cycle_ended
$md->register_callback($md->CALLBACK_DETECTION_CYCLE_ENDED, 'cb_detection_cycle_ended');

print "Press key to exit\n";
<STDIN>;
$ipcon->disconnect();

API

Generally, every subroutine of the Perl bindings can report an error as Tinkerforge::Error object via croak(). The object has a get_code() and a get_message() subroutine. There are different error code:

  • Error->ALREADY_CONNECTED = 11
  • Error->NOT_CONNECTED = 12
  • Error->CONNECT_FAILED = 13
  • Error->INVALID_FUNCTION_ID = 21
  • Error->TIMEOUT = 31
  • Error->INVALID_PARAMETER = 41
  • Error->FUNCTION_NOT_SUPPORTED = 42
  • Error->UNKNOWN_ERROR = 43
  • Error->STREAM_OUT_OF_SYNC = 51
  • Error->INVALID_UID = 61
  • Error->NON_ASCII_CHAR_IN_SECRET = 71
  • Error->WRONG_DEVICE_TYPE = 81
  • Error->DEVICE_REPLACED = 82
  • Error->WRONG_RESPONSE_LENGTH = 83

All functions listed below are thread-safe.

Basic Functions

BrickletMotionDetector->new($uid, $ipcon)
Parameters:
  • $uid – Type: string
  • $ipcon – Type: IPConnection
Returns:
  • $motion_detector – Type: BrickletMotionDetector

Creates an object with the unique device ID $uid:

$motion_detector = BrickletMotionDetector->new("YOUR_DEVICE_UID", $ipcon);

This object can then be used after the IP Connection is connected.

BrickletMotionDetector->get_motion_detected()
Returns:
  • $motion – Type: int, Range: See constants

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:

For $motion:

  • BrickletMotionDetector->MOTION_NOT_DETECTED = 0
  • BrickletMotionDetector->MOTION_DETECTED = 1

Advanced Functions

BrickletMotionDetector->set_status_led_config($config)
Parameters:
  • $config – Type: int, Range: See constants, Default: 2
Returns:
  • undef

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:

For $config:

  • BrickletMotionDetector->STATUS_LED_CONFIG_OFF = 0
  • BrickletMotionDetector->STATUS_LED_CONFIG_ON = 1
  • BrickletMotionDetector->STATUS_LED_CONFIG_SHOW_STATUS = 2

New in version 2.0.1 (Plugin).

BrickletMotionDetector->get_status_led_config()
Returns:
  • $config – Type: int, Range: See constants, Default: 2

Returns the configuration as set by set_status_led_config().

The following constants are available for this function:

For $config:

  • BrickletMotionDetector->STATUS_LED_CONFIG_OFF = 0
  • BrickletMotionDetector->STATUS_LED_CONFIG_ON = 1
  • BrickletMotionDetector->STATUS_LED_CONFIG_SHOW_STATUS = 2

New in version 2.0.1 (Plugin).

BrickletMotionDetector->get_identity()
Return Array:
  • 0: $uid – Type: string, Length: up to 8
  • 1: $connected_uid – Type: string, Length: up to 8
  • 2: $position – Type: char, Range: ['a' to 'h', 'z']
  • 3: \@hardware_version – Type: [int, ...], 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]
  • 4: \@firmware_version – Type: [int, ...], 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]
  • 5: $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. There is also a constant for the device identifier of this Bricklet.

Callback Configuration Functions

BrickletMotionDetector->register_callback($callback_id, $function)
Parameters:
  • $callback_id – Type: int
  • $function – Type: string
Returns:
  • undef

Registers the given $function name with the given $callback_id.

The available callback IDs with corresponding function signatures are listed below.

Callbacks

Callbacks can be registered to receive time critical or recurring data from the device. The registration is done with the register_callback() function of the device object. The first parameter is the callback ID and the second parameter the callback function name:

sub my_callback
{
    print "@_[0]";
}

$motion_detector->register_callback(BrickletMotionDetector->CALLBACK_EXAMPLE, 'my_callback')

The callback function will be called from an internal thread of the IP Connection. In contrast to many other programming languages, variables are not automatically shared between threads in Perl. If you want to share a global variable between a callback function and the rest for your program it has to be marked as :shared. See the documentation of the threads::shared Perl module for more details.

The available constants with inherent number and 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.

BrickletMotionDetector->CALLBACK_MOTION_DETECTED
Callback Parameters:
  • no parameters

This callback is called after a motion was detected.

BrickletMotionDetector->CALLBACK_DETECTION_CYCLE_ENDED
Callback Parameters:
  • no parameters

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.

Virtual Functions

Virtual functions don't communicate with the device itself, but operate only on the API bindings device object. They can be called without the corresponding IP Connection object being connected.

BrickletMotionDetector->get_api_version()
Return Array:
  • 0: \@api_version – Type: [int, ...], 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]

Returns the version of the API definition 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.

BrickletMotionDetector->get_response_expected($function_id)
Parameters:
  • $function_id – Type: int, Range: See constants
Returns:
  • $response_expected – Type: bool

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 set_response_expected(). 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 sent and errors are silently ignored, because they cannot be detected.

The following constants are available for this function:

For $function_id:

  • BrickletMotionDetector->FUNCTION_SET_STATUS_LED_CONFIG = 4
BrickletMotionDetector->set_response_expected($function_id, $response_expected)
Parameters:
  • $function_id – Type: int, Range: See constants
  • $response_expected – Type: bool
Returns:
  • undef

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 sent and errors are silently ignored, because they cannot be detected.

The following constants are available for this function:

For $function_id:

  • BrickletMotionDetector->FUNCTION_SET_STATUS_LED_CONFIG = 4
BrickletMotionDetector->set_response_expected_all($response_expected)
Parameters:
  • $response_expected – Type: bool
Returns:
  • undef

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

Constants

BrickletMotionDetector->DEVICE_IDENTIFIER

This constant is used to identify a Motion Detector Bricklet.

The get_identity() function and the IPConnection->CALLBACK_ENUMERATE callback of the IP Connection have a device_identifier parameter to specify the Brick's or Bricklet's type.

BrickletMotionDetector->DEVICE_DISPLAY_NAME

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