Software / API Bindings / Perl / API Reference and Examples / Bricklets (Discontinued) / Ambient Light Bricklet

Perl - Ambient Light Bricklet¶

This is the description of the Perl API bindings for the Ambient Light Bricklet. General information and technical specifications for the Ambient Light 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).

Simple¶

Download (example_simple.pl)

#!/usr/bin/perl

use strict;
use Tinkerforge::IPConnection;
use Tinkerforge::BrickletAmbientLight;

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

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

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

# Get current illuminance
my $illuminance = $al->get_illuminance();
print "Illuminance: " . $illuminance/10.0 . " lx\n";

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

Callback¶

Download (example_callback.pl)

#!/usr/bin/perl

use strict;
use Tinkerforge::IPConnection;
use Tinkerforge::BrickletAmbientLight;

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

# Callback subroutine for illuminance callback
sub cb_illuminance
{
    my ($illuminance) = @_;

    print "Illuminance: " . $illuminance/10.0 . " lx\n";
}

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

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

# Register illuminance callback to subroutine cb_illuminance
$al->register_callback($al->CALLBACK_ILLUMINANCE, 'cb_illuminance');

# Set period for illuminance callback to 1s (1000ms)
# Note: The illuminance callback is only called every second
#       if the illuminance has changed since the last call!
$al->set_illuminance_callback_period(1000);

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

Threshold¶

Download (example_threshold.pl)

#!/usr/bin/perl

use strict;
use Tinkerforge::IPConnection;
use Tinkerforge::BrickletAmbientLight;

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

# Callback subroutine for illuminance reached callback
sub cb_illuminance_reached
{
    my ($illuminance) = @_;

    print "Illuminance: " . $illuminance/10.0 . " lx\n";
    print "Too bright, close the curtains!\n";
}

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

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

# Get threshold callbacks with a debounce time of 10 seconds (10000ms)
$al->set_debounce_period(10000);

# Register illuminance reached callback to subroutine cb_illuminance_reached
$al->register_callback($al->CALLBACK_ILLUMINANCE_REACHED, 'cb_illuminance_reached');

# Configure threshold for illuminance "greater than 200 lx"
$al->set_illuminance_callback_threshold('>', 200*10, 0);

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¶

BrickletAmbientLight->new($uid, $ipcon)¶

Parameters:	$uid – Type: string $ipcon – Type: IPConnection
Returns:	$ambient_light – Type: BrickletAmbientLight

Creates an object with the unique device ID $uid:

$ambient_light = BrickletAmbientLight->new("YOUR_DEVICE_UID", $ipcon);

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

BrickletAmbientLight->get_illuminance()¶

Returns:	$illuminance – Type: int, Unit: 1/10 lx, Range: [0 to 9000]

Returns the illuminance of the ambient light sensor.

If you want to get the illuminance periodically, it is recommended to use the CALLBACK_ILLUMINANCE callback and set the period with set_illuminance_callback_period().

Advanced Functions¶

BrickletAmbientLight->get_analog_value()¶

Returns:	$value – Type: int, Range: [0 to 2¹² - 1]

Returns the value as read by a 12-bit analog-to-digital converter.

Note

The value returned by get_illuminance() is averaged over several samples to yield less noise, while get_analog_value() gives back raw unfiltered analog values. The only reason to use get_analog_value() is, if you need the full resolution of the analog-to-digital converter.

Also, the analog-to-digital converter covers three different ranges that are set dynamically depending on the light intensity. It is impossible to distinguish between these ranges with the analog value.

If you want the analog value periodically, it is recommended to use the CALLBACK_ANALOG_VALUE callback and set the period with set_analog_value_callback_period().

BrickletAmbientLight->get_identity()¶

Return Array:

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]

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¶

BrickletAmbientLight->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.

BrickletAmbientLight->set_illuminance_callback_period($period)¶

Parameters:	$period – Type: int, Unit: 1 ms, Range: [0 to 2³² - 1], Default: 0
Returns:	undef

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

The CALLBACK_ILLUMINANCE callback is only triggered if the illuminance has changed since the last triggering.

BrickletAmbientLight->get_illuminance_callback_period()¶

Returns:	$period – Type: int, Unit: 1 ms, Range: [0 to 2³² - 1], Default: 0

Returns the period as set by set_illuminance_callback_period().

BrickletAmbientLight->set_analog_value_callback_period($period)¶

Parameters:	$period – Type: int, Unit: 1 ms, Range: [0 to 2³² - 1], Default: 0
Returns:	undef

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

The CALLBACK_ANALOG_VALUE callback is only triggered if the analog value has changed since the last triggering.

BrickletAmbientLight->get_analog_value_callback_period()¶

Returns:	$period – Type: int, Unit: 1 ms, Range: [0 to 2³² - 1], Default: 0

Returns the period as set by set_analog_value_callback_period().

BrickletAmbientLight->set_illuminance_callback_threshold($option, $min, $max)¶

Parameters:	$option – Type: char, Range: See constants, Default: 'x' $min – Type: int, Unit: 1/10 lx, Range: [0 to 2¹⁶ - 1], Default: 0 $max – Type: int, Unit: 1/10 lx, Range: [0 to 2¹⁶ - 1], Default: 0
Returns:	undef

Sets the thresholds for the CALLBACK_ILLUMINANCE_REACHED callback.

The following options are possible:

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

The following constants are available for this function:

For $option:

BrickletAmbientLight->THRESHOLD_OPTION_OFF = 'x'
BrickletAmbientLight->THRESHOLD_OPTION_OUTSIDE = 'o'
BrickletAmbientLight->THRESHOLD_OPTION_INSIDE = 'i'
BrickletAmbientLight->THRESHOLD_OPTION_SMALLER = '<'
BrickletAmbientLight->THRESHOLD_OPTION_GREATER = '>'

BrickletAmbientLight->get_illuminance_callback_threshold()¶

Return Array:	0: $option – Type: char, Range: See constants, Default: 'x' 1: $min – Type: int, Unit: 1/10 lx, Range: [0 to 2¹⁶ - 1], Default: 0 2: $max – Type: int, Unit: 1/10 lx, Range: [0 to 2¹⁶ - 1], Default: 0

Returns the threshold as set by set_illuminance_callback_threshold().

The following constants are available for this function:

For $option:

BrickletAmbientLight->THRESHOLD_OPTION_OFF = 'x'
BrickletAmbientLight->THRESHOLD_OPTION_OUTSIDE = 'o'
BrickletAmbientLight->THRESHOLD_OPTION_INSIDE = 'i'
BrickletAmbientLight->THRESHOLD_OPTION_SMALLER = '<'
BrickletAmbientLight->THRESHOLD_OPTION_GREATER = '>'

BrickletAmbientLight->set_analog_value_callback_threshold($option, $min, $max)¶

Parameters:	$option – Type: char, Range: See constants, Default: 'x' $min – Type: int, Range: [0 to 2¹⁶ - 1], Default: 0 $max – Type: int, Range: [0 to 2¹⁶ - 1], Default: 0
Returns:	undef

Sets the thresholds for the CALLBACK_ANALOG_VALUE_REACHED 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 following constants are available for this function:

For $option:

BrickletAmbientLight->THRESHOLD_OPTION_OFF = 'x'
BrickletAmbientLight->THRESHOLD_OPTION_OUTSIDE = 'o'
BrickletAmbientLight->THRESHOLD_OPTION_INSIDE = 'i'
BrickletAmbientLight->THRESHOLD_OPTION_SMALLER = '<'
BrickletAmbientLight->THRESHOLD_OPTION_GREATER = '>'

BrickletAmbientLight->get_analog_value_callback_threshold()¶

Return Array:	0: $option – Type: char, Range: See constants, Default: 'x' 1: $min – Type: int, Range: [0 to 2¹⁶ - 1], Default: 0 2: $max – Type: int, Range: [0 to 2¹⁶ - 1], Default: 0

Returns the threshold as set by set_analog_value_callback_threshold().

The following constants are available for this function:

For $option:

BrickletAmbientLight->THRESHOLD_OPTION_OFF = 'x'
BrickletAmbientLight->THRESHOLD_OPTION_OUTSIDE = 'o'
BrickletAmbientLight->THRESHOLD_OPTION_INSIDE = 'i'
BrickletAmbientLight->THRESHOLD_OPTION_SMALLER = '<'
BrickletAmbientLight->THRESHOLD_OPTION_GREATER = '>'

BrickletAmbientLight->set_debounce_period($debounce)¶

Parameters:	$debounce – Type: int, Unit: 1 ms, Range: [0 to 2³² - 1], Default: 100
Returns:	undef

Sets the period with which the threshold callbacks

CALLBACK_ILLUMINANCE_REACHED,
CALLBACK_ANALOG_VALUE_REACHED

are triggered, if the thresholds

set_illuminance_callback_threshold(),
set_analog_value_callback_threshold()

keep being reached.

BrickletAmbientLight->get_debounce_period()¶

Returns:	$debounce – Type: int, Unit: 1 ms, Range: [0 to 2³² - 1], Default: 100

Returns the debounce period as set by set_debounce_period().

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]";
}

$ambient_light->register_callback(BrickletAmbientLight->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.

BrickletAmbientLight->CALLBACK_ILLUMINANCE¶

Callback Parameters:	$illuminance – Type: int, Unit: 1/10 lx, Range: [0 to 9000]

This callback is triggered periodically with the period that is set by set_illuminance_callback_period(). The parameter is the illuminance of the ambient light sensor.

The CALLBACK_ILLUMINANCE callback is only triggered if the illuminance has changed since the last triggering.

BrickletAmbientLight->CALLBACK_ANALOG_VALUE¶

Callback Parameters:	$value – Type: int, Range: [0 to 2¹² - 1]

This callback is triggered periodically with the period that is set by set_analog_value_callback_period(). The parameter is the analog value of the ambient light sensor.

The CALLBACK_ANALOG_VALUE callback is only triggered if the analog value has changed since the last triggering.

BrickletAmbientLight->CALLBACK_ILLUMINANCE_REACHED¶

Callback Parameters:	$illuminance – Type: int, Unit: 1/10 lx, Range: [0 to 9000]

This callback is triggered when the threshold as set by set_illuminance_callback_threshold() is reached. The parameter is the illuminance of the ambient light sensor.

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

BrickletAmbientLight->CALLBACK_ANALOG_VALUE_REACHED¶

Callback Parameters:	$value – Type: int, Range: [0 to 2¹² - 1]

This callback is triggered when the threshold as set by set_analog_value_callback_threshold() is reached. The parameter is the analog value of the ambient light sensor.

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

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.

BrickletAmbientLight->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.

BrickletAmbientLight->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:

BrickletAmbientLight->FUNCTION_SET_ILLUMINANCE_CALLBACK_PERIOD = 3
BrickletAmbientLight->FUNCTION_SET_ANALOG_VALUE_CALLBACK_PERIOD = 5
BrickletAmbientLight->FUNCTION_SET_ILLUMINANCE_CALLBACK_THRESHOLD = 7
BrickletAmbientLight->FUNCTION_SET_ANALOG_VALUE_CALLBACK_THRESHOLD = 9
BrickletAmbientLight->FUNCTION_SET_DEBOUNCE_PERIOD = 11

BrickletAmbientLight->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.

The following constants are available for this function:

For $function_id:

BrickletAmbientLight->FUNCTION_SET_ILLUMINANCE_CALLBACK_PERIOD = 3
BrickletAmbientLight->FUNCTION_SET_ANALOG_VALUE_CALLBACK_PERIOD = 5
BrickletAmbientLight->FUNCTION_SET_ILLUMINANCE_CALLBACK_THRESHOLD = 7
BrickletAmbientLight->FUNCTION_SET_ANALOG_VALUE_CALLBACK_THRESHOLD = 9
BrickletAmbientLight->FUNCTION_SET_DEBOUNCE_PERIOD = 11

BrickletAmbientLight->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¶

BrickletAmbientLight->DEVICE_IDENTIFIER¶

This constant is used to identify a Ambient Light 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.

BrickletAmbientLight->DEVICE_DISPLAY_NAME¶: This constant represents the human readable name of a Ambient Light Bricklet.