This is the description of the Perl API bindings for the LED Strip Bricklet. General information and technical specifications for the LED Strip Bricklet are summarized in its hardware description.
An installation guide for the Perl API bindings is part of their general description.
The example code below is Public Domain (CC0 1.0).
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 | #!/usr/bin/perl
use Tinkerforge::IPConnection;
use Tinkerforge::BrickletLEDStrip;
use constant HOST => 'localhost';
use constant PORT => 4223;
use constant UID => 'oud'; # Change to your UID
my $ipcon = Tinkerforge::IPConnection->new(); # Create IP connection
my $led_strip = Tinkerforge::BrickletLEDStrip->new(&UID, $ipcon); # Create device object
$ipcon->connect(&HOST, &PORT); # Connect to brickd
# Don't use device before ipcon is connected
# Set first 10 LEDs to green
my $r = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0];
my $g = [255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 0, 0, 0, 0, 0, 0];
my $b = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0];
$led_strip->set_rgb_values(0, 10, $r, $g, $b);
print "Press any key to exit...\n";
<STDIN>;
$ipcon->disconnect();
|
Download (example_callback.pl)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 | #!/usr/bin/perl
use Tinkerforge::IPConnection;
use Tinkerforge::BrickletLEDStrip;
use constant HOST => 'localhost';
use constant PORT => 4223;
use constant UID => 'jEE'; # Change to your UID
use constant NUM_LEDS => 16;
our $r = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0];
our $g = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0];
our $b = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0];
our $r_index = 0;
my $ipcon = Tinkerforge::IPConnection->new(); # Create IP connection
our $led_strip = Tinkerforge::BrickletLEDStrip->new(&UID, $ipcon); # Create device object
# Frame rendered callback, is called when a new frame was rendered
# We increase the index of one blue LED with every frame
sub cb_frame_rendered
{
my ($length) = @_;
@{$b}[$r_index] = 0;
if ($r_index == NUM_LEDS-1)
{
$r_index = 0;
}
else
{
$r_index += 1;
}
@{$b}[$r_index] = 255;
# Set new data for next render cycle
$led_strip->set_rgb_values(0, NUM_LEDS, $r, $g, $b);
}
$ipcon->connect(&HOST, &PORT); # Connect to brickd
# Don't use device before ipcon is connected
# Set frame duration to 50ms (20 frames per second)
$led_strip->set_frame_duration(50);
# Register frame rendered callback to function cb_frame_rendered
$led_strip->register_callback($led_strip->CALLBACK_FRAME_RENDERED, 'cb_frame_rendered');
# Set initial rgb values to get started
$led_strip->set_rgb_values(0, NUM_LEDS, $r, $g, $b);
print "Press any key to exit...\n";
<STDIN>;
$ipcon->disconnect();
|
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:
All methods listed below are thread-safe.
Parameters: |
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Return type: | BrickletLEDStrip |
Creates an object with the unique device ID $uid:
$led_strip = BrickletLEDStrip->new("YOUR_DEVICE_UID", $ipcon);
This object can then be used after the IP Connection is connected (see examples above).
Parameters: |
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Return type: | undef |
Sets the rgb values for the LEDs with the given length starting from index.
The maximum length is 16, the index goes from 0 to 319 and the rgb values have 8 bits each.
Example: If you set
the LED with index 5 will be red, 6 will be green and 7 will be blue.
Note
Depending on the LED circuitry colors can be permuted.
The colors will be transfered to actual LEDs when the next frame duration ends, see set_frame_duration().
Generic approach:
This approach ensures that you can change the LED colors with a fixed frame rate.
The actual number of controllable LEDs depends on the number of free Bricklet ports. See here for more information. A call of set_rgb_values() with index + length above the bounds is ignored completely.
Parameters: |
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Return type: | [[int, int, int, int, int, int, int, int, int, int, int, int, int, int, int, int], [int, int, int, int, int, int, int, int, int, int, int, int, int, int, int, int], [int, int, int, int, int, int, int, int, int, int, int, int, int, int, int, int]] |
Returns the rgb with the given length starting from the given index.
The values are the last values that were set by set_rgb_values().
The returned array contains the elements r, g and b.
Parameters: | $duration -- int |
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Return type: | undef |
Sets the frame duration in ms.
Example: If you want to achieve 20 frames per second, you should set the frame duration to 50ms (50ms * 20 = 1 second).
For an explanation of the general approach see set_rgb_values().
Default value: 100ms (10 frames per second).
Return type: | int |
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Returns the frame duration as set by set_frame_duration().
Return type: | int |
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Returns the current supply voltage of the LEDs. The voltage is given in mV.
Parameters: | $frequency -- int |
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Return type: | undef |
Sets the frequency of the clock in Hz. The range is 10000Hz (10kHz) up to 2000000Hz (2MHz).
The Bricklet will choose the nearest achievable frequency, which may be off by a few Hz. You can get the exact frequency that is used by calling get_clock_frequency().
If you have problems with flickering LEDs, they may be bits flipping. You can fix this by either making the connection between the LEDs and the Bricklet shorter or by reducing the frequency.
With a decreasing frequency your maximum frames per second will decrease too.
The default value is 1.66MHz.
Note
The frequency in firmware version 2.0.0 is fixed at 2MHz.
New in version 2.0.1 (Plugin).
Return type: | int |
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Returns the currently used clock frequency as set by set_clock_frequency().
New in version 2.0.1 (Plugin).
Parameters: | $chip -- int |
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Return type: | undef |
Sets the type of the led driver chip. We currently support the chips
The WS2812 is sometimes also called "NeoPixel", a name coined by Adafruit.
The default value is WS2801 (chip = 2801).
The following constants are available for this function:
New in version 2.0.2 (Plugin).
Return type: | int |
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Returns the currently used chip type as set by set_chip_type().
The following constants are available for this function:
New in version 2.0.2 (Plugin).
Return type: | [int, int, int] |
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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.
Parameters: | $function_id -- int |
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Return 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 send and errors are silently ignored, because they cannot be detected.
See set_response_expected() for the list of function ID constants available for this function.
Parameters: |
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Return type: | 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 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:
Parameters: | $response_expected -- bool |
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Return type: | undef |
Changes the response expected flag for all setter and callback configuration functions of this device at once.
Return type: | [string, string, char, [int, int, int], [int, int, int], int] |
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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.
The returned array contains the elements uid, connected_uid, position, hardware_version, firmware_version and device_identifier.
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]";
}
$led_strip->register_callback(BrickletLEDStrip->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.
Parameters: | $length -- int |
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This callback is triggered directly after a new frame is rendered.
You should send the data for the next frame directly after this callback was triggered.
For an explanation of the general approach see set_rgb_values().
This constant is used to identify a LED Strip Bricklet.
The get_identity() function and the CALLBACK_ENUMERATE callback of the IP Connection have a device_identifier parameter to specify the Brick's or Bricklet's type.