This is the description of the Python 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 Python 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 | #!/usr/bin/env python
# -*- coding: utf-8 -*-
HOST = "localhost"
PORT = 4223
UID = "XYZ" # Change XYZ to the UID of your LED Strip Bricklet
from tinkerforge.ip_connection import IPConnection
from tinkerforge.bricklet_led_strip import BrickletLEDStrip
if __name__ == "__main__":
ipcon = IPConnection() # Create IP connection
ls = BrickletLEDStrip(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
ls.set_rgb_values(0, 10, [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
[255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 0, 0, 0, 0, 0, 0],
[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0])
input("Press key to exit\n") # Use raw_input() in Python 2
ipcon.disconnect()
|
Download (example_callback.py)
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 | #!/usr/bin/env python
# -*- coding: utf-8 -*-
HOST = "localhost"
PORT = 4223
UID = "XYZ" # Change XYZ to the UID of your LED Strip Bricklet
NUM_LEDS = 16
r = [0]*NUM_LEDS
g = [0]*NUM_LEDS
b = [0]*NUM_LEDS
r_index = 0
from tinkerforge.ip_connection import IPConnection
from tinkerforge.bricklet_led_strip import BrickletLEDStrip
# Use frame rendered callback to move the active LED every frame
def cb_frame_rendered(length, ls):
global r_index
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
ls.set_rgb_values(0, NUM_LEDS, r, g, b)
if __name__ == "__main__":
ipcon = IPConnection() # Create IP connection
ls = BrickletLEDStrip(UID, ipcon) # Create device object
ipcon.connect(HOST, PORT) # Connect to brickd
# Don't use device before ipcon is connected
# Set frame duration to 50ms (20 frames per second)
ls.set_frame_duration(50)
# Register frame rendered callback to function cb_frame_rendered
ls.register_callback(ls.CALLBACK_FRAME_RENDERED,
lambda x: cb_frame_rendered(x, ls))
# Set initial rgb values to get started
ls.set_rgb_values(0, NUM_LEDS, r, g, b)
input("Press key to exit\n") # Use raw_input() in Python 2
ipcon.disconnect()
|
Generally, every function of the Python bindings can throw an
tinkerforge.ip_connection.Error
exception that has a value
and a
description
property. value
can have different values:
All functions listed below are thread-safe.
BrickletLEDStrip
(uid, ipcon)¶Parameters: |
|
---|---|
Returns: |
|
Creates an object with the unique device ID uid
:
led_strip = BrickletLEDStrip("YOUR_DEVICE_UID", ipcon)
This object can then be used after the IP Connection is connected.
BrickletLEDStrip.
set_rgb_values
(index, length, r, g, b)¶Parameters: |
|
---|---|
Returns: |
|
Sets length RGB values for the LEDs starting from index.
To make the colors show correctly you need to configure the chip type
(set_chip_type()
) and a 3-channel channel mapping (set_channel_mapping()
)
according to the connected LEDs.
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:
CALLBACK_FRAME_RENDERED
callback.CALLBACK_FRAME_RENDERED
callback.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.
BrickletLEDStrip.
get_rgb_values
(index, length)¶Parameters: |
|
---|---|
Return Object: |
|
Returns length R, G and B values starting from the given LED index.
The values are the last values that were set by set_rgb_values()
.
BrickletLEDStrip.
set_frame_duration
(duration)¶Parameters: |
|
---|---|
Returns: |
|
Sets the frame duration.
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()
.
BrickletLEDStrip.
get_frame_duration
()¶Returns: |
|
---|
Returns the frame duration as set by set_frame_duration()
.
BrickletLEDStrip.
get_supply_voltage
()¶Returns: |
|
---|
Returns the current supply voltage of the LEDs.
BrickletLEDStrip.
set_clock_frequency
(frequency)¶Parameters: |
|
---|---|
Returns: |
|
Sets the frequency of the clock.
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.
Note
The frequency in firmware version 2.0.0 is fixed at 2MHz.
New in version 2.0.1 (Plugin).
BrickletLEDStrip.
get_clock_frequency
()¶Returns: |
|
---|
Returns the currently used clock frequency as set by set_clock_frequency()
.
New in version 2.0.1 (Plugin).
BrickletLEDStrip.
set_chip_type
(chip)¶Parameters: |
|
---|---|
Returns: |
|
Sets the type of the LED driver chip. We currently support the chips
The following constants are available for this function:
For chip:
New in version 2.0.2 (Plugin).
BrickletLEDStrip.
get_chip_type
()¶Returns: |
|
---|
Returns the currently used chip type as set by set_chip_type()
.
The following constants are available for this function:
For chip:
New in version 2.0.2 (Plugin).
BrickletLEDStrip.
set_rgbw_values
(index, length, r, g, b, w)¶Parameters: |
|
---|---|
Returns: |
|
Sets length RGBW values for the LEDs starting from index.
To make the colors show correctly you need to configure the chip type
(set_chip_type()
) and a 4-channel channel mapping (set_channel_mapping()
)
according to the connected LEDs.
The maximum length is 12, the index goes from 0 to 239 and the rgbw values have 8 bits each.
Example: If you set
the LED with index 5 will be red, 6 will be green, 7 will be blue and 8 will be white.
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:
CALLBACK_FRAME_RENDERED
callback.CALLBACK_FRAME_RENDERED
callback.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_rgbw_values()
with index + length above the
bounds is ignored completely.
The LPD8806 LED driver chips have 7-bit channels for RGB. Internally the LED Strip Bricklets divides the 8-bit values set using this function by 2 to make them 7-bit. Therefore, you can just use the normal value range (0-255) for LPD8806 LEDs.
The brightness channel of the APA102 LED driver chips has 5-bit. Internally the LED Strip Bricklets divides the 8-bit values set using this function by 8 to make them 5-bit. Therefore, you can just use the normal value range (0-255) for the brightness channel of APA102 LEDs.
New in version 2.0.6 (Plugin).
BrickletLEDStrip.
get_rgbw_values
(index, length)¶Parameters: |
|
---|---|
Return Object: |
|
Returns length RGBW values starting from the given index.
The values are the last values that were set by set_rgbw_values()
.
New in version 2.0.6 (Plugin).
BrickletLEDStrip.
set_channel_mapping
(mapping)¶Parameters: |
|
---|---|
Returns: |
|
Sets the channel mapping for the connected LEDs.
set_rgb_values()
and set_rgbw_values()
take the data in RGB(W) order.
But the connected LED driver chips might have their 3 or 4 channels in a
different order. For example, the WS2801 chips typically use BGR order, the
WS2812 chips typically use GRB order and the APA102 chips typically use WBGR
order.
The APA102 chips are special. They have three 8-bit channels for RGB and an additional 5-bit channel for the overall brightness of the RGB LED making them 4-channel chips. Internally the brightness channel is the first channel, therefore one of the Wxyz channel mappings should be used. Then the W channel controls the brightness.
If a 3-channel mapping is selected then set_rgb_values()
has to be used.
Calling set_rgbw_values()
with a 3-channel mapping will produce incorrect
results. Vice-versa if a 4-channel mapping is selected then
set_rgbw_values()
has to be used. Calling set_rgb_values()
with a
4-channel mapping will produce incorrect results.
The following constants are available for this function:
For mapping:
New in version 2.0.6 (Plugin).
BrickletLEDStrip.
get_channel_mapping
()¶Returns: |
|
---|
Returns the currently used channel mapping as set by set_channel_mapping()
.
The following constants are available for this function:
For mapping:
New in version 2.0.6 (Plugin).
BrickletLEDStrip.
get_identity
()¶Return Object: |
|
---|
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.
BrickletLEDStrip.
register_callback
(callback_id, function)¶Parameters: |
|
---|---|
Returns: |
|
Registers the given function
with the given callback_id
.
The available callback IDs with corresponding function signatures are listed below.
BrickletLEDStrip.
enable_frame_rendered_callback
()¶Returns: |
|
---|
Enables the CALLBACK_FRAME_RENDERED
callback.
By default the callback is enabled.
New in version 2.0.6 (Plugin).
BrickletLEDStrip.
disable_frame_rendered_callback
()¶Returns: |
|
---|
Disables the CALLBACK_FRAME_RENDERED
callback.
By default the callback is enabled.
New in version 2.0.6 (Plugin).
BrickletLEDStrip.
is_frame_rendered_callback_enabled
()¶Returns: |
|
---|
Returns true if the CALLBACK_FRAME_RENDERED
callback is enabled, false otherwise.
New in version 2.0.6 (Plugin).
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:
def my_callback(param):
print(param)
led_strip.register_callback(BrickletLEDStrip.CALLBACK_EXAMPLE, my_callback)
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.
BrickletLEDStrip.
CALLBACK_FRAME_RENDERED
¶Callback Parameters: |
|
---|
This callback is triggered directly after a new frame is rendered. The parameter is the number of RGB or RGBW LEDs in that frame.
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()
.
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.
BrickletLEDStrip.
get_api_version
()¶Return Object: |
|
---|
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.
BrickletLEDStrip.
get_response_expected
(function_id)¶Parameters: |
|
---|---|
Returns: |
|
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:
BrickletLEDStrip.
set_response_expected
(function_id, response_expected)¶Parameters: |
|
---|---|
Returns: |
|
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:
BrickletLEDStrip.
set_response_expected_all
(response_expected)¶Parameters: |
|
---|---|
Returns: |
|
Changes the response expected flag for all setter and callback configuration functions of this device at once.
BrickletLEDStrip.
DEVICE_IDENTIFIER
¶This constant is used to identify a LED Strip 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.
BrickletLEDStrip.
DEVICE_DISPLAY_NAME
¶This constant represents the human readable name of a LED Strip Bricklet.