This is the description of the Python API bindings for the LED Strip Bricklet 2.0. General information and technical specifications for the LED Strip Bricklet 2.0 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 | #!/usr/bin/env python
# -*- coding: utf-8 -*-
HOST = "localhost"
PORT = 4223
UID = "XYZ" # Change XYZ to the UID of your LED Strip Bricklet 2.0
from tinkerforge.ip_connection import IPConnection
from tinkerforge.bricklet_led_strip_v2 import BrickletLEDStripV2
if __name__ == "__main__":
ipcon = IPConnection() # Create IP connection
ls = BrickletLEDStripV2(UID, ipcon) # Create device object
ipcon.connect(HOST, PORT) # Connect to brickd
# Don't use device before ipcon is connected
# Set first 3 LEDs to red, green and blue
ls.set_led_values(0, [255, 0, 0, 0, 255, 0, 0, 0, 255])
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 | #!/usr/bin/env python
# -*- coding: utf-8 -*-
HOST = "localhost"
PORT = 4223
UID = "XYZ" # Change XYZ to the UID of your LED Strip Bricklet 2.0
NUM_LEDS = 16
rgb = [0, 0, 0]*NUM_LEDS
index = 0
from tinkerforge.ip_connection import IPConnection
from tinkerforge.bricklet_led_strip_v2 import BrickletLEDStripV2
# Use frame started callback to move the active LED every frame
def cb_frame_started(length, ls):
global index
rgb[index] = 0
index += 3
if index >= NUM_LEDS:
index = 0
rgb[index] = 255
# Set new data for next render cycle
ls.set_led_values(0, rgb)
if __name__ == "__main__":
ipcon = IPConnection() # Create IP connection
ls = BrickletLEDStripV2(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 started callback to function cb_frame_started
ls.register_callback(ls.CALLBACK_FRAME_STARTED,
lambda x: cb_frame_started(x, ls))
# Set initial rgb values to get started
ls.set_led_values(0, rgb)
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.
BrickletLEDStripV2
(uid, ipcon)¶Parameters: |
|
---|---|
Returns: |
|
Creates an object with the unique device ID uid
:
led_strip_v2 = BrickletLEDStripV2("YOUR_DEVICE_UID", ipcon)
This object can then be used after the IP Connection is connected.
BrickletLEDStripV2.
set_led_values
(index, value)¶Parameters: |
|
---|---|
Returns: |
|
Sets the RGB(W) values for the LEDs starting from index. You can set at most 2048 RGB values or 1536 RGBW values (6144 byte each).
To make the colors show correctly you need to configure the chip type
(see set_chip_type()
) and a channel mapping (see set_channel_mapping()
)
according to the connected LEDs.
If the channel mapping has 3 colors, you need to give the data in the sequence RGBRGBRGB... if the channel mapping has 4 colors you need to give data in the sequence RGBWRGBWRGBW...
The data is double buffered and the colors will be transfered to the
LEDs when the next frame duration ends (see set_frame_duration()
).
Generic approach:
CALLBACK_FRAME_STARTED
callback.CALLBACK_FRAME_STARTED
callback.This approach ensures that you can change the LED colors with a fixed frame rate.
BrickletLEDStripV2.
get_led_values
(index, length)¶Parameters: |
|
---|---|
Returns: |
|
Returns length RGB(W) values starting from the given index.
If the channel mapping has 3 colors, you will get the data in the sequence RGBRGBRGB... if the channel mapping has 4 colors you will get the data in the sequence RGBWRGBWRGBW... (assuming you start at an index divisible by 3 (RGB) or 4 (RGBW)).
BrickletLEDStripV2.
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_led_values()
.
Default value: 100ms (10 frames per second).
BrickletLEDStripV2.
get_frame_duration
()¶Returns: |
|
---|
Returns the frame duration as set by set_frame_duration()
.
BrickletLEDStripV2.
get_supply_voltage
()¶Returns: |
|
---|
Returns the current supply voltage of the LEDs.
BrickletLEDStripV2.
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.
BrickletLEDStripV2.
get_clock_frequency
()¶Returns: |
|
---|
Returns the currently used clock frequency as set by set_clock_frequency()
.
BrickletLEDStripV2.
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:
BrickletLEDStripV2.
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:
BrickletLEDStripV2.
set_channel_mapping
(mapping)¶Parameters: |
|
---|---|
Returns: |
|
Sets the channel mapping for the connected LEDs.
If the mapping has 4 colors, the function set_led_values()
expects 4
values per pixel and if the mapping has 3 colors it expects 3 values per pixel.
The function always expects the order RGB(W). 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, then 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.
The following constants are available for this function:
For mapping:
BrickletLEDStripV2.
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:
BrickletLEDStripV2.
get_spitfp_error_count
()¶Return Object: |
|
---|
Returns the error count for the communication between Brick and Bricklet.
The errors are divided into
The errors counts are for errors that occur on the Bricklet side. All Bricks have a similar function that returns the errors on the Brick side.
BrickletLEDStripV2.
set_status_led_config
(config)¶Parameters: |
|
---|---|
Returns: |
|
Sets the status LED configuration. By default the LED shows communication traffic between Brick and Bricklet, it flickers once for every 10 received data packets.
You can also turn the LED permanently on/off or show a heartbeat.
If the Bricklet is in bootloader mode, the LED is will show heartbeat by default.
The following constants are available for this function:
For config:
BrickletLEDStripV2.
get_status_led_config
()¶Returns: |
|
---|
Returns the configuration as set by set_status_led_config()
The following constants are available for this function:
For config:
BrickletLEDStripV2.
get_chip_temperature
()¶Returns: |
|
---|
Returns the temperature as measured inside the microcontroller. The value returned is not the ambient temperature!
The temperature is only proportional to the real temperature and it has bad accuracy. Practically it is only useful as an indicator for temperature changes.
BrickletLEDStripV2.
reset
()¶Returns: |
|
---|
Calling this function will reset the Bricklet. All configurations will be lost.
After a reset you have to create new device objects, calling functions on the existing ones will result in undefined behavior!
BrickletLEDStripV2.
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.
BrickletLEDStripV2.
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.
BrickletLEDStripV2.
set_frame_started_callback_configuration
(enable)¶Parameters: |
|
---|---|
Returns: |
|
Enables/disables the CALLBACK_FRAME_STARTED
callback.
BrickletLEDStripV2.
get_frame_started_callback_configuration
()¶Returns: |
|
---|
Returns the configuration as set by
set_frame_started_callback_configuration()
.
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_v2.register_callback(BrickletLEDStripV2.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.
BrickletLEDStripV2.
CALLBACK_FRAME_STARTED
¶Callback Parameters: |
|
---|
This callback is triggered directly after a new frame render is started. The parameter is the number of 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_led_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.
BrickletLEDStripV2.
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.
BrickletLEDStripV2.
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:
BrickletLEDStripV2.
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:
BrickletLEDStripV2.
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.
Internal functions are used for maintenance tasks such as flashing a new firmware of changing the UID of a Bricklet. These task should be performed using Brick Viewer instead of using the internal functions directly.
BrickletLEDStripV2.
set_bootloader_mode
(mode)¶Parameters: |
|
---|---|
Returns: |
|
Sets the bootloader mode and returns the status after the requested mode change was instigated.
You can change from bootloader mode to firmware mode and vice versa. A change from bootloader mode to firmware mode will only take place if the entry function, device identifier and CRC are present and correct.
This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.
The following constants are available for this function:
For mode:
For status:
BrickletLEDStripV2.
get_bootloader_mode
()¶Returns: |
|
---|
Returns the current bootloader mode, see set_bootloader_mode()
.
The following constants are available for this function:
For mode:
BrickletLEDStripV2.
set_write_firmware_pointer
(pointer)¶Parameters: |
|
---|---|
Returns: |
|
Sets the firmware pointer for write_firmware()
. The pointer has
to be increased by chunks of size 64. The data is written to flash
every 4 chunks (which equals to one page of size 256).
This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.
BrickletLEDStripV2.
write_firmware
(data)¶Parameters: |
|
---|---|
Returns: |
|
Writes 64 Bytes of firmware at the position as written by
set_write_firmware_pointer()
before. The firmware is written
to flash every 4 chunks.
You can only write firmware in bootloader mode.
This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.
BrickletLEDStripV2.
write_uid
(uid)¶Parameters: |
|
---|---|
Returns: |
|
Writes a new UID into flash. If you want to set a new UID you have to decode the Base58 encoded UID string into an integer first.
We recommend that you use Brick Viewer to change the UID.
BrickletLEDStripV2.
read_uid
()¶Returns: |
|
---|
Returns the current UID as an integer. Encode as Base58 to get the usual string version.
BrickletLEDStripV2.
DEVICE_IDENTIFIER
¶This constant is used to identify a LED Strip Bricklet 2.0.
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.
BrickletLEDStripV2.
DEVICE_DISPLAY_NAME
¶This constant represents the human readable name of a LED Strip Bricklet 2.0.