MQTT - LED Strip Bricklet 2.0¶

Simple¶

Download (example-simple.txt)

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# Change XYZ to the UID of your LED Strip Bricklet 2.0

setup:
    # Set first 3 LEDs to red, green and blue
    publish '{"index": 0, "value": [255,0,0,0,255,0,0,0,255]}' to tinkerforge/request/led_strip_v2_bricklet/XYZ/set_led_values

Callback¶

Download (example-callback.txt)

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# FIXME: This example is incomplete
# Change XYZ to the UID of your LED Strip Bricklet 2.0

setup:
    # Set frame duration to 50ms (20 frames per second)
    publish '{"duration": 50}' to tinkerforge/request/led_strip_v2_bricklet/XYZ/set_frame_duration

    # Use frame started callback to move the active LED every frame
    subscribe to tinkerforge/callback/led_strip_v2_bricklet/XYZ/frame_started
    publish '{"register": true}' to tinkerforge/register/led_strip_v2_bricklet/XYZ/frame_started # Register frame_started callback

Basic Functions¶

request/led_strip_v2_bricklet/<UID>/set_led_values¶

Request:	index – Type: int, Range: [0 to 6144] value – Type: [int, ...], Length: variable, Range: [0 to 255]
Response:	no response

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 request/led_strip_v2_bricklet/<UID>/set_chip_type) and a channel mapping (see request/led_strip_v2_bricklet/<UID>/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 request/led_strip_v2_bricklet/<UID>/set_frame_duration).

Generic approach:

• Set the frame duration to a value that represents the number of frames per second you want to achieve.
• Set all of the LED colors for one frame.
• Wait for the register/led_strip_v2_bricklet/<UID>/frame_started callback.
• Set all of the LED colors for next frame.
• Wait for the register/led_strip_v2_bricklet/<UID>/frame_started callback.
• And so on.

This approach ensures that you can change the LED colors with a fixed frame rate.

request/led_strip_v2_bricklet/<UID>/get_led_values¶

Request:	index – Type: int, Range: [0 to 6144] length – Type: int, Range: [0 to 6144]
Response:	value – Type: [int, ...], Length: variable, Range: [0 to 255]

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)).

request/led_strip_v2_bricklet/<UID>/set_frame_duration¶

Request:	duration – Type: int, Unit: 1 ms, Range: [0 to 216 - 1], Default: 100
Response:	no response

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 request/led_strip_v2_bricklet/<UID>/set_led_values.

Default value: 100ms (10 frames per second).

request/led_strip_v2_bricklet/<UID>/get_frame_duration¶

Request:	empty payload
Response:	duration – Type: int, Unit: 1 ms, Range: [0 to 216 - 1], Default: 100

Returns the frame duration as set by request/led_strip_v2_bricklet/<UID>/set_frame_duration.

request/led_strip_v2_bricklet/<UID>/get_supply_voltage¶

Request:	empty payload
Response:	voltage – Type: int, Unit: 1 mV, Range: [0 to 216 - 1]

Returns the current supply voltage of the LEDs.

request/led_strip_v2_bricklet/<UID>/set_clock_frequency¶

Request:	frequency – Type: int, Unit: 1 Hz, Range: [10000 to 2000000], Default: 1666666
Response:	no response

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 request/led_strip_v2_bricklet/<UID>/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.

request/led_strip_v2_bricklet/<UID>/get_clock_frequency¶

Request:	empty payload
Response:	frequency – Type: int, Unit: 1 Hz, Range: [10000 to 2000000], Default: 1666666

Returns the currently used clock frequency as set by request/led_strip_v2_bricklet/<UID>/set_clock_frequency.

request/led_strip_v2_bricklet/<UID>/set_chip_type¶

Request:	chip – Type: int, Range: See symbols, Default: 2801
Response:	no response

Sets the type of the LED driver chip. We currently support the chips

• WS2801,
• WS2811,
• WS2812 / SK6812 / NeoPixel RGB,
• SK6812RGBW / NeoPixel RGBW (Chip Type = WS2812),
• WS2813 / WS2815 (Chip Type = WS2812)
• LPD8806 and
• APA102 / DotStar.

The following symbols are available for this function:

For chip:

• "ws2801" = 2801
• "ws2811" = 2811
• "ws2812" = 2812
• "lpd8806" = 8806
• "apa102" = 102

request/led_strip_v2_bricklet/<UID>/get_chip_type¶

Request:	empty payload
Response:	chip – Type: int, Range: See symbols, Default: 2801

Returns the currently used chip type as set by request/led_strip_v2_bricklet/<UID>/set_chip_type.

The following symbols are available for this function:

For chip:

• "ws2801" = 2801
• "ws2811" = 2811
• "ws2812" = 2812
• "lpd8806" = 8806
• "apa102" = 102

request/led_strip_v2_bricklet/<UID>/set_channel_mapping¶

Request:	mapping – Type: int, Range: See symbols, Default: 36
Response:	no response

Sets the channel mapping for the connected LEDs.

If the mapping has 4 colors, the function request/led_strip_v2_bricklet/<UID>/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 symbols are available for this function:

For mapping:

• "rgb" = 6
• "rbg" = 9
• "brg" = 33
• "bgr" = 36
• "grb" = 18
• "gbr" = 24
• "rgbw" = 27
• "rgwb" = 30
• "rbgw" = 39
• "rbwg" = 45
• "rwgb" = 54
• "rwbg" = 57
• "grwb" = 78
• "grbw" = 75
• "gbwr" = 108
• "gbrw" = 99
• "gwbr" = 120
• "gwrb" = 114
• "brgw" = 135
• "brwg" = 141
• "bgrw" = 147
• "bgwr" = 156
• "bwrg" = 177
• "bwgr" = 180
• "wrbg" = 201
• "wrgb" = 198
• "wgbr" = 216
• "wgrb" = 210
• "wbgr" = 228
• "wbrg" = 225

request/led_strip_v2_bricklet/<UID>/get_channel_mapping¶

Request:	empty payload
Response:	mapping – Type: int, Range: See symbols, Default: 36

Returns the currently used channel mapping as set by request/led_strip_v2_bricklet/<UID>/set_channel_mapping.

The following symbols are available for this function:

For mapping:

• "rgb" = 6
• "rbg" = 9
• "brg" = 33
• "bgr" = 36
• "grb" = 18
• "gbr" = 24
• "rgbw" = 27
• "rgwb" = 30
• "rbgw" = 39
• "rbwg" = 45
• "rwgb" = 54
• "rwbg" = 57
• "grwb" = 78
• "grbw" = 75
• "gbwr" = 108
• "gbrw" = 99
• "gwbr" = 120
• "gwrb" = 114
• "brgw" = 135
• "brwg" = 141
• "bgrw" = 147
• "bgwr" = 156
• "bwrg" = 177
• "bwgr" = 180
• "wrbg" = 201
• "wrgb" = 198
• "wgbr" = 216
• "wgrb" = 210
• "wbgr" = 228
• "wbrg" = 225

Advanced Functions¶

request/led_strip_v2_bricklet/<UID>/get_spitfp_error_count¶

Request:	empty payload
Response:	error_count_ack_checksum – Type: int, Range: [0 to 232 - 1] error_count_message_checksum – Type: int, Range: [0 to 232 - 1] error_count_frame – Type: int, Range: [0 to 232 - 1] error_count_overflow – Type: int, Range: [0 to 232 - 1]

Returns the error count for the communication between Brick and Bricklet.

The errors are divided into

• ACK checksum errors,
• message checksum errors,
• framing errors and
• overflow errors.

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.

request/led_strip_v2_bricklet/<UID>/set_status_led_config¶

Request:	config – Type: int, Range: See symbols, Default: 3
Response:	no response

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 symbols are available for this function:

For config:

• "off" = 0
• "on" = 1
• "show_heartbeat" = 2
• "show_status" = 3

request/led_strip_v2_bricklet/<UID>/get_status_led_config¶

Request:	empty payload
Response:	config – Type: int, Range: See symbols, Default: 3

Returns the configuration as set by request/led_strip_v2_bricklet/<UID>/set_status_led_config

The following symbols are available for this function:

For config:

• "off" = 0
• "on" = 1
• "show_heartbeat" = 2
• "show_status" = 3

request/led_strip_v2_bricklet/<UID>/get_chip_temperature¶

Request:	empty payload
Response:	temperature – Type: int, Unit: 1 °C, Range: [-215 to 215 - 1]

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.

request/led_strip_v2_bricklet/<UID>/reset¶

Request:	empty payload
Response:	no response

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!

request/led_strip_v2_bricklet/<UID>/get_identity¶

Request:

empty payload

Response:

uid – Type: string, Length: up to 8 connected_uid – Type: string, Length: up to 8 position – Type: char, Range: ["a" to "h", "z"] 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] 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] device_identifier – Type: int, Range: [0 to 216 - 1] _display_name – Type: string

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. If symbolic output is not disabled, the device identifier is mapped to the corresponding name in the format used in topics.

The display name contains the LED Strip 2.0's name in a human readable form.

Callback Configuration Functions¶

request/led_strip_v2_bricklet/<UID>/set_frame_started_callback_configuration¶

Request:	enable – Type: bool, Default: true
Response:	no response

Enables/disables the register/led_strip_v2_bricklet/<UID>/frame_started callback.

request/led_strip_v2_bricklet/<UID>/get_frame_started_callback_configuration¶

Request:	empty payload
Response:	enable – Type: bool, Default: true

Returns the configuration as set by request/led_strip_v2_bricklet/<UID>/set_frame_started_callback_configuration.

Callbacks¶

Callbacks can be registered to receive time critical or recurring data from the device. The registration is done with the corresponding .../register/... topic and an optional suffix. This suffix can be used to deregister the callback later.

register/led_strip_v2_bricklet/<UID>/frame_started¶

Register Request:	register – Type: bool
Callback Response:	length – Type: int, Range: [0 to 6144]

A callback can be registered for this event by publishing to the .../register/led_strip_v2_bricklet/<UID>/frame_started[/<SUFFIX>] topic with the payload "true". An added callback can be removed by publishing to the same topic with the payload "false". To support multiple (de)registrations, e.g. for message filtering, an optional suffix can be used.

If the callback is triggered, a message with it's payload is published under the corresponding .../callback/led_strip_v2_bricklet/<UID>/frame_started[/<SUFFIX>] topic for each registered suffix.

This callback is triggered directly after a new frame render is started. The callback payload 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 request/led_strip_v2_bricklet/<UID>/set_led_values.

Internal Functions¶

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.

request/led_strip_v2_bricklet/<UID>/set_bootloader_mode¶

Request:	mode – Type: int, Range: See symbols
Response:	status – Type: int, Range: See symbols

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 symbols are available for this function:

For mode:

• "bootloader" = 0
• "firmware" = 1
• "bootloader_wait_for_reboot" = 2
• "firmware_wait_for_reboot" = 3
• "firmware_wait_for_erase_and_reboot" = 4

For status:

• "ok" = 0
• "invalid_mode" = 1
• "no_change" = 2
• "entry_function_not_present" = 3
• "device_identifier_incorrect" = 4
• "crc_mismatch" = 5

request/led_strip_v2_bricklet/<UID>/get_bootloader_mode¶

Request:	empty payload
Response:	mode – Type: int, Range: See symbols

Returns the current bootloader mode, see request/led_strip_v2_bricklet/<UID>/set_bootloader_mode.

The following symbols are available for this function:

For mode:

• "bootloader" = 0
• "firmware" = 1
• "bootloader_wait_for_reboot" = 2
• "firmware_wait_for_reboot" = 3
• "firmware_wait_for_erase_and_reboot" = 4

request/led_strip_v2_bricklet/<UID>/set_write_firmware_pointer¶

Request:	pointer – Type: int, Unit: 1 B, Range: [0 to 232 - 1]
Response:	no response

Sets the firmware pointer for request/led_strip_v2_bricklet/<UID>/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.

request/led_strip_v2_bricklet/<UID>/write_firmware¶

Request:	data – Type: [int, ...], Length: 64, Range: [0 to 255]
Response:	status – Type: int, Range: [0 to 255]

Writes 64 Bytes of firmware at the position as written by request/led_strip_v2_bricklet/<UID>/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.

request/led_strip_v2_bricklet/<UID>/write_uid¶

Request:	uid – Type: int, Range: [0 to 232 - 1]
Response:	no response

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.

request/led_strip_v2_bricklet/<UID>/read_uid¶

Request:	empty payload
Response:	uid – Type: int, Range: [0 to 232 - 1]

Returns the current UID as an integer. Encode as Base58 to get the usual string version.