lightkraken.net

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==== What is this? ====

Lightkraken is a PoE++ (802.3bt Type 4) powered LED strip driver.

* Up to 70W of power+data through a single standard Cat5 network cable
  * Supports ArtNet and E1.13 protocols
  * Supports most common programmable strips (WS2812b, APA102 etc.) or can drive analog RGB(W) strips using PWM at 14 bit resolution
  * 5V/12V/24V output selectable with a switch
  * web configurator built into device

==== PoE Power ====
Fully compatible with switches which support the following PoE standards:

* 802.3bt Type 4 "PoE++" (70W max)
  * 802.3bt Type 3 "4PPoE" (50W max)
  * 802.3at Type 2 "PoE+" (25W max)
  * 802.3af (802.3at Type 1) "PoE" (12.5W max)

=== Implementation ===

The PoE section of the Lightkraken board is based on a [[https://www.bourns.com/docs/Product-Datasheets/sm51625el.pdf|Bourns SM51625EL]] transformer and [[http://www.ti.com/lit/ds/symlink/tps2372.pdf|Texas Instrument TPS2372 PoE PD interface]]. It is rated for 70W of power, or 1.2A at the input.

The rectifier uses two [[https://www.mouser.jp/datasheet/2/149/FDMQ8205A-1079456.pdf|Fairchild FDMQ8205A MOSFET bridge]] ICs. During prototyping it was determined that using Schottky or regular diodes (to reduce cost) for the rectifier section generated too much heat. The use of the FDMQ8205A part is recommended in the Texas Instruments application notes.

==== Output power modes ====

* 5.4V @ 10A (54W)
  * 12V @ 5.8A (70W)
  * 23.5V @ 3A (70W)

There is a 3-position switch on the board which allows you to select the output voltage. Left position is 5.4V, middle is 12V and right position is 23.5V.

5.4V was selected instead of 5V to slightly extend the physical range of addressable LEDs without color change due to voltage drop. Virtually all LED chips rated for 5V also support 5.4V without any negative effects.

If you drive your LEDs at 25W or higher it is recommended to install a fan as the DC/DC conversion section on the board can become rather hot without one (I measured 100C/212F in open air, this will be much higher in an enclosed space). The board comes with a standard JST XH2.54-2P fan header, readily available 30x30x10mm fans work fine.

=== Implementation ===

The DC/DC converter section of the Lightkraken board uses a [[https://www.vishay.com/docs/65124/sic46x.pdf|Vishay SiC461 DC/DC Converter]]. It is rated for 10A of power. The inductor is an oversized [[https://datasheet.lcsc.com/szlcsc/1912111437_TAITEC-TMPA1707SP-6R8MN-D_C357121.pdf|TAITEC 6.8uH]] part, rated for up to 22A.

==== Networking ====

* 100/10Mbit ethernet
  * single RJ45 connector
  * DHCP (default) or static IP address. IPv4 only.
  * Each device has a unique MAC (LAA) address and host name
  * Each device has a built-in web configuration page. No public internet connection is required.
  * ArtNet and E1.31
  * Each device supports up to 5 universes per output. For RGB strips that means up to 1020 LEDs per output (see "Reality Check" below)
  * Accepts unicast or broadcast ArtNet packets
  * Accepts unicast E1.31 traffic and joins E1.31 multicast address space by default
  * Supports ArtNet and E1.31 synchronization packets

=== Implementation ===

The ethernet interface uses a [[http://ww1.microchip.com/downloads/en/devicedoc/8720a.pdf|LAN8720A]] IC which operates in RMII mode only.

The microcontroller is a [[https://datasheet.lcsc.com/szlcsc/GigaDevice-Semicon-Beijing-GD32F130G8U6_C94321.pdf|GigaDevice GD32F107RCT6]] Cortex-M3 part. The part was chosen because of physical package, RAM size and low cost. Unfortunately ST does not provide an equivalent part, 64KB of RAM is way too small for this application. LwIP, the TCP/IP stack used, consumes about 50KB RAM alone in the latest version which leaves little room for client code.

Unique MAC addresses are generated by computing a 32-bit hash of the UID of the microcontroller and using a fixed LAA prefix.
==== Data input modes ====

* RGB 8-bit sequential DMX data. RGB is automatically converted to RGBW if such a strip is used.
  * RGBW 8-bit sequential DMX data. RGBW is automatically converted to RGB if such a strip is used.
  * sRGB 8-bit sequential DMX data. This will convert the received data using the reverse sRGB transfer function ("gamma correction").

==== Reality check ====

54W@5V and 70W@12V is not a lot in the grand scheme of things. While Lightkraken supports up to 5 universes per output, don't expect to be able to drive LEDs at full brightness using this configuration. Realistically expect 1 universe (~256 LEDs) per Lightkraken device at full brightness. I have tested one of these](https://www.amazon.com/gp/product/B07417BRFN) successfully on a POE-171A-95 switch for several weeks. YMMV will vary of course as all LEDs out there vary in specifications.

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