These can also be purchased at Wired Watts: https://www.wiredwatts.com/klk32b along with pixels, mounting plates, power supplies, etc…
What is it?
The K32A-B is a cape for the BeagleBone Black designed to drive ws2811 LED pixels. It has 32 local ports (fused with LED indicators) that can each drive 800 pixels (with power injection) at 40FPS. It also has 4 RJ45 differential ports that can output an additional 16 strings. Finally, it has 2 RS485 outputs for DMX, PixelNet, Renard, LOR.
For end-user usability, it provides a Real Time Clock, temperature sensors, voltage sensors, a header for an OLED display, four push buttons for navigating menus on the display.
The K32A-B also has an on-board, high quality DAC chip for providing sound.
It also has two extra headers for additional functionality. One header provides access to the I2C bus and 8 GPIO pins for additional push buttons or other triggers a user may need. The other header provides a mounting point for an optional Si4713 based FM transmitter.
Why did you make it?
Animated Christmas Light displays typically use ws2811 Pixels for things like house outlines, candy canes, tree’s, etc… The K32A-B was designed to drive a large number of pixels for dense props like MegaTree’s and matrices where having a lot of local ports is useful.
NOTE: The optional FM transmitter will NOT come with any sort of antenna attached. The user will need to create a suitable antenna (a simple 75cm wire will work for most cases) and solder it to the transmitter.
The FM transmitter requires the Si4713/VAST-FM FPP Plugin to be installed in order to configure and enable the the FM transmission.
What makes it special?
The 32 local ports provides more outputs than most controllers providing the ability to run a lot of pixels for dense props.
The 4 RJ45 ports provide additional output capabilities to allow for future expansions. All 4 of the ports can be configured to drive a ws2811 pixel differential receiver board (available from pixelcontroller.com ). Both the “Smart Receivers” and the normal receivers are supported.
The BeagleBone can be powered by the same power supply powering the pixels. There are jumpers on the board to select either 5V or 12V power. Alternatively, the BeagleBone can be powered by its own barrel connector if an on-board jumper is removed.
Technical details: Both the DMX and ws2811 protocols are extremely timing dependent and are generally not drivable via a general purpose Linux CPU. The FPP software uses the two semi real-time PRU’s available on the PocketBeagle to handle the protocol specific timings. One PRU is used for the ws2811 protocol strings and the other PRU is used for the DMX timings. Using the PRU’s also allows the main CPU to be free for other things such as network IO.
You WILL need:
- ws2811 pixels
- A good quality SD card with the latest FPP image installed on it. The latest FPP image can always be found at http://dankulp.com/bbb/
- A BeagleBone Black, BeagleBone Black Wireless, BeagleBone Green, or SanCloud BeagleBone enhanced.
Note: a BeagleBone Green Wireless will NOT work.