Addressable LEDs over distance – update – with pictures

Made progress. Have tested a number of different configurations and now have something (renderings) to show for it. Thank you 3D Board Viewer for the images.

Reminder – long post about where this came from. Now it’s about building it.

The main board is simple with 2 LEDs on it. By default, it receives serial data, runs it through the LEDs (Neopixels), and then out the other side again as serial (rs485). There is the need to source the signal from a microcontroller. It was desirable to not make a special board for this. To that end, there are different traces on the board that can be cut to change the behavior of the one board. Cut a single trace and a pin (header of three pins) can be used as TTL data IN for the first LED. Cut a different trace and you bypass the LEDs but get the benefit of converting the TTL to serial for the benefit of the next board and so on in the chain. To make it even more fun cut a pair of traces and the IN and OUT of the board are now capable of driving an arbitrary local set of LEDs. To demonstrate this feature a mini shield board was designed with up to 8 LEDs on it. Solder pads on the shield can be used to select the number of LEDs you solder to it.
Raw parts and board costs for the main board are ~$10 currently. A run of many many boards and part selection optimization could bring this price point significantly lower. Price is noted here but not yet a critical goal.

“top” of main board This is the functional top of the board where the two default LEDs are mounted. Power and data come in and out the left and right sides of the board.
“bottom” of main board This is the functional bottom of the board.  You can see the voltage regulator and the optional traces / pads that can be cut to modify the features the board provides.

Don’t those look just fantastic?  Here is the board layout before it is rendered.

The raw board design before sent to manufacturer.

The shield was a fun bit to try to make. Again these boards are working only in theory today. Parts and boards are in the process of being made and shipped. Once they arrive soldering and testing of these final solutions will commence.

Here is a rendering of the shield with the accompanying board design image.

Rendering of the LED shield with connection headers to join to the main board.
Image of the shield board design. These images are screenshots from the Eagle PCB CAD design tool (free you should get a copy).