LED Spaghetti V2

This is a flexible and translucent LED display panel, with 32x32 WS2812B compatible LEDs in series.

• The cutouts in the Flex PCB acount for ~45% of the total surface area, which provides decent visibility through the panel.
• Each panel draws ~500mA when +5V is applied but LED output is commanded off.
• The design is such that each pair of LED strips can be individually trimmed to length, and then entire strip pairs can be removed, only requiring 1 solder jumper per trim operation to be soldered closed. Cuttable areas are indicated by silkscreen lines.

For details about the design process, please read my blog posts on this project development starting here.

The schematic is extremely simple, and takes advantage of the reuse block feature to copy and paste the same 2x32 pixel strip 16 times, until the full 32x32 matrix is created. The block is composed of 16 2x2 LED units as shown below, each with two decoupling capacitors and one solder jumper for reconnecting the data line after trimming. These units are repeated downwards identically:

Then, this reuse block is copied 16 times as shown, with appropriate solder jumpers between each additional block to reconnecto the last data line if any of the 2x32 strips are trimmed off:

Please open the project in the editor to see the full schematics, but there is only more of the same.

Notes:

This is a proof of concept project, and is intended to offer a development platform to test ideas with before designing a custom PCB to better suite the application. This design has several known flaws, but it does work well enough to be used for a prototype in a pinch. It is highly recommended to be proficient in microsoldering when ordering this design, as the PCB will likely require rework due to the substantial quantity and small size of the solder joints/components.

The first run of boards were ordered with 2 layer 0.2mm thick polyimide FPC, 1oz copper, black coverlay, and no stiffener.