Skip to content

Home

Jump to bottom
Paul edited this page Feb 23, 2022 · 7 revisions

LED Extender boards

Dr Oldies LED Extender Teensy shields and non-shields are small, inexpensive expansion boards which support up to 16 leds strips in either simple strips or tiled arrays

Schematics, Gerbers, BOM and Pick List files are included

Figure: Panel of 3072 leds of 48 8x8 tiles
  • LED Extender PCBs can be used independently or, more conveniently, with my LEDMatrix_22/FastLED library.
  • Combining the Extenders with these libraries allows you to design medium to large led strings and arrays of 4096 leds and more.
  • Large led panels can be composed of multiple led tiles in numerous arrangements.
  • Versions support both 1-wire and 2-wire leds (see below).
  • Using a multiplexing schema large 2-wire arrays use 8 MCU pins or less! Leaving lots of pins for sound and other uses.
  • The LEDMatrix_22 library is configured in a well documented header file.
  • 3v3 data lines are converted to 5v while isolating the MCU from led voltages.
  • See the Wiki above for complete details
  • All gerber, BOM, and Pick Lists files are included.
  • Includes DipTrace schematic and board files. (DipTrace is free to download for smaller PCBs)

The Problem

Both 1-wire (data only) and 2-wire (data + clock) led strips longer than a few dozens of leds fall out of sync and begin to "pixilate" or flash randomly. Using voltage steppers to ensure full 5v signals and even injecting additional current to sustain brightness of leds can help to some extent. But out of sync timing still occurs. Breaking led strips into shorter led strips running in parallel from the MCU required complicated code, and uses a large number of MCU pins.

The Solution

These LED Extenders allow you to break-up the strings into shorter strips running in parallel by multiplexing a minimum of MCU output pins to a large number of strips.

Image of Teensy stacked on top of 4 "4x 2-wire shields." Using 8 Teensy pins output is 16 DATA+CLOCK lines to 16 led tiles. Extended female headers send current and data through all 4 shields.

  1. Teensy 3.5 to 4.1 in plug-and-play shield format Plug Teensy directly into the shield, either above or below 1 to 4 extenders can be added ("long leg" female headers required) for up 10 16 strings

  2. Non-shield format for other MCUs 32 bit MCU recommended for larger LED matrices Sufficient memory to accommodate the CRGB LED array Requires jumper wires or ribbon cable-not supplied

Definitions: Panel Final led Array composed up to 16 Banks Bank Up to 4 separate strings of leds in any simple strings or Tiles Tiles Leds arranged in individual squares or rectangles. For example 8x8 tiles.

supported LEDs

LEDS (2-wire) using DATA and CLOCK pins (partial list)

LPD6803 
LPD8806 
WS2801
WS2803
SM16716
P9813  
DOTSTAR  
APA102  
SK9822

LEDS (1-wire) using DATA only pin (partial list) TX1813N1 TX1812 WS2811 WS2812 WS2812B WS2815

Any other dual pin LED supported by FastLED

Clone this wiki locally