ESP32 Digital RGB(W) LED Drivers

A library for driving self-timed digital RGB/RGBW LEDs (WS2812, SK6812, NeoPixel, WS2813, etc.) using the Espressif ESP32 microcontroller's RMT output peripheral

Based upon the ESP32 WS2812 driver work by Chris Osborn

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Notes

The RMT peripheral of the ESP32 is used for controlling up to 8 LED "strands" (in whatever form factor the serially-chained LEDs are placed). These strands are independently controlled and buffered.

There are working demos for Espressif's IoT Development Framework (esp-idf) and Arduino-ESP32 core. Some demos are ONLY for the ESP IDF (demonstrating C-only techniques). Otherwise, a given demo should be exactly the same on either framework.

This library currently works well with WS2812-type and NeoPixel RGB LEDs (3 bytes of data per LED) - SK6812 RGB LEDs should work equally well. This also works fine with WS2813 (the backup channel is not used currently - tie Backup In to Data In for now).

This also works well with SK6812 RGBW LEDs (4 bytes of data per LED). These are similar to the WS2812 LEDs, but with a white LED present as well - keep in mind that RGBW LEDs draw a fair amount of extra power versus the usual RGB LEDs due to the added white LED element present.

Timings for a given LED type can vary even within that line: use the version variant that works best for you (see ledParamsAll for details).

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ESP-IDF build notes - Important!

The ESP-IDF demos are WIP right now (not currently buildable) and may be that way indefinitely

The ESP-IDF varies so regularly and so significantly it's more difficult to keep up with it, versus the abstracted Arduino-ESP32 interfaces. As time permits, I'm working on making it buildable with v3.2.2 and later sub-versions but it's slow going.

While the Arduino-ESP32 side is my main focus, the ESP-IDF build ought to be very similar (demo*.ino --> main.cpp, and the header and source libs aren't in their canonical locations by default). Beyond convenience, there was no real value in maintaining duplicate copies of the code and libraries as I did previously so those duplicates were removed. Also, symlinks in the repo are specifically disallowed in Arduino so that's not happening.

Please see the sdkconfig.defaults file for details of the defaults I use. If you run make menuconfig or make sdkconfig this file will be parsed for initial settings ONLY if sdkconfig doesn't exist. However, this file will be processed every time you run make defconfig.

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TODO

• API (current):

  • init --> initStrands (all strands)
  • setColors --> update --> updatePixels (per strand)
  • (n/a) --> reset --> resetPixels (per strand)

• Future additional (class-driven):

  • (n/a) --> updateTimings (for fine-tuning, debugging, or marginal/odd devices)
  • (n/a) --> updateType (for fine-tuning, debugging, or marginal/odd devices)
  • (n/a) --> addStrand/deleteStrand? (maybe not...)

• Other:

  • Make the whole library a proper class - more robust and extensible!
  • ledParams - refine and clarify
  • ledParams - lower bounds? Currently bit timing constants are pre-padded +50ns
  • ledParams - add a small constant string as a mapping to the name?
    • Nope! C99 designator 'name' outside aggregate initializer
  • ledParams - instead of bytesPerPixel, specify color format (GRBW, RGB, etc.)?
    • Would have the same problem as naming...
  • WS2813 - handle backup channel
  • Resolve open TODOs in code
  • Add more interleaved demos, and more demos in general
  • Make Arduino side a true Arduino library? May not be practical.
  • APA102/DotStar support?