A library for driving digital RGB(W) LEDs using the ESP32's RMT peripheral

Digital RGB(W) LED (WS2812/SK6812/NeoPixel/WS2813/etc.) library for the ESP32

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. So far I've tested 4 strands successfully.

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!

There are ESP-IDF SDK settings that need to be changed to equal the Arduino-ESP32 defaults. The Tick Rate and CPU Frequency need to be adjusted, otherwise the ESP-IDF build will run significantly more slowly.

Please see the sdkconfig.defaults file for details. 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?