I have a technical problem with the Sparkfun DMX shield (with ESP32 thing plus) and a addresable LED strip, that involve the wires from shield poke connectors to led strip.
When connecting WS2813 led strips to the DMX shield they do not work reliably. Either the whole strip doesn’t respond to the colors set by WLED firmware on the ESP32, or the first few leds do flicker white.
It has been discussed that using LED strips on ESP32 GPIOs need a level shifter to shift the 3.3 V logic signal up to 5 V logic signals. There is a level shifter on the sparkfun DMX shield ( SparkFun ESP32 Thing Plus DMX to LED Shield - SparkFun Electronics ) but I would argue that the type of levelshifter used there (TXB0104) is not suitable to reliably drive led strips.
It is mentioned in the WLED resources for example (Other Hardware - WLED Project) that the TXB or TXS bi-directional level shifters do work only in very limited conditions.
While some led strips (WS2812) would still work with the DMX shield supplied level shifter, they will stop working, especially when using longer data cables between DMX shield and led strip. From my own experience max 60 cm work for WS2811. However some other strips (APA102) will work only with much less cable lengths (DMX shield to addressable LED Problem with long wires).
Recently even less than 15 cm data cable didn’t work with my WS2813 led strips. Here I assume that they have somewhat tighter timings between data packets that the leds accept (WS2813 LED strip glitches after +- 1 hour - #4 by Deva_Rishi - General Electronics - Arduino Forum). This leads to not working correctly or worse not working at all situations, in my case.
So why did sparkfun opt for bi-directional TXB0104 level shifter on the DMX shield, when it is known that they are inferior to many others. And why would it be a bi-directional level shifter? Those DMX shield would alsways flow the signal in one direction. So bi-directionality is not needed here at all?
Anyone has similar experience with the DMX shield? Or a clever solution to still employ the otherwise very nice DMX shield?