DMX Shield Logic Converter Does Not Work With APA102 LED Strip

Other
1

Hi,

I use the DMX shield (https://www.sparkfun.com/products/15110) together with the advised ESP32 Thing Plus ( SparkFun Thing Plus - ESP32 WROOM (Micro-B)) and try to drive a strip of APA102 LEDs connected to the poke-home connectors. I read all the hookup guide for the DMX shield and tried to make the FastLED example ‘FirstLight’ work with the hardware setup. Of course I adjust the PIN numbers in the FastLED code example to

#define DATA_PIN 27
#define CLOCK_PIN 5
…
FastLED.addLeds<APA102, DATA_PIN, CLOCK_PIN, RGB>(leds, NUM_LEDS);

However I cannot get it to work. Neither on the poke-home connectors D2 and C2 nor on D1 and C1 nor on D0 and C0 with the corresponding PINs for Signal 19 and 18 in the FastLED code.

The LEDs will only work if I solder the APA102 LED strip signal and clock directly to PIN 27 and 5 on the ESP32 Thing Plus board.

I doubled checked everthing with a second DMX shield and also with another ESP32 board and a variety of different SPI LED strips and still found the same issue that the output with the poke-home connectors do not work.

Any idea what could be the issue?

2

I found the issue:

While a USB cable was attached to the ESP32 boards, the SPI based LED strips didn’t work.

However, when I disconnected the USB cable from my PC to the ESP32 the APA102 LEDs suddenly started to behave correctly.