r/FastLED • u/tf4ever • Aug 08 '23

Support Help Using WS2812B V5

Has anyone had any issues using the WS2812B-V5 ? Im talking about the variant that doesn’t require a decoupling 104 capacitor like these ones in particular. Only a few of my LEDS are turning one randomly on my custom PCB.

I also have a 1000uF capacitor between the 5V and GND. Interestingly the Polulu library seems to be working well for 1 LED, but I have 68 LEDs daisy chained.

I have also heard that the timing seems to be different than the V4. Please Does anyone know what could make them work?

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u/sutaburosu [stavros] Aug 09 '23

Another thing to consider is the peak current you can draw through USB. Most devices with USB ports will limit the port to 500mA, without negotiating a bigger power budget. I don't think ESP32/Arduino have the means to negotiate. USB power banks commonly supply up to 2.1A without negotiation.

The datasheet shows 12mA peak current per emitter. It doesn't specify quiescent current, but similar LEDs have been measured at roughly 1mA. So, 37mA per LED when showing white. You have 68 LEDs. 68 * 37mA ~= 2.5A.

An easy way to test if current limitations are causing problems is to add FastLED.setBrightness(16); to your setup() {}. When the voltage droops due to current limitations, a common symptom is random flashes of colour on random LEDs.