I've been playing with a WS2812B RGB strip on an Arduino Nano / FastLED. Working great. I have a 470 Ohm resistor on the data line and a 1000uF cap across the power lines at the strip.
I understand that the resistor improves signal integrity, and the cap reduces noise on the power line.
We're going to be making a lot of these, and I'm wondering if I can possibly get away without those two components (it would ease assembly and installation). Main question: is this a circumstance where I can test it with my PSU and if it works, it works, and I can go ahead without them, or is this the kind of thing where it might work fine in the workshop and then when it goes somewhere else it starts picking up interference and the lights get wonky? I.e how intermittent are the kinds of problems that those components solve?
There are only something like 12 LEDs in the strip that will be in the final product, if that matters. It's a BTF lighting strip.
Yep, you can omit the cap and resistor, as long as you have a very short wire between the Arduino and the ledstrip. Study destructive spikes in transmission lines.
Leo..
Why is that cap a problem. A 6.3volt/470uF tantalum is 3x6mm.
A 100uF/6.3volt electrolytic cap isn't huge either.
As said, it will only be sort-off ok if the input of the LED strip is right next to the Arduino.
Any (long) wire between them could generate potentially destructive spikes.
Russial roulette for the first LED.
Leo..
The series resistor prevents "ringing" of the data line which would cause weird flickering of the LEDs. I had a setup on the bench when I was seeing fast, random flickering of the string. I added a 1K resistor in the data line and the flickering stopped. The size is not important- I've used whatever was handy from 220Ω to 10K.
Yeah it's not the end of the world if we need to include the cap; it's mostly about assembly complexity; trying to reduce the number of things that need to be sourced, soldered, etc.
@Wawa would you be comfortable putting a specific (rough) distance range on "right next to"?