Is there a standard or best practice for hooking up LED strips to Arduino’s or other controllers? I’ve seen many videos that show people using resistors inline with the data pin etc. But I’ve never been told why, I like to know why if that is best practice etc. What are the details behind which kind to use, depending on the length of strips, led count, what? Thanks.
I personally never used a resistor inline with the data pin and never experienced any problems with that. That being said, I think there are 2 main justifications for the use of a resistor inline:
The first has to do with circuit protection and is meant to limit the potential inrush current into an unpowered digital driver when it is connected to a powered strip. My solution here is to never connect/disconnect strips or RGB LEDs with power applied.
The second has to do with source and load impedance matching of data transmission lines. In most cases, this has just about no real influence in the data received by that first RGB LED unless the wire to that first pixel is really long and even there the ‘benefit’ of a resistor is questionable imho !
Length of strip & led count should have no influence on the choice of adding or not a resistor or it’s value.
I usually refer people to the Adafruit Neopixel Uber Guide for such questions:
JP’s point about in-rush current is the reason you should have the resistor inline with the data pin. As the data output pin can only source so much current with out damaging itself. The resistor to limit the current on the pin to protect it from damage.
@Trey_Coursey - I use the two resistor fix as show on:
https://forums.adafruit.com/viewtopic.php?f=47&t=50434&p=254414&hilit=ws2812.jpg#p254414
It works and I no longer have the problem of killing NeoPixels that I had before using the two resistor fix. It works for WS2811, too.