I’m working on a custom PCB for a decoration, and ideally it has a nice broad spectrum warm white colour (so a protocol with RGBW capability) and also looks good when being filmed or moving. I’ve been looking at the two wire (clock and data) protocols like APA107 or SK9822, but I can’t find any that are capable of RGBW.
On the other hand I’ve been looking at the WS2814 IC, which has RGBW output, but the slower refresh time is less ideal for filming.
I’m quite comfortable having the LED driver IC external to the LED themselves if that’s the best option, as I’ll be ordering the whole PCB from scratch anyway. Are there perhaps other tricks I could use on the PCB to smooth out the flickering, such as capacitors in line with the LED itself?
A bit unrelated but just in case, anyone know any good sources for individual 5050 SMD RGBW LEDs, with a warm white with a high CRI? I’ll be ordering the PCBs assembled on JLCPCB.
Sorry when you say “smooth out the flickering” are you talking about what your eye sees or the camera?
For your eyes, there shouldn’t be any noticeable “flicker” unless it’s builtin to the effects your running or you have a power/wiring/design problem.
For the camera, that’s a much bigger ask.
A camera can be much better at capturing high speed events than the human eye and will often “see” the intermediate steps in the LED strip while an image/effect is being “built”.
Going the SK9822 route is probably a good choice, but may not solve all the issues as WLED does end up with a max software refresh rate that can be down at 50fps (or less). That depends on the # of LEDs, and the effect(s) you’re trying to drive.
As you noted, the inherent refresh time of the WS281x types are slower, and there’s not much you can do about that.
Thanks! Yeah exactly, my worry is mostly flickering for cameras rather than for eyes. I’ve seen the APA102s/SK9822 used in several persistence of vision projects which gives me confidence with them, but there’s no version with a white channel right?
Don’t know of one off hand that has RGBW in one LED, but there are W only variants.
You end up with RGB and 1 (or more) separate white strips - or even interlaced on the same strip.