WS2812 LED failure

[thm_w]

How do you know that’s not super distracting to some people? Just because it’s not distracting to you doesn’t mean it’s not super distracting to me and others. You don’t get to decide what other people find distracting!!!

If a distraction draws my attention toward it when it shouldn’t — and those trails of dots very much do — then it is “affecting my vision of other objects” (by affecting perception) and introducing a hazard.

I completely believe that for you, it is a concern.
I don't believe there is evidence shown yet that commercial design should need to use greater than 1kHz PWM.

I tried last night when riding in the dark to see any sort of tails coming off of brake lights or street lamps, and could not see anything (this is just an anecdote, not proof of anything, I have other vision issues of course). So there must be some variability in when and where these are seen. The usual waving a LED around is an easy way to see a trail, but, nothing moves that fast on the road that I am aware of.

I wonder if it is related to this: https://eyewiki.aao.org/Palinopsia
This user is saying they see tails of light even during the day: https://www.reddit.com/r/visualsnow/comments/qdicr4/this_sub_is_filled_with_people_confusing/hhn6tnm/

https://link.springer.com/article/10.3758/BF03210418

[tooki]

How do you know that’s not super distracting to some people? Just because it’s not distracting to you doesn’t mean it’s not super distracting to me and others. You don’t get to decide what other people find distracting!!!

If a distraction draws my attention toward it when it shouldn’t — and those trails of dots very much do — then it is “affecting my vision of other objects” (by affecting perception) and introducing a hazard.

I completely believe that for you, it is a concern.
I don't believe there is evidence shown yet that commercial design should need to use greater than 1kHz PWM.

1. It’s not just me. In many discussions here, others have said the same thing, and you can easily find many, many, many other people online complaining about the same thing.
2. I honestly don’t know whether you intend this or not, but you come off as quite condescending and patronizing in your tone.
3. Other than appearing patronizing, what’s your intent with the links at the end? To suggest those of us who see the phantom array effect are just making it up? You do realize that you can capture the phantom array effect on video and photos, right?

I tried last night when riding in the dark to see any sort of tails coming off of brake lights or street lamps, and could not see anything (this is just an anecdote, not proof of anything, I have other vision issues of course). So there must be some variability in when and where these are seen. The usual waving a LED around is an easy way to see a trail, but, nothing moves that fast on the road that I am aware of.

Your eyes do: the angular velocity while saccading. This is not hypothetical, it’s been studied.

Now, I doubt much more than 2-3kHz would be necessary to eliminate it in all but the extreme edge cases. But many tail lights seem to be at extremely low frequencies, between 100-300Hz. (100Hz was apparently used in some cars with incandescent tail lights, so the 100Hz LEDs likely just have unmodified drivers.)

For example, here are two reference designs for automotive tail lights, from two different manufacturers (!) both using 200Hz:
https://www.ti.com/lit/ug/tidub07/tidub07.pdf?ts=1666962921720
https://www.maximintegrated.com/en/design/technical-documents/app-notes/4/4316.html

Here’s a patent for PWMed LED tail lights (why a patent like this was ever granted is another issue — everything in it is obvious), and it says… “200-300Hz”… “to ensure that no flicker is visible”: https://patents.google.com/patent/EP1459599B2/en

Clearly there’s a widespread belief that a few hundred hertz are enough to not create visible flicker, despite this being demonstrably, provably wrong as a blanket statement, since many people do report visible flicker.

Here’s a link to a scientific paper on the subject: “Flicker can be perceived during saccades at frequencies in excess of 1 kHz”
https://web.archive.org/web/20170325051112if_/http://www.essex.ac.uk/psychology/overlays/2013-207.pdf