Light painting text

I was making some updates to the “scrolling text marquee” pattern (thanks @zeb for the bug fix) and added a 1D render which lets you light-paint text in long exposure:

Or shake by hand for a little PoV:

I’m using this 128 LED bar from Adafruit, which is super dense at 320 LEDs/m. Warning: it came pre-wired with the connector reversed from most strips I’ve encountered. I almost blew it up. Have fun swapping JST SM pins.

The Adafruit description says it’s not good for PoV, but I also feel like these light paintings hint at something being a little off, either in code (note consistent delays at the top of the “H” and "l"s) or with transmission far down strip (note the late blue pixel).

Wizard updated the code upload for me in the pattern library.

@Troy I remember you were working on a light painting wand. Did you ever take some photogrpahs?


Ooh, did you try this on the ceiling fan project? I’m adding this to the list of things to try on my fan.

Hi @jeff,
Thats really cool! You just hit one of my PB bucket list items :slight_smile:

I have a theory on the straggler pixels. There are varying opinions on edge case (as in the tail edge) requirements of apa102 and/or clones (which may be the source of the differing viewpoints) - some say that you should clock out a bunch of dummy pixels based on the total length after the last pixel as they have some kind of cascading clock latch issue. I have code in place to do this (and this happens to be the cause of trailing white pixels if your count is set up short), but perhaps your LEDs need a bit more data.

I’d try increasing your pixel config a bit and seeing if it goes away or moves down.

It could also be the OS taking over the CPU for a bit to handle WiFi or something.

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A ceiling fan setup is on my bucket list.