Works great with the library!
As a heads up: the pixels on these panels are arranged in a back-and-forth order like so:
A→ B→ C→ D↓
↓H ←G ←F ←E
I → J→ K→ L↓
P ←O ←N ←M
(A fancy word for this is “boustrophedon” - meaning ‘as the ox plows’, back and forth across a field.)
This panel also highlights a great use for the library’s new (free) “global dimming”, because at anything more than about 20% brightness these things are a little eyewatering: great for final application use… but a little taxing to stare at during hours of coding and testing. 256xWS2812s at full brightness make a nice way to turn several amps of current into about eleventy-seven pentagazillion photons.
ahh, so you’ve used these? how well do they update with a basically a single stream of 256 leds?
Dan and I have a couple, and we’ve powered them up and lit them with existing (linear) animations. They work fine, and look sort of cool and interesting. Seeing a linear animation that you developed now wrapped back and forth at 16-pixel fold points shows you patterns and harmonics in your animation that you might not see when it was just a strip.
It works fine, and it’s interesting and fun.
I have some 2D patterns that I’ve previously coded, but I haven’t ported them to this panel yet.
Sorry, maybe I missed the main question there. If you’re asking about timing, I suspect you can get >100 FPS for simple animations, and >30 FPS for more complicated ones-- depending of course on HOW complicated. Those speeds would be on an Arduino Uno or similar.
Basically, speed is the same as a linear strip of 256 WS2811/WS2812 pixels.
See also http://www.aliexpress.com/item/16-16pixels-WS2812-led-digital-flexible-panel-light-ws2811-IC-controlled-size-17cm-17cm-DC5V-input/825283258.html, if you want to deal with a known supplier; because shipping is separate, you can often save money if you are ordering multiple items from Ray. Ray also has it with an SD card based controller for $25 more, same shipping.
256 * 60ma = 15A full on. Use a good power supply, and wiring/PCB traces with enough ampacity and low enough resistive voltage drop.
256 * 30us/pixel = 7.68 ms to update all the pixels. That’s about 3 PWM cycles for the 2811, so you don’t need to worry about that. So the maximum possible update rate is about 130 fps (say, if it were DMA driven and the controller could set up the next frame as the current was being refreshed). Slower of course depending on how fast your controller can read/generate the next frame.
The big question with these is - what do you want to do with that much brightness in that small a space? The pixels are spaced about one per cm (remember that 5050’s are half a centimeter across) By the time you are far away enough to not be blinded, the pixels may be blending into each other.
One idea I had, but have not had time to implement, is using it with a fresnel lens to project onto the ceiling or wall, perhaps deliberately unfocused enough to have the blobs lightly overlap for continuous light.
What else is anyone using them for?
Zeph: funny you should mention a lens and projector… Would you believe that an old “Artoscope” projector has a 7"x7" image pickup area, which is just a tad larger than these LED panels? Coincidence, or DESTINY??
We didn’t hook up a 15A supply, so we couldn’t test full brightness, but even at 2A, it projected pretty well in a darkend room. I’m sort of dying to see how much light it throws his way.
Ray is our preferred, go to provider for LEDs - he was also the supplier for the chain of tm1829s that I have to play with.