Hi Awesome people! Working on Dr. Brainlove 2.0 EEG controlled lighting - Planning to switch to APA102 leds from WS2811 last year (unless there is something better already). We are figuring out overall architecture, thinking probably ethernet to teensy 3.1s, controlled from Processing and Max. Does anyone know offhand the max pixels/framerate we should expect from the Teensy/APA102s? I saw the chart on PJRC for the 2811s but wonder if it’s significantly different?
Thanks/Lemme know 
http://www.drbrainlove.org
APA102’s can run at 24Mhz - or approximately 750,000 RGB led pixel updates/second (assuming 100% cpu spent pushing data - I haven’t done DMA support for SPI based leds yet). WS2812’s are 800khz, or 33,333 RGB led pixel updates/second, or 266,664 RGB led pixel updates/second using the OctoWS2811 controller (though, in realitily probably about 10-20% less than that because there is still CPU time involved in prepping the data for parallel output).
It seems that with some of the APA102 strips, longer strips require lower clock rates, 8-12Mhz (which would have an appropriate tweak in frame rate), but given that I’ve run a board with 768 apa102’s on it at 24Mhz with no problems (and in theory, you can run them at 32Mhz, but the teensy 3.1 SPI rate taps out at 24), I suspect there’s wiring/power injection games that need to be played.
Just curious, what’s your reasoning behind switching to APA102? It might not be worth the extra expenditure if the WS2812 strips are still doing their job.
I’ve yet to see waterproofed APA102 strip below double the price of WS2812 strip.
My complaint with APA102 is not price (which, see below, seems roughly on par?), but rather that I can get a wider range of packagings (e.g. pixel nodes on a string) and densities (30/60/144) of WS2812B than APA102 – but I suspect that will change over time.
Here’s the quickie price check that I did:
-
144px/m WS2812B in silicone cover tube: $20/m http://www.aliexpress.com/store/product/144leds-m-WS2812B-5050-rgb-led-with-WS2811-IC-built-in-led-pixel-strip-DC5V-2m/701799_1827451697.html
-
144px/m APA102 in silicone cover tube: $19/m http://www.aliexpress.com/store/product/1m-DC5V-APA102-led-pixel-srip-IP33-144pcs-APA102-5050-LED-M-144pixels-WHITE-PCB-in/701799_32244460348.html
As always, I may have missed some detail, like the level of waterproofing, etc. But the last couple of batches of APA102s that I’ve bought seemed to be roughly comparable in price and features.
Where are you seeing much cheaper WS2812Bs, or much more expensive APA102s? We should all comparison-shop together…
Mostly on Ray Wu’s store (aka Shenzhen Rita), mainly because it’s what most people seem to recommend. Is there much/any difference between the manufacturers?
Sidenote: I’ve stopped trusting the IP ratings since that silicone tubing you linked is clearly better than IP33.