Has anyone used these?:
http://www.seeedstudio.com/depot/WS2812B-Digital-RGB-LED-FlexiStrip-144-LED-1-Meter-p-1868.html
And, if so, would there be an issue with a 5M strip? (720 LEDS)
I gather that it would require 5x8.64A (so a 50A power supply) - but would there be any other considerations for driving a single 5M strip from a micro? (doesnt need to be NETMF if timing is an issue)
Yes I use them.
The A figure is for all LED’s being on full white as each LED is 3x 20ma
Simple to drive 240 using NETMF and cant see any issue with driving 720
@ mtylerjr - Main issue is power. The more LEDs you’re driving, the more power you’ll need. For more than a meter, it’s best to use a separate, high-amp power supply. The Adafruit NeoPixel uberguide has great advice on this:
[url]The Magic of NeoPixels | Adafruit NeoPixel Überguide | Adafruit Learning System
Even though you’ll be running these with NETMF, you’ll have good results if you follow the power advice there.
If you find that the LEDs at one end of the strip are looking dim, you’ll need to add more power somewhere in the middle of the strip.
The WS2811 library here should work fine:
[url]https://www.ghielectronics.com/community/codeshare/entry/977[/url]
Enjoy!
IIRC, the only diff between the WS2811 and the WS2812 is that the latter have the driver chip in the same package as the LED.
How likely is that? Can I not just use a bigger power supply at the one end?
As I understand it, no. You can certainly use something that can supply more amps, but even that won’t overcome the issues with powering a really long strip. Realistically, you should be fine with 5m. I’ve played with a couple strips of that length, and as long as I used a beefy supply (I’ve used both these from Adafruit:
http://www.adafruit.com/products/658
As well as my own home-built frankenPSU made from an old PC power supply.
Biggest thing is to avoid powering with more volts than the strip is rated for. Digital RGB LEDs are very touchy about that (part of why Adafruit recommends the sizeable cap in line with the power supply, to protect against spikes). I’ve fried a few LEDs when I didn’t look closely enough and plugged in my 12V power supply on a strip rated for 5V. I very quickly used my label maker to put LARGE labels on all those supplies.