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ZeroPoint
08-31-2013, 04:51 PM
Good morning! My name is Luke and while my LED passion mainly revolves around lasers it has quickly grown to include their incoherent counterparts as well. Anyway, after deciding to take on a few addressable led projects I have stumbled upon a couple items; 1) is the Teensy 3.0 which I will surely be using for my LED screen and 2) is the ws2811 IC for LED control. My question as of right now is directed toward anyone that is familiar with the LEDs with integrated ws2811 chips that are selling for $.14/each on Aliexpress (here - http://www.aliexpress.com/store/product/WS2812-LED-5050-SMD-RGB-LED-with-embedded-WS2811-IC-1000pcs-bag/701799_825160465.html). I understand that this is not a plug-n-play strip but I am unsure of what exactly is not included. Clearly it includes the LEDs and the 2811 for each LED but what else is needed to get them illuminated besides a significant amount of wires and soldering? Do I need to buy resistors and capacitors to include in the circuits or are they integrated as well and I just need to connect the appropriate pins to each other and go? I know I will have plenty of questions about the Teensy when I get to that point but I need the LEDs first :D Anyway, Thanks for any light you can shed on this (coherent or not) and I can't wait to explore this forum some more!

BTW, if anyone here is also a laser freak I go by ZeroPoint on www.Photonlexicon.com as well (maybe I'm not the only one to frequent both forums?)

Thanks again,
Luke

Mike Prevette
10-16-2013, 11:57 PM
Where to start.

So you linked to a roll of bare ws2812 LEDS. These are 5050 (5mmx5mm) size packages they are tiny and hard to hand solder. I have hand soldered hundreds and it is a MASSIVE pain even with a jig. If for some reason you really need bare LEDS then be sure to get the new WS2812B version. They have 2 less pins (4 instead of 6) only one VCC pin and reverse polarity protection, as well as some improved performance. If you are planning on wiring them in series of any length you will want decoupling capacitors for each chip.

I highly HIGHLY recommend purchasing a pre-assembled strip to start with. either the 60led/Meter or 144led/meter strip. Most of them these days will have the WS2812B chip, they all have SMD capacitors for each led, and BONUS the soldering is done for you!

Now if a strip isn't what you are after I still recommend buying it in strip form. The flexible PCB they come on is marked every LED with a cut line and has solder pads for each LED. It is SO MUCH EASIER to cut the individual LEDs off and then solder wires to the pads on the pcb than it is to solder to the chip itself by hand.

Adafruit is a great retailer that has all these strips (under the faux brand name NEOPIXEL) for a reasonable price (only a few bucks more than ordering from Ali once shipping and customs is included)

Headroom
10-17-2013, 12:43 AM
Depending on what you want to do with the LEDs in your project, http://www.kickstarter.com/projects/311408456/rgb-123-led-matrices these panels with 5050 LEDs may also be a nice option.

PaulStoffregen
10-17-2013, 07:36 AM
If you buy Ryan's RGB-123 panels, please be aware the signal is serpentine routed on the 8x8 and 16x16 sizes. OctoWS2811 does not currently support that. Perhaps Ryan or someone else will contribute code to re-arrange the pixels, either on the PC side or on the Teensy3 side? I'm not planning to invest engineering time to support that configuration.

Sadly, I spent about half an hour on the phone with Ryan the day before his Kickstarter ended. He understood the issues, but decided not to modify his PCB design, even merely adding extra pads and locations to cut traces. I didn't get the impression Ryan has much software skill, but hopefully he'll find someone willing to do this work. I'm willing to accept well designed and tested patches if anyone does it.

Headroom
10-17-2013, 10:36 AM
Paul, I was not aware of that. Thanks for bringing it to our attention!