Shop OBEX P1 Docs P2 Docs Learn Events
RGB LED Strips — Parallax Forums

RGB LED Strips

ajwardajward Posts: 1,130
edited 2013-11-06 14:47 in General Discussion
Has anyone hacked, modded or tweaked something like this?
http://www.ebay.com/itm/Hot-Sale-5M-300LEDs-RGB-3528-LED-Light-Strip-home-Decorate-44Key-IR-remote-DC12V-/281200040216?pt=Motors_Car_Truck_Parts_Accessories&vxp=mtr&hash=item4178d41918

I got a set for cheap and thought adding a Stamp or Prop might make for some interesting lighting effects.

Any thoughts are appreciated. Thanks...

Amanda

Comments

  • prof_brainoprof_braino Posts: 4,313
    edited 2013-11-04 13:06
    all i did was mount a 5 m strip above the kitchen cabinets for indirect lighting.
    the parts at the far end were dimmer and had different colors.
    so i ran a heavy gauge wire from GND at the controller to the far end.
    now all the LEDs are more evenly lit and the colors are consistent, at least to my eyes

    also, i didnt mount the strips, i didnt trust the sticky backing, and several seem to be lifting off the strip, individual LEDs flicker on occassion.

    thats all i got
  • skylightskylight Posts: 1,915
    edited 2013-11-04 13:54
    We've found at work that long strips do fade at the far end but if the supply is connected at both ends this tends to sort the problem out.
  • dmagnusdmagnus Posts: 271
    edited 2013-11-04 15:32
    I've got one laying on the bench in the shop. Haven't had time to play with it other than to try out the remote (kinda flaky) and see that all the LEDs light up.
  • TymkrsTymkrs Posts: 539
    edited 2013-11-05 17:33
    This is, I believe, the closest we got to it: http://tymkrs.tumblr.com/post/15403162286/separate-power-regulator-hooking-up-the-rgb-led Roy wrote a led driver which I think he put on the OBEX at some point, but it makes the LEDs light up!
    ajward wrote: »
    Has anyone hacked, modded or tweaked something like this?
    http://www.ebay.com/itm/Hot-Sale-5M-300LEDs-RGB-3528-LED-Light-Strip-home-Decorate-44Key-IR-remote-DC12V-/281200040216?pt=Motors_Car_Truck_Parts_Accessories&vxp=mtr&hash=item4178d41918

    I got a set for cheap and thought adding a Stamp or Prop might make for some interesting lighting effects.

    Any thoughts are appreciated. Thanks...

    Amanda
  • Duane DegnDuane Degn Posts: 10,588
    edited 2013-11-05 18:01
    Tymkrs wrote: »
    This is, I believe, the closest we got to it: http://tymkrs.tumblr.com/post/15403162286/separate-power-regulator-hooking-up-the-rgb-led Roy wrote a led driver which I think he put on the OBEX at some point, but it makes the LEDs light up!

    Those look like WS2801 LEDs. The WS2801 have the all three colors in a single LED and are individually addressable (very cool). The LEDs Amanda has have separate LEDs. I'm not sure if Amanda's LEDs are individually addressable or not. I'm pretty sure Amanda's LEDs are not controlled the same way and the WS2801 LEDs are controlled.

    The WS2801 LEDs are really cool. I've used them in a couple projects myself.

    Edit: According to the Roy's code those are WS2801 LEDs. IMO, it would be a good idea to include what kind of LEDs they are on your Tymkrs Tumbler post. There are a variety of individually addressable RGB LEDs each with their own communication protocol.
  • prof_brainoprof_braino Posts: 4,313
    edited 2013-11-06 13:48
    OK, now you got me thinking. And my head hurts!

    How would one go about taking a 5m roll of RGB LED that are NOT individually addressable (just 4 conductors, R, G, B, and ground) and MAKE it individually addressable?

    How would one go about taking a 5m roll of monochrome LED that are NOT individually addressable (just 2 conductors, power and ground) and MAKE it individually addressable?

    For example, to connect power at both ends, all we need to do is add another conductor of the same length. To make them individually addressable do we have to add another conductor for each LED?
  • GadgetmanGadgetman Posts: 2,436
    edited 2013-11-06 14:25
    Well, you could always add a DS2405 1-Wire switch or similar for each and every LED...
    (The DS2405 can't sink more than 4mA, though)
    http://www.maximintegrated.com/datasheet/index.mvp/id/2906
  • Duane DegnDuane Degn Posts: 10,588
    edited 2013-11-06 14:25
    prof_braino wrote: »
    OK, now you got me thinking. And my head hurts!

    How would one go about taking a 5m roll of RGB LED that are NOT individually addressable (just 4 conductors, R, G, B, and ground) and MAKE it individually addressable?

    The real answer is you don't. You go and buy an individually addressable strand. But if you wanted to to it the hard way you would add a WS2801 chip to each set of RGB LEDs.

    Another bad alternative is to run a cathode wire from each LED and control the cathodes with shift registers.
    prof_braino wrote: »

    How would one go about taking a 5m roll of monochrome LED that are NOT individually addressable (just 2 conductors, power and ground) and MAKE it individually addressable?

    This time it's shift registers again or some other LED control chip.
    prof_braino wrote: »

    For example, to connect power at both ends, all we need to do is add another conductor of the same length. To make them individually addressable do we have to add another conductor for each LED?

    Without adding some control chip like the WS2801, you basically need to add another conductor for each LED. It would be possible to multiplex the LEDs but they would still need another wire for each LED.

    I've used three different kinds of individually addressable RGB. The WS2801 stand like those used in my previously linked to mood enhancing LEDs, Some Christmas LEDs I purchased at Costco and the WS2812 LEDs. These three types all have data sent from one end of a data cable and the data gets daisy chained on to the rest of the LEDs.

    The problem with this sort of protocol is the communication time can start to take a while when when there are a bunch of LEDs. For an array of LEDs I think shift registers are a better alternative. I linked to a couple of my LED array projects earlier in this post.
  • GadgetmanGadgetman Posts: 2,436
    edited 2013-11-06 14:47
    The DS2405 should be able to function without adding a line to the system.
    (The signal is transmitted on the Power line. That's what is so nice about 1-wire systems.)
Sign In or Register to comment.