Office Lights

How many projects is it okay to start without finishing at least one? It seems I’m determined to find out. I’m currently in the process of finishing a room in my basement which will become my new office/hackerspace. Naturally, I incorporated copious amounts of LEDs into the design. I picked up a couple of reels of strip lights from ebay.

LED Strip Light

LED Strip Light

The LEDs included an IR remote which allows you to jump to predefined colors, or select a couple of predefined animations. Cool, but not that cool, so I got to work. These strips are able to be cut every few inches without damaging the rest of the chain which creates the potential for several strips, each with their own color. Upon inspection, I found that each section had 4 copper pads labeled Red, Green, Blue, and Common. Could they have made it any easier? I quickly determined that the LEDs were common anode so the TLC5940 LED driver which I seem to have an attachment to is a perfect match. I had a demo up and running in under an hour. (I promise that someday I’ll make a project that doesn’t include this chip… someday.)

With the proof of concept complete, I cut the strip light into smaller strips and laid them out where they will be installed, I quickly realized that it would be a much better use of wire to have a few TLCs spread out at strategic points instead of having a singular control box with 87 bazillion wires travelling extended lengths to all of the various mini LED strips. A TLC5940 breakout board would have done the trick nicely, but I already had several TLCs collecting dust so I made my own.

TLC5940 Breakout Board

TLC5940 Breakout Board

The mess of solder underneath won’t win any competitions, but when I plugged it all in, the test LED lit up, so I was happy. I’ve got another two or three to make, so perhaps my technique will improve.

I’m also interested in cracking open the original control box at some point down the road. Perhaps I can reuse/improve the IR remote as a control interface. Well, that’s all for now. We’ll see you next time when I start another project finish something.

4 thoughts on “Office Lights

  1. omar

    How did you get the 24 key remote led to work I have one and it does not work please email me

  2. heathbar

    The LED strip came with the remote and the sensor and just worked out of the box.

  3. Chris

    Hey! I’m trying to do exactly the same. how long is your RGB Wire which you drive with the TLC? I have 4 RGB Stripes with each 3 Segments, every colour is using 60mA, they all toghether burned my TLC cuz energy dissaption. Do you have the same problem? How you solved it?

    Greetings, from Bremen!
    Chris

    • heathbar

      I ended up putting the TLCs close together because I ran into issues when they were spread out. If you’re going to have long runs between the TLCs, you need to make sure that they are all very well grounded. Low voltage DC currents don’t do well over distances, which is why I ended up placing them close together and used longer wires to each LED strip.

      You can draw a maximum of 120mA per channel on the TLCs, however, as you found out, you cannot draw that much power on all channels simultaneously. The reason is that you will exceed the TLC’s power dissipation rating. There’s some discussion here (http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1220278222) about how to calculate your power dissipation. I’m actually still trying to figure some of this out because I have a few 3-foot RGB strips that I’d like to control with a TLC, but each of the red, green & blue channels on my LED strip draw so much current that they almost each need their own TLC. I’ll be sure to post my findings if/when I finish this project.

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