Art and Technology are Friends

Aurora 18 prototype

New project using RGB/tricolor LEDs. Tricolor means triple the number of LEDs to control – more load on the processor. I decided to move up to 16 bit PIC, 24F series for the increased processing speed (MIPS) and memory. 16 MIPS and 4 KB of RAM and still had to resort to multiplexing RGB channels. 18 LEDs color/brightness individually controlled in gamma-corrected 8 bit levels (equivalent to about 14 bit linear PWM).

Countless software tweaks later I’m getting 200 Hz refresh rate. Hard to tell from the video, but the fades are truly smooth.

The circuit is quite simple. Besides the PIC and the LEDs, 6 transistors and a few resistors & caps. No current driver ICs or shift-registers.

Here’s the schematic for anyone interested. LED to PIC connections can be rearranged – mine was dictated by the PCB layout. I wanted to route the I/O pins to the nearest LED on the PCB (being fabricated right now – stay tuned for the update).

Aurora 18 Schematic

Aurora 18 Schematic

6 Responses

  1. Aki

    Is it possible to program the PIC with this?

    If not, if you would be willing to at least give all of your amazed friends out there a copy of the files (HEX files for flashing the chips, Gerber files to get the boards made and a BOM with sources to purchase) we could attempt to make it. The Indestructables as a tutorial is enough so you have already done all of the work. I am a surgeon and have loupes and a steady hand. Surface mount components are a non-issue for me and although time consuming, I think I could do the whole thing by hand without a heating plate.

    If you have the time, I am sure you can make a profit on selling partial kits with just the programmed PIC and PCBs. If you send a bulk order for PCB fabrication, the price can be small. You could post something and first see how many people are interested just to get an idea. I bet you would be very surprised by the responses. If not, then we are all stuck with the vicarious thrill of mesmerized watching on your beautiful website. Very nice work indeed!


    June 18, 2011 at 9:43 am

    • Gary B

      I agree with Dan. I am sure many many people such as myself would LOVE of have one of the Auroras. If you could come up with a price for the Aurora in kit form and post the amount, then you could get a better idea of how many are then wanted. I know I would pay into the mid hundreds for one. Please think about it. You have something that NO one else has, so yes, it will sell. Keep us posted.

      Gary B

      June 25, 2011 at 10:12 pm

  2. Dan Kuriloff

    Is there a kit available or finished PCB to build this marvel?



    June 16, 2011 at 10:14 am

    • It is under consideration. I will let you know when that happens.


      June 16, 2011 at 11:54 am

  3. I would like to make an LED “color organ” (these wre popular in the late 60′s early 70′s) that responds both to the amplitude and frequency of the input, usually from a music source. Usually the musical frequencies were split into 3 channels roughly low, medium and high frequency ranges. The effect was great as the rainbow colors followed not only the beat but the pitch of the music. Some really interesting color effects could be had. I would liketo find a way to adapt one one the current LED color bars available into a color organ. Do you have any suggestions?

    Gary D.

    March 11, 2011 at 11:00 am

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