Open Source Bits

DMX Controller for RGB NodesOkay.

Here they are.  Finally.  Field-tested, known good goodies.

Open Source T3 Controller Schematic [pdf]

Gerber Files (zipped)

Eagle Files (Authored in Eagle 5.10 Professional)

T3 Parts List (text file)

Design Notes:

  • Processor is a PIC 18F2610.  It has many pin-compatible brethren.
  • Top of the schematic contains a neat RS-485 receive section which is both optically and galvanically isolated from the rest of the world.  This conforms neatly to the official USITT spec, and this particular corner of the schematic has been field-proven by many hundreds of our other customers, over several years.
  • There’s a single LED for power, plus a second LED for status / user feedback.
  • This PIC contains EUSART and SPI peripherals on (conveniently) separate pins.  To drive 4 different string outputs, we use a flock of ‘AND’ gates to select and route the data to its proper destination.
  • Expected power source is 5V DC via a switching supply, rated at 3A per 42 nodes driven.  A fully loaded card requires about 12A.
  • There’s no polarity protection included on this board.  Caveat emptor!
  • Most parts are SMD.  Chips are SOIC, discretes are 0805.  Easy easy to hand solder.

I have 7 remaining bare PCBs based on this design.  An additional 15 are en route to mrpackethead (.nz) for distribution.  $10 each or 5 / $45.  If you want some, email ‘john AT response-box.com’ with the subject ‘Open Source PCB’

I do not plan to re-run these boards once current supply is depleted.

Source code is coming soon.  Check back!

16 Replies to “Open Source Bits”

  1. We would very much encourage someone to take this up as a co-op project or however, and share this design around! The gerbers are online, please download them, and send them to your favourite board house and get some printed for your self!

  2. Ah – forgot to discuss them. Thanks.

    We’ll bring in a few hundred of the 12″ pigtails. It’s probably 2 weeks out at this point.

  3. sounds good i just ordered 4 strings and extensions to play with. Is the crystal a 40Mhz? i think that is the only thing i could not find on the schematic. thanks you John and MPH

  4. how is the source code coming? and diagram of the pixel string connector pigtails? you have just been teasing to much here.

  5. For the components on these, was there a single parts supplier that you went through to get them? Or were the parts obtained from different places?

  6. I found everything at Digikey. Unfortunately, I don’t have a list of exact part numbers nearby. Resistors should be +/- 5%, capacitors should be rated at 10% or better tolerance, 10+ volts.

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