PIC18F Based 6 Channel DMX Transmitter

Based on AN1076 - "Using a PIC® Microcontroller for DMX512 Communication". Modified and added to Microchip's code to use 6 AdC Channels for 6 channels of DMX data and the ability to offset its starting address via a 9-position DIP switch.

Designed to demonstrate a simple DMX transmitter and to test DMX Controlled lights without having to adjust their address or change anything in a prepared show if using DMX Software and USB DMX device.

It is written in Assembly and utilizes a PIC18F24J10. A bit odd as it's voltage input is 3.3v and it requires a low ESR capacitor to ground on one of its pins. I am sure the code could be modified to work on any 18F PIC with a EUSART. 

There is no PCB layout, it is easy enough to construct point to point on perfboard.

Please Take a look at AN1076  From Microchip and the PIC18F24J10 Datasheet.

I apologize about my images as my camera decided to crap out with this and another project worth of images on it, so I did my best to recover and recreate them.

*UPDATE:
V2 - Updated the schematic to show the potentiometer hookup. 
V3 - PIC Transmit pin was hooked up to the wrong pin on the SN75176, fixed, should be pin 16 on the PIC connected to pin 4 on the transceiver. A pretty big mistake, sorry to anyone that got screwed up by it.

DISCLAIMER: Not responsible for any damage or injuries resulting from this instructable. Damage to DMX Devices is possible if this transmitter is not built correctly.

Step 1 Supplies

Parts:  (all ICs are DIP spacing)
- 18F24J10
- SN75176A - RS-485 differential bus transceiver
- 28 pin socket
- 8 pin socket
- 10 position DIP Switch
- 3.3v linear regulator, TO-220
- 16 mhz Crystal Oscillator - I used ECS-2200BX-160
- 8 pin socket
- 28 pin socket
- 6x slide or dial Potentiometers
- Female XLR, i use panel mount
- Male XLR, not really needed
- 2x 10 1/4w resistor, R3 & R5
- 100 ohm 1/4w resistor, R2
- 120 ohm 1/4w resistor, R4
- 10kohm 1/4w resistor, R1
- 10uF low ESR cap, less than 5 ohm, but most caps can still work,C1
- 2x 1uF electrolytic capacitor, C3 & C4
- 0.1uF disc capacitor, C2
- Perfboard
- Solid strand wire
- 5v @ 500ma PSU
- DC Power Jack, I used a 2.1mm that matched my 5v power supply. Buy PSU with Matching Jack
-Enclosure, or parts to build one.

Tools:
- Solder
- Soldering Iron
- Pliars
- Diagnal Cutter

Comments

[SimonTunes]

Sorry, how can I connect the male XLR port?
Anyway, this is a very interesting project! Can I buy a KIT with the components? ;)
Thanks!
Sorry for my bad english.. I'm Italian! :D

[asmodi]

Project is cool but Can you use USB connection with this project?

[PS118]

Can't really read the schematic. Could you please add that and possibly the firmware as downloads?

Thanks. :)

[ChromationSystems]

Its all in the ZIP file in step one, eagle files, schematic, source code, HEX files

[PS118]

Cool, thanks!

[joejoerowley]

Pretty badass. What's the plan for this guy? Hooking it up to an ion or something? haha