USB DMX Interface

This is yet another circuit for producing DMX output for entertainment lighting from a PC. Designed with flexibility in mind, a range of circuit configurations are possible. Opting for no isolation requires just a PIC microcontroller and a standard RS-485 driver, with an approximate total cost of less than £10, – while for a few pounds more, full galvanic isolation can be implemented to provide protection for the PC, or a keypad added to allow for standalone operation. With the addition of I²C memory, scenes and test sequences can be programmed with a PC and stored for playback later.

Features & Uses

• Hi Speed USB link, host powered
• Provides realtime, buffered, galvanically isolated, DMX output
• PC interface for virtual console application
• Riggers remote
• Testing/servicing of units
• Simple, standalone scene playback
• Programmable scene memory
• PC DMX output protocol compatible with existing interface, and thus all major OSs
• DIL components simple to construct with just basic tools/electronics knowledge

Circuit

Further documentation will be added later, in the meantime, a rough schematic is provided.

OpenLX USB DMX interface

Resources

PCB layout, bill of materials and downloadable firmware to follow

Links

Ben Suffolk's USB interface
Development of OpenLX companion software

To-do list

In the future it is hoped to add the following features

• DMX reception
• USB battery charging
• In-the-field firmware updates
• Possible incorporation into USB wing project