usbdmx : The bus powered usb dmx interface : Schematic The schematic above is marked as revisino 1.2, but it is identical to the 1.3 revision with 1 excpetion. The is a 100R resistor on the RD & WR lines between IC2 & IC1. I will update the schematic as soon as I get a chance to reflect this. The following table lists all the parts you need to DIY USB DMX Interface for under 10$ - Steven B. May 11, 2013DIY USB DMX Interface for under $10. The DMX protocol is the same as the RS485 protocol, so we can use any RS485 USB converter to control DMX devices. DMX controllers are usually not that cheap, using this guide, you save money for possibly a hardware midi controller for your lighting software.