DMX Relay
DMX relay schematic

Part Value Farnell code
R1, R2 22R 934-2869
R3, R5, R7 - R9 470R 934-3245
R4, R6, R10 - R12 10K 934-2419
R13 10K SIL 8 935-6371
R14 10K SIL 6 935-6142
C1 - C3 100nF 750-992
C4, C5 22pF 746-990
D1 - D3 1N4004 956-5027
D4, D5 BZX85-C5V6 984-4252
D6 - D9 5mm LED 100-3213
XTL1 20Mhz HC49/4H 971-2879
TR1 - TR3 BC337-40 955-8675
IC1 PIC16F873A 976-1098
IC2 6N137 999-4866
IC3 MAX488 972-5598
IC4 NKE0505S 435-3195
RL1 - RL3 MR82-5USR 109-4027
CN1 - CN6 IMO 20.501M/3 963-2980
CN7 Molex KK 22-27-2061 973-1172
CN8 Molex KK 22-27-2031 973-1156
SW1 MCDA08 947-1561
SW2 MCDA04 947-1545
The colour of the LED is not important and so the Farnell part number supplied is that of a cheap Yellow LED, feel free to substitue this with any colour of your choice.

In addition you will also need the mateing plugs for CN7 & CN8. These are made from crimp housings 22-01-2065 (143-129) and 22-01-2035 (143-127) along with crimp connectors 08-50-0106 (101-2163).

If you only wish to use 1 relay then you will not need parts R8, R9, R11, R12, D2, D3, D7, D8, TR2, TR3, RL2, RL3 & CN3 - 6. In addition if you only need one set of relay terminals you can also dispense with CN1.

The DIP switches I picked have pin spacing the same as standard jumpers (511-833 & 972-8970), so if you want to save on the build cost then you can use jumpers instead.

You will also need a 5v supply and some suitable XLR connectors to complete the project.

Copyright © 2005 Ben Suffolk.