Hi I'm new to this site and find it brilliant to use. I make all my own interfaces for FSX and P3Dv4.4 but now looking at X-Plan 11. I'm a Patron and have start to build my new interface and have a fully working radio prototype so I'm now looking at combining the MCP, lights, gear and other items all in one panel. I have started do the switches and testing the input MUX's and all work OK. However I'm having problems with the 595 using it as a LED driver for the annunciators. I have wired the register as: Ser_In goes to pin 28 (D), L_clock to pin 27 (L) and Clock to Arduino designated pin. I programed the Arduino pin and the LED driver for the LED and use 470ohm resistor to connect LED. It seems I must be doing something wrong as it doesn't work,can you help?