74HC595 Shift Registers used as serial LED driver

The main method for driving large numbers of LEDs in SimVimX is the "series-parallel shift" method using latched shift registers. The easiest option is to buy multiple breakout boards with 74HC595 registers.

All you have to do is solder the LEDs with resistors to these boards.

You can use from 1 to 8 registers connected in series, that allows you to have up to 64 LEDs on ONE output pin.

• Connect the anode of each LED to the register output pin with a series current limiting resistor.
• All LED cathodes must be connected to the common GND bus.
• Two common SimVimX signal lines - D and L are connected to the related SER IN and L CLK (L_Clock) inputs on the first breakout board. The pin assigned as output for the serial LEDs in the plugin config tool should be connected to the CLK (Clock) input.

In the example below two pins #37 and #51 are used to control two register chains:

NOTE: Resistor values can range from 300 ohms to 1 kohms - you may want to start with a higher value to decide if the LED brightness meets your needs.

For example, when I built my Baron 58 panel (using the earlier ArdSim I/O interdace), all the LEDs in the audio panel had 1k ohm resistors, and the LEDs were more than bright enough:

As an option, you can buy 74HC595 register chips (about $1 for 10 ICs) and wire the LEDs directly to the register without PCB, or make your own custom printed board. Here is the connection diagram: