I did this board for a regular customer who wanted to use an occupancy detector (like a cpOD or DCC-OD) to drive a bicolor LED indication on a control panel. The panel shows green while the track is vacant and goes to red when the track is occupied. Each board can support 6 3 lead (common anode) Red/Green LEDs. The board features a 74LS04 hex inverter, a pair of Single-in-line (SIP) resistors (one to pull the input up and the other to limit current through the common anode), pads for screw terminals for the LEDs and inputs from the detector and a screw terminal for +5 and Ground and a power on indicator LED to assist trouble shooting.

This works well when the bi-color LED is about the same brightness for both LEDs with the same current (about 7 mA in this case) but since about 20% of males have some degree of Red/Green color impairment, your mileage may vary, so check. If this design does not get equal brightness for you, try the "Advanced BiColor Occupancy Display" which adds another resistor pack to equalize the Red (usually the brighter color). Contact us if you'd like another variation!

This board is offered as a bare board, panel of 4, or as a bare board panel of 4 with the 4.7 K pull up SIP and 470 ohm current limiting SIP. Contact us if you want different values.

CAD Files and Documentation