XPNDR - alesskerbinek/FlightSimPanel Wiki

The purpose of this unit is to simulate transponders like:

Requirements:

No Type Item Function
1x input Rotary Encoder with push button Squawk select
6x input Pushbuttons OFF, SBY, ON, ALT, IDENT, VFR
1x output 4 Digit 7-segment display Active Squawk
1x output 3 Digit 7-segment display Current mode

Instead of a rotary encoder we could add 10 numeric buttons, but that would require additional PCB.