One of the biggest questions when beginning to build any home cockpit component it how to interface the components with your chosen flight sim.
There are many ways to interface the components with your computer, but by far the easiest way is to use an Arduino Board.
We at SimSwitch use MobiFlight for all interfacing with MSFS2020 and Xplane. We find it very simple to use and it has a large preset library to select from, best of all, its free to download and use as of the time of writing.
There is a range of other options, however some can get prohibitively expensive to purchase and tend to cater for specific airframes, for the remainder of this guide we will be focusing on MobiFlight.
After downloading and installing MobiFlight, when you open MobiFlight for the first time, you will be required to flash the MobiFlight firmware onto your Arduino compatible board. Please note, all our boards have been throughly tested to ensure compatibility with MobiFlight as some unsupported boards can work but can behave strangely.
After flashing the firmware, you will need to add the input/output device you have connected, simply click add device, select the appropriate device and assign it the pin number you have wired it to on the board. We find DuPont ribbon style cables with male ends and a bread board can be very helpful when beginning to prototype, as if it doesn't work, the wires can be moved without much fuss. Once the device is added, select upload in the lower left corner to update the firmware.
We now have a controller board that can communicate with your PC.
From here, we select what we want the device to do, please see the video below on how to flash the Arduino compatible board, add a device (in this case and LED output and toggle switch input), and assign it to an in game command.