I recently decided to have a go at building a custom controller for ETS2 so it feels more natural and controlled to look around, paticularly at junctions rather than user the mouse or buy an eye tracker.
The prototype has exceeded my expectations and I'm constantly using it while playing, even though it's setup on a breadboard and 3D printed controller. It works by twisting and tilting a head to trigger the look left / right actions, then recenter and adds a virtual click to recenter in game.
I've added some additional buttons for other games, such as visor tareoffs etc. What other functions do you think I could build out that would be useful, and do you think it would be useful if I was to productionise it, or make the instructions available for others?