Manual treadmill to PC input with arduino - now adding ducking maneuver

I created a manual treadmill where I could walk/run in PC games. It's pretty awesome. I mostly did it to lose weight. Here are some time progression videos:

This is the first video I ever made about it:

I then made a follow up video

And this is basically how it looks like/works now:

I'm not here to show off. Okay, maybe just a little bit :slight_smile: , fun, right? But it's not that complicated after all to do, just a black&white line tracking sensor and arduino micro, some buttons and an LCD. Piece of cake. (Although I did find out that the I2C of the LCD slows down the arduino micro, so now I need to press a switch in order to adjust speed parameters and then turn off that switch while I run...)

ANYWAY,

I want to create a game in Unity specifically for my treadmill and give the runner more options to avoid objects while they're running (and create more challenges). So I want to add a sensor for ducking (in my last clip I use a Joystick for ducking). Which sensors would you suggest to use for that? Or rather, how to go about it?

And yes I know VR already has a built-in solution for what I'm asking, but it's not comfortable to run with a VR headset on (+it's extremely dangerous without something that straps you to the treadmill - I tried walking with VR once without strapping myself and almost injured myself). I don't really need hands control or full body tracking, I just want to recognize ducking.