Here’s code and designs for making a simple tire into a touch sensitive input that can really be smashed around!
Sample Cap Touch Code here. Library is embedded in the code, so just upload and go!
https://github.com/quitmeyer/WorkshopFieldCode/tree/master/Plant%20Touch
Just connect something metal between Analog Port A0 on your Arduino to the metal insides of the tire (preferably a chain or something that gives you some distance!)