I really want to have it wireless. Right now I can reset the targets with the pull cord setup. But dealing with 50+ yards of pull cord is not fun. Same thing would happen if I had a wired switch.
I liked the blue tooth idea and setting up an app so that if I ever started selling these I would not have to provide a controller. All I would have to do is tell them download my app and they would be set and be able to use their phone which nearly every human on the planet now has which would save money and keep the cost down.
As far as protecting the Arduino and servo that would be simple to form a protective box and bolt the assembly on.