The radio shack tactile switches are probably too small and fragile for direct use on the ground, although they might be used in a paperclip wire pushrod type setup. The larger momentary switch probably can handle direct ground contact without breaking. It takes very little pressure to activate them (they now come in plastic bags instead of blister packs, so one can check the spring pressure in them and overall strength). For testing, one could make a simple rolled/glued round paper boot to mount them in and slip on the bottom of the hex leg. I like proving a concept is workable and useful before spending a lot of time and $$$ and find out otherwise.