Head on down to McDonalds, order the adult happy meal with the pedometer. It comes free with the meal, while supplies last. Counter will go to 99,999 counts and can be reset with the push of a button. It uses simple mechanical contact to close the circuit. There's a weighted arm held off the contact with a hair thin spring. Would be easy to rig something to trip this mechanically, or simply wire in your own switch.
Jon