I have always wanted to make a tombstone popper so I finally took the plunge last year and set out to make one. I bought a wiper motor from http://www.frightprops.com along with their 5v5A power supply to give the motor a nice slow movement. I put the electronics inside of a water tight box to keep things dry since it rains so much here in Florida in October. Sadly the entire thing only lasted a few nights before the power supply over heated and melted. I bought another one only to find that the motor had been fried as well. I am not sure why this happened other than maybe I was asking too much from the motor and power supply to work for a few hours each night. I replaced the parts and decided to only put it on the big night and it lasted just fine that night.