I am the one working on the ping pong table and I have come to a halt. jason721 helped me by showing me inductive technology to try I am at a standstill at trying to figure it out. I don't have much money for any kits to learn how to use it and I have tried looking at videos and reading. I have 2 main parameters in trying to recognise the ball getting hit on the table and they are the balls heat and size. i have picked these 2 because then people cant cheat by using their hands or the paddle. any help on giving me suggestions for a type of sensor would be greatly appreciated or to tell me that i am going in the completely wrong direction is ok too. thank you.