There is no better way to learn robotics and electronics than building and programming your own machines and robots. Electron Dust has shared a video that shows how you can use an Arduino Uno and Nano to build a ping pong ball bouncing machine that detects the location by using 4 microphones. As the developer explains:
The location is calculated from the time difference between mic pairs (one pair for each axis on the 2-dimensional plate). The noise from the ball hitting the plate is a very loud one. The Arduino checks the states as fast as possible, this allows for a reasonable accuracy. Another Arduino then uses this data to tilt the plate in such a way that the ball will not fall down.
You are going to need 4 stepping motors in addition to the above mentioned components to pull this off.
[HT]