look at tennis ball machines. Most use air...

wrote in message
oups.com...
The dog would play fetch all day if us humans
didn't get tired of throwing it.

I want to build an automatic thrower. Train
the dog to drop the ball in a 'hopper', the
machine waits 10 seconds, beeps, and throws
the ball.

I am looking for ideas on the mechanical
throwing mechanism.

Rich