Why not try a PIEZO Electric disc. Its innexpensive and verry sensitive
if you mount it firmly on the surface. You can salvage the disk from a
commercial pizzo buzzer ( The large the better ) or buy just the plain
disk ( available from some distributor ).Take a look ay Shyogo Web
site(http://www.shogyo.com/), the have a huge variety of piezo.

   Eric

>From owner-piclist@mitvma.mit.edu Thu Jul  9 11:07:50 1998
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>Message-ID:  <19980709170637.21873.rocketmail@send1a.yahoomail.com>
>Date:         Thu, 9 Jul 1998 10:06:37 -0700
>Reply-To:     pic microcontroller discussion list
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>From:         Rock Thompson <rock_t@YAHOO.COM>
>Subject:      Bouncing Ball Detector
>To:           PICLIST@MITVMA.MIT.EDU
>
>In an effort to further the athleticism of my children, so they can
>someday be filthy rich and support their kindly old father, I am
>building a wooden target for them to throw a ball at.
>
>I want to count the number of times the ball hits the target.  A PIC
>will count the number of hits and handle an LED display.  But I'm
>hoping for suggestions on how to detect the hits.  Two things come to
>mind: An accelerometer responding to the vibration of a hit, or a
>microphone that picks up the sound of a hit.
>
>Any further ideas or comments?
>
>Thanks, Rock
>
>
>
>
>______
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