Pretty creative usage of the Atmega32! I wish I still had some of the pictures from a version I did with the Basic Stamp and Parallax Propeller. I started off sending frequencies to a piezo speaker like yours for the simulated 'success or failure' notifications, but it was suggested to me to use some of the 10 second recording modules that Radioshack sells. Turns out those worked great (When paired together with a pair of hacked together computer speakers). I ended up actually recording the sounds from Counterstrike into two of those modules and it turned out to work quite well. We didn't use an LCD like yours but I think that is a nice addition and could create some pretty interesting scenarios, given that the device is used properly and safely on privately owned land.
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