On Sun, 06 Dec 2009 19:06:17 -0600, Shaun wrote:

Other changes for more power and louder:

Change the 10 ohm resistor (R7) at the emitter of Q1 to a 3.3 ohms at 1
watt.
Change R6 to 180 ohms.
Change R5 to 470 ohms.
And for the piezo buzzer, use a piezo tweeter, you can get them off of
ebay.

Or just spring for a Sonalert and be done with it. ;-)

Cheers!
Rich