On Tue, 09 Oct 2007 18:06:24 -0400, Brian Lawson
wrote:

On Mon, 08 Oct 2007 22:05:42 -0500, Don Foreman
wrote:


Mice and other small rodents are repelled by frequencies in the region
of 25KHz to 35KHz. It needs to be fairly intense (93 dB or better)
and it's best if it is intermittent and frequency-modulated at a low
rate. I used cheap Motorola piezo tweeters, sometimes as little as
$3.95 each.

Tried in two northwoods cabins, worked in both. Man, did they come
outta the woodwork and scurry for the woods when I first turned that
sucker on upon arrival after being away for a while.


Hey Don,

WOW!! 93 db. What will that do to "other" local inhabitants, like
the neighbourhood dogs and cats?

Probably not. The larger the critter the lower the highest frequency
heard. I think dogs 'n cats are only good to about 25 KHz or so.
Also, it'd have to be highly directional to have much effect beyond 50
feet or so. And anyway, who cares if it repels stray dogs 'n cats?

And will that freq & audio level attract other species, like crickets
or something?

It is said to repel cockroaches, but I can't vouch for that. The
cabin was not festooned with horny bats.