In ,
wrote:

For several years now, we have mice/squirrels making noises
in the attic and nowadays in crawlspace.

I read about strobelights and wonder if anyone out there has tried
this? Or other devices to repel them humanely?

Does the strobe light require to be on the whole time? And can it be
controlled remotely, i.e. shut off prior to going to attic so as to
not damage human eyes.

Also, is there any danger that rats/squirrel may have trouble exitting
property with these lights?

Finally, is there anything else on the market that can repel that does
not involve putting chemicals of any kind?

Effectiveness of strobelights - I don't know, though I suspect they will
repel nocturnal varmints.

Need to keep running - I would say yes.

Safety of strobelights to humand and property:

The eye hazard is very minimal - I looked into the darn things too
bleeping much, since I used to build such things. Avoid staring into one
for more than several seconds, and I think you will toast your eyeballs
even less than I haven't.
(Warranty: If you toast your eyeballs with my advice, I refund what you
paid me for it and no more.)

I wrote the following web page:

http://members.misty.com/don/xesafe.html

Eye hazards are relevant pretty much to strobe beasts more serious than
usual "party strobes".

Hazard to animals' eyes - I would say similar, fairly certainly zero
actual damage if the strobe repels the varmints rather than causes them to
get entranced and stare into the darn thing at close range.

Other possible hazards - I would worry that all too many strobes of
reasonable to low price are cheap units made by low bid manufacturers and
that they may have passed UL testing by the skins of their teeth. I am
very leery about letting much of anything electric other than
refrigerators and climate control equipment do a lot of running in rooms
that are usually unoccupied.
For one thing, the energy storage capacitor is unlikely to outlive you,
and it could kick the bucket in some spectacular way or another.
For another thing, summer heat in attics may cause electronic products
to fail with components going short-circuit or partially-short-circuit,
or cause plastic parts to melt out of shape.
I see too many strobes that I would only run in an attic if placed in a
manner that makes it acceptable for them to catch fire or spit sparks of
molten metal a couple feet - may be hard to do. Otherwise, if you can
find one that is both well-fused and made with non-combustible structural
materials and will contain any components inside blowing up and spewing
sparks, it may be reasonably safe for prolonged unsupervised operation in
an attic.

(For that matter, I have seen a couple window fan motors catch fire -
with actual flames - once the motors get gunked up inside from dust and
get bogged down. That was back in the early and mid 1970's, when most
electrical and electronic goods in USA were made in USA!)

Alternatives:

The main electronic one I am aware of is the ultrasonic pest repeller.
I have seen a fair amount of negative press about actual effectiveness.

Probably better to seal up / repair whatever the varmints are getting in
through.

- Don Klipstein , )