Originally Posted by
treebound
I picked up a small screamer type alarm a few months ago at a thrift shop for a few dollars, has a small pull cord to set it off kind of like a panic alarm and it is LOUD. I've thought of figuring out a way to rig it up to the bike where if the bike is moved then it would go off, problem is with wind and with other people putting bikes in a nearby rack location.
you can actually buy a bike alarm off of amazon... reviews said it did a pretty good job.