Perhaps you should use a low powered IR diode instead of the red.It would be little bit more dangerous to put together if you dont have a lot of experience, but would make for a more "stealthy" trip wire.
Re: FS: <600mW 445nm Dorcy Jr. PRICE REDUCED
If you cant sell the complete laser, I may be interested in buying the dorcy host, heatsink, and flexdrive.