About a week ago we discovered we have mice in the eaves, a situation SWMBO asked me to remedy in my own time, or at least that's how I chose to interpret her hour of screaming hysterics...
So, following on from a design for a mouse trap Ste and I made about twenty years ago, which caught a dozen mice in its first four hours of operation, I hacked together a transparent box with some bait, an infra-red beam to detect the mouse and a solenoid operated trap door to catch it. This was then placed in a likely spot and an infra-red video camera rigged up to watch the mice being caught.
About an hour later the first customer turns up. After a cautious sniff around the outside it stuck its head and shoulders into the box and rooted about, not going far enough in to break the beam. Fair enough, perhaps mice have grown more cunning in the last twenty years... Nil desperandum - give them a chance to get used to it.
A bit later another mouse appears and goes through the same process... Perhaps they don't like plastic boxes?
Then one turns up and gets inside the box - I sit poised - surely this is it? But no, somehow the bloody thing doesn't trip the trap, and leaves. Bastard, I'll get it next time... But no, it's back, and this time it brings a friend. To cut a long story short they explore the box, they party on down on the bait, they jump about, have sex, snooze a little, and at no point does the bloody trap door close. After a bit they get bored waiting for something to happen and wander off, presumably giving the place a bad review.
Only then does it occur to me that a mouse trap that relies on the mice breaking an infra-red beak in a transparent box is probably not the best thing to watch using an infra-red camera that has about a dozen high-intensity infra-red LEDs built in as illumination... Doh!
Got 'em when they came back an while later - amazing the difference a bit of cardboard around the camera makes...