Strident beeping alarm sound problem...finally solved !

I used to work in an office where the co-workers liked to prank each other. One of them had left a dead goldfish in my office and it took me a full day to find where the stink was coming from.

So I had an old smoke detector that I took apart and placed in a very hidden spot in his office. I powered it with a very weak 9v battery. It would "chirp" about every 3-5 minutes. Drove him crazy!