That's simple what ever you want to explode, hook into the speaker wires. With out the speaker those two wires can go to a relay to trigger anything. These are the same thing Radio Shack sold 10 years ago for $20. A personal burglar alarm only with a remote. I would use in the bread box to protect my twinkies and scare the crap out of Vampirella as she tried to get them. usually a 9 volt system. Even if it is only 3 vollts it can do anything.
Another fabulous post from the U.S.Department of Wild Imaginings, now in spectaclar stereo, sponsored by the Adhesives and Sealants Council, suggesting ways to stick things together since the 1800s. Not fabulous in a gay way. Your results may vary. Illinois residents add 8% sales tax. These posts have been made by professional post makers, do not try this type of posting on your own without extensive training, lovely assistants and a trusty clown horn.