I ordered some books from Amazon, most of them being Cy Tymony’s “Sneaky Uses for Everyday Things” series. So far I’ve received three books, and one is three times thicker than the others. It turned out that this book is really three books under the same cover. It’s ISBN: 978-0-7407-8424-8. From what I’ve read, it seems that there is some duplication between books.
Everything is preceded by “sneaky”, for example sneaky radio receiver, sneaky compass, etc. I’ll not use that term.
The main piece of equipment for many projects is a cassette tape recorder that has been se to record and pause. This turns it into a monitor so that anything plugged into the microphone jack is amplified and also sent to the earphone jack. The author uses this to make a ‘radio receiver’ that really doesn’t receive radio waves. The output of a small radio is connected to a large loop of wire that acts to make a magnetic field in the room. This recorder then picks up the magnetic field, but this is not really receiving radio waves.
In another communications device, the radio is used to modulate the light from a LED and batteries, which sends out a light beam. This is received by a photocell that is plugged into the microphone jack of the recorder and amplified to drive an earphone.
Another project is a microphone. This is made from pencil leads that are mounted inside of a cardboard box that originally held paper clips. A battery powers it, and an earphone is the used to transform the electric signal back to audio.
In addition to the projects, there is a section on “sneaky survival techniques.”