We posted this a long time ago, but it’s still a great project Liane writes –
While searching for a simple FM radio receiver schematic, I came across this incredibly basic radio made from magnet wire, a hydrogen peroxide bottle, a germanium diode and a telephone handset. It’s simple enough for a child to build and it doesn’t even require a battery to work! Scroll down for great pictures and easy directions for making Baby’s First Radio, as I like to call it. Awesome!
Build a simple radio – Link.