• 2 empty toilet-paper rolls
• 2 rubber bands
• wax paper
• heavy thread
• an old wax candle
• 2 toothpicks
Stretch a piece of wax paper over one end of each toilet-paper roll. Hold it tightly in place with a rubber band.
Rub some thread with an old wax candle so that it is covered with wax.
Poke a hole in the middle of the wax paper on one of the rolls. Push one end of the thread through the hole. Tie a toothpick to it. The toothpick will keep it from pulling out of the hole. See Picture. Attach the other end of the thread to the other roll in the same way.
Pull the thread tight and your intercom is ready to use. You speak into one end, and somebody else listens at the other end. When he speaks, you listen. It works well when the thread is stretched out straight and is not touching anything.
Stretch the thread from one room to another.