Make a microphone out of a matchbox and pencil leads. Listen to sounds and music from the other side of the house using this DIY microphone. Simple audio electronics project. You will also need a battery, some wires and clips, and a pair of headphones or a speaker.
This is an example of a “variable resistance” microphone which was commonly used in early telephones (such as the Carbon Microphone). The piece of pencil lead sitting on top of the two supporting leads vibrates with the matchbox which acts as the variable resistor. Modern production microphones do not use this technique for capturing sound, instead relying on magnets or charged electrical plates (Learn more about microphones on our Lesson – The Science and Engineering of Sound)