DIY microphone

You’ve never plugged a cup into your phone? What are you waiting for?

10 minutes


  • Carefully review the general safety advice on the back of the box cover before starting the experiment.
  • Do not let children under 8 years old handle small magnets.
  • Disassemble the setup after the experiment.

Step-by-step instructions

Phones without a headphone jack will require an additional adapter (not included in the set).

This time, you will speak, and the phone will record your voice. Disconnect and reconnect the coil wires—this will help your phone to “accept” the coil with the amplifier as a microphone.


Use the recorder from the app and listen to how it turns out!



  • Dispose of solid waste together with household garbage.

Scientific description

In this experiment, the simple microphone setup includes the coil , the magnet , and the cup , which work together to detect sound . Although sources of sound are all around us, it’s easiest to simply use your voice for this experiment.

When speaking, you create sound waves  by making the air vibrate with your vocal cords. These oscillatory vibrations promptly propagate through the air and reach the bottom of the cup , pushing it, and it starts to vibrate, too, along with the attached magnet . Next, these oscillations of the magnet , set adjacent to the coil , create in the latter electric current, which periodically changes directions following the movement of the magnet . Сhanges in the direction of the current are recorded in the form of an electrical diagram  in your phone.

The louder you speak into the cup , the harder the air vibrations push the bottom of the cup . The more dramatically it arches, the stronger the electric current in the coil . Finally, your phone records the value of the electric signal from the coil . This is how your phone registers the sound and its volume.