Your EMF Explorer Badge is built and powered on - now what? Here's a field guide to the signals hiding in your everyday surroundings.
Hold your badge close to these everyday devices and listen through your headphones.
Detect the low-frequency hum given off by chargers, adapters, and power bricks.
Hear how a switch connects the power circuits running through the walls around you.
Pick up the internal operational emissions of laptops, desktops, and displays.
Dimmer switches and motor speed controllers produce distinctive variable-frequency noise.
Listen for the power circuit emissions of phones and communication equipment.
Detect emissions from the transformer and magnetron - from a safe distance, of course.
Hear the internal electronics at work - notice how the sound changes between connecting and transmitting.
Pick up IR emitters and other emissions when a remote is in use.
Scooters, parking meters, vending machines, "open" signs - explore everything you can find.
New to listening for EMF? Try these starter challenges on your own or with a group:
Turn on a pair of Bluetooth headphones near your badge. Listen for the moment they connect to a phone - does the sound change?
Hold your badge near a laptop touchpad. Tap and drag your finger across it - what does touch sound like?
If you have access to a dimmer switch, slowly turn it up and down while listening. Notice how the pitch shifts.
Take your badge outside. Parking meters, "open" signs, scooters, and streetlights all have stories to tell.
Watch this Veritasium video on how electronic signals create a magnetic field around wires to move electrons.
Read NASA's guide to the electromagnetic spectrum for the bigger picture.
Explore a broad range of frequencies with the University of Twente's WebSDR tunable receiver.
Explore the KiCad design files on the EMF Explorer Badge GitHub repository - or read about it in Make: Volume 90.
Grab the kit and start exploring the signals hiding in your world.
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