The world is full of invisible signals. This badge lets you hear them. Hidden electromagnetic frequencies are all around us, and so much can be discovered through listening to these waves. The way that Bluetooth hardware sounds when it’s operating. How cell phones sound when they are transmitting data. What a laptop touchpad sounds like when it detects touch. The electronics world is invisibly emitting sounds around us all the time that we are mostly unaware of. The beautifully detailed art on the completed PCB glows with the onboard LED, making it a great wearable badge even when you're not actively scanning No previous electronics experience is required to appreciate and use this badge, and it’s a great way to learn more about your world by exploring the different properties of our surroundings. Please note: Requires the use of a soldering iron and runs on two AAA batteries (not included). Suitable for ages 14 and up. Adult supervision recommended for younger builders. Kit includes EMF Explorer PCB Board x1 100pF Capacitor (Tan) x2 10uF Capacitor (Blue) x2 4.7uF Capacitor (Sm. Black) x2 100mH Inductors (Lg. Black) x2 LED x1 IC Chip 2115D x1 100k Resistors (Tan) x2 100ohm Resistors (Blue) x3 DPDT Slide Switch x1 1/8" Stereo Jack x1 AAA Battery Holders x2 (batteries are not included) Printed assembly guide with component placement diagram and QR code linking to additional assembly resources ... and a shiny sticker! To build the kit you will need a soldering iron, solder, and clippers. You'll also need 2 x AAA batteries and headphones (or something else with a 1/8" / 3.5mm audio plug) to listen to the sounds. Resources Assembly guide (and more details about how the board works) Interactive frequency monitor EMF Explorer Zine Explore the Kicad files at the EMF Explorer Badge Github Repository. Read about the EMF Explorer badge in Make: Volume 90! Instructions Page What is EMF? Every conductive material can act as an antenna, receiving small currents from electromagnetic waves, which can be amplified and heard. Conversely, anything that sends out various electronic signals will transmit those signals into the space-time continuum, which can be picked up by a coil of wire, like the inductors on the EMF circuit board. Electromagnetic disturbances from everyday household electronics tend to fall between 20 Hz and 20 KHz, within the range of human hearing. The EMF explorer circuit amplifies those signals up to the human hearing range (by a factor of 1000x). How Does It Work? Inductors on the board detect EMF signals. When a changing magnetic field is present near the inductor, it induces a voltage, which can be used to detect the magnetic field. What Can You Detect? AC Power Supplies: Detect low-frequency hums. Switched-Mode Power Supplies: Detect high-pitched whines or buzzing. Computers and Monitors: Detect internal operational emissions. Dimmer Switches and Motor Speed Controllers: Detect variable-frequency EMF noises. Telecommunication Devices: Detect power circuit emissions. Inductive Loads: Detect humming from transformers and inductors. Microwave Ovens: Detect emissions from transformers and magnetrons. Bluetooth Headphones: Detect internal electronics emissions. Remote Controls: Detect power management and signal modulation emissions. Explore other devices to see what else you can detect!
