How to Create a Magnetic Switch Electronics Project

A Sneaky Switch for Everyday Use

By Cy Tymony
Make Magazine: Vol. 7, p. 51

Have you ever dreamed about having the power to turn on and off household appliances and electronics with a wave of the hand? Then this one's for you. Make Magazine brings you the art of making a magnetic activator and a super stealth sneaky switch so you can make the magic happen.

Step 1: Make a Magnetic Activator

You'll want a strong magnet to activate devices from at least an inch away. Tiny rare earth magnets can be found in most micro radio-controlled cars and in the packaging of some hearing aid batteries. Glue a magnet to the face of a ring or a wand or affix it to some object so that when it's near the switch, or moved away, it will cause the desired effect.
Make a Magnetic Activator

Step 2: Make a Magnetic Switch

In this magnetic switch, the paper clip lies across a "spring" of rolled tape, one end hovering just above the aluminum foil and the other end taped down. (A small piece of foam can also be used as the spring.) When a magnet passes over the switch, it tugs the clip to touch the foil, completing the circuit. Connect a switch to a 3V watch battery to light an LED, buzzer or other low-current devices and toys.

Make a Magnetic Switch

Step 3: Connect Switch to a Relay

Your magnetic switch can be attached to a relay to control devices that need higher current. Mount your switch and relay behind the dashboard to secretly activate a cut-off switch, alarm or other car accessories. Or, hook your switch to an X-10 controller and universal interface module to control a variety of appliances. Pretty sneaky!
Connect Switch to a Relay

Step 4: Detect Counterfeit Money

Legitimate currency has iron particles in the ink. Fold a bill so that half of it stands up vertically – If the top edge moves toward your magnet, it's the real deal. If not, phone the Secret Service!
Detect Counterfeit Money

If you have an electronics story or project you'd like to share, please email [email protected]