1+ 2+ 3 Magnetic Switches from Everyday Things By Cy Tymony
Control many devices from afar with the magnetically sensitive Sneaky Switch.
You will need: Magnet, paper clip, aluminum foil, tape or foam, cardboard, wire, LED or buzzer, 3-volt watch battery
Optional: Ring, battery-operated toy, X- 10 universal interface and appliance module
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.
2. Make a Sneaky 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 the
switch to a 3V watch battery to light an LED,
buzzer, or other low-current devices and toys.
tape (or foam)
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!
Bonus: Detect counterfeit money.
Legitimate currency has iron particles in the ink.
Fold a bill so 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!
Illustrations by Mark Frauenfelder