SHAKE THE BATTERIES OUT OF
THE PICTURE FOREVER WITH THIS
A TV remote is one of the most commonly
used electronic gadgets. We use it without even thinking about it — that is, until
the batteries quit.
TV remotes use infrared light for communication with the
TV set. Every infrared remote uses AA or AAA batteries to
power an infrared LED, controlled by an electronic circuit that
beams commands according to the buttons that you press.
This electronic circuit is a very low-power device. Nonetheless, every so often the batteries get drained, usually right
when you need them most. And what happens to the used
batteries? Perhaps you send them to your local battery
recycling plant, or maybe they end up in your town’s landfill,
polluting the environment. It would be very nice if we could
use our remote control devices without any batteries at all!
It turns out that it’s easy to bag the batteries, as long as
you’re willing to put in a little manual effort. How about simply
moving your hand back and forth a few times? This motion
represents kinetic energy that can be converted into electrical
energy, sufficient to power any remote control.
Photograph by Sam Murphy
Set up: p. 111
Make it: p. 112
Use it: p. 115
Dhananjay V. Gadre is an assistant professor with the Electronics and Communication Engineering Division, Netaji
Subhas Institute of Technology, New Delhi. Gadre likes to build electronic contraptions for work and for joy. He takes
pride in not being associated with any national or international professional cartel, society, or association.