Remote Volume Knob

Remote Volume Knob
Paulo Rebordao | Make Vol. 16- 2008 | Pdf | 2 pgs | 1 mb

There's nothing like hard work to get your mind
running. Having to get up from the couch to adjust
the volume on my old stereo amp several times
each night got me thinking. I didn't want to buy
a new stereo, so I came up with a plug-in remote
volume controller that you can easily adapt to
anything with a reasonable-sized volume knob.

My circuit uses a Picaxe-08M microcontroller,
which is programmable in BASIC, and a TSOP2238
infrared receiver, which sees signals from any
Sony (or compatible) TV remote. The removable
device hangs off the volume knob, attached with
velcro.

At the top, an R/C servomotor turns the knob
through about 180° of travel, which should be
enough range for most environments. At the
bottom, 3 AA batteries act as a "keel," weighing
that end down so that the knob is forced to turn.
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G-Meter and Altimeter

G-Meter and Altimeter
Double-duty aerospace instrument on a shoestring budget
David Simpson | Make Vol. 16- 2008 | Pdf | 4 pgs | 2 mb

Here's an aerospace instrument you can build for
$5 that will measure the crushing forces that a
model rocket withstands and the rarified strata it
attains. It isn't exactly six-sigma technology in
terms of accuracy, but it's darn fun.

The device, which you install in the rocket's
payload compartment, uses 2 small bands of
heat-shrink tubing that slide over a dowel to record
the maximum G-force and altitude attained. As
the rocket accelerates, the G-force band is pushed
down by washers on a spring, and as the rocket
rises, the altitude band is pushed down the rod by
the expansion of a pressure chamber made from a
pill bottle and a rubber-balloon membrane.
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