Make an inexpensive desktop scroll wheel
and volume control. By Daniel Walker
The Griffin PowerMate (griffintechnology.com/
products/powermate) is an assignable USB knob
controller that you can set up for many purposes,
such as browsing Google Earth, scrolling web pages,
controlling volume, and so on.
Photography by Ed Troxell
I took a look at some You Tube videos of it in use
and thought it was literally a scroll mouse on its side
with a fancy knob and some software. A few Googles
later, and I found a post on the bit-tech.net forums
about a guy who made his own from a VCR spindle
and an old mouse. I fancied a bit of that, so away
I went, and this is what I came up with.
I call it the PowerFake. It’s made from an old PS/2
mouse, a project box, and an old R/C car wheel.
The basic idea is to liberate the mouse’s scroll
wheel encoder from its circuit board, reconnect it
using wires, and set it up to run off of the knob of
PS/2 or USB mouse with scroll wheel You need
a rotary encoder for the scroll wheel, not an IR
transmitter/detector. A ball mouse is more likely
to use a rotary encoder than an optical one.
R/C car wheel and tire or other circular object you
can use for rotating that fits in your hand easily
Thin metal rod of suitable length to go through your
R/C car wheel, project box side, and the rotary
encoder. It could be a thin nail or a piece from
a large paper clip.
Soldering iron and solder
Solder wick or desoldering pump
Tape or glue to mount the encoder. I used
double-sided foam tape.
Small piece of stripboard, aka perfboard (optional)