28 October 2017
BUILD IT YOURSELF
A stroboscope is a flashing
light with a variable flash rate.
As a calibrated laboratory
instrument, it serves two major
purposes: by optically
"freezing" the motion of a
rotating or reciprocating
machine, it can determine the
operating frequency, and also
allow critical examination of
these machines while in
motion (Figure 1). For us
occasional handymen, they are
useful in examining power
tools like drills, saws, and other
tools in the shop, plus around
the house for fans, kitchen
mixers, blenders, and so forth.
They can even be used to
freeze the motion of a
loudspeaker at a constant tone
to look for causes of distortion.
By Mike Huddleston
Traditional stroboscopes have been expensive nough so that only a few hobbyists or other non-professionals owned them. They used
photoflash tubes that — while truly bright — limited
their flash rate and required high voltage power
supplies. Their heavy power supplies and regular
need for AC power compromised their portability.
With the advent of inexpensive digital control
circuitry and ever-brighter LEDs, some of these
problems have been corrected. It’s now possible to
buy a lab-grade LED stroboscope (at a fraction of
their previous cost) that is portable and even
battery powered. The drawback is that LEDs just
aren’t usually as bright as photoflash tubes.
■ FIGURE 1. The StroboDuino "stopping" a boxer fan with
three color dots applied.