by Gerard Fonte
Mr. E. MacHine: The
Enigma Machine — Part 2
Lightning in the Palm of Your Hand — Safely!
Last month, we examined two designs for building
the Enigma Machine. We saw that it is a device that
produces pulses of 1200 volts at a rate of a few
Hertz to a couple of hundred Hertz. Because the high
voltage is completely isolated from the outside, no
significant current flows. Therefore, it’s safe to play with.
This month, we’ll look closely at the vibration effect, as
well as experiment with other properties of high voltage.
The Specifications Table provided is for the
microprocessor (µC) version. There are a few differences
from the 555 timer version. The input voltage for the 555
version must be 12 volts DC with the proper polarity.
Obviously, the physical characteristics will be different if
you used a different case. The output pulse voltage is
different. The µC version outputs a decreasing voltage as
the frequency increases.
The 555 timer version outputs the same voltage at
any frequency. I did this because, at higher frequencies,
the rapid pulses seemed to be on the edge of annoyance
for some people. If you want to maintain high pulse
voltages regardless of frequency setting, change R2 from
1M Ω to 100K Ω. (This is the resistor that connects the
base of the transistor to ground in the µC version.) All of
the experiments described below use this modification.
A substantial amount of research into these effects
has been done. The explanations provided here are based
on that research. However, it is clear that some effects are
subtle and the exact mechanisms are not precisely
known. This means that your own experiments may turn
up something new.
There are a number of factors that can cause variations
in some of the experiments (room humidity seems to be
one of them). The experiments provided are usually
reliable (unless otherwise noted). Be sure to record any
experiments you do to try to determine what these factors
are. It should also be noted that some of these effects are
not well known. In fact, I have not been able to find any
reference to the vibration effect.
Vibration Effect Experiment
Place an empty soda can on the machine and turn it
on to a high rate (see Figure 1). Now, gently brush a dry
finger across the side of the can. (You may need to hold
the can in place with something that’s well insulated —
like a screwdriver handle.) You will feel a vibration at the
frequency setting of the machine, but this only happens
Figure 1. Rubbing the can with a dry finger causes a vibration
at the frequency setting of the machine. You may have to hold
the can steady with an insulator, like a screwdriver handle.
(Don’t touch the can with your hand.) The plate is optional.
Figure 2. The vibration effect can pass right through a person
without any sensation, but the effect is reduced.
NUTS & VOLTS