With all the Halloween props on the market, it’s difficult to startle people. I use the word startle because ‘scare’ is now a multi-million dollar Hollywood thing. In this project, you can build a little book
that startles people.
A good Halloween prop needs a “hook” to pull
people in; a visual to keep them interested; then a “shock”
to startle them. This project has all three: a hook (muffled
sound) pulls the victim in; a visual (an eye moving left to
right) keeps things interesting; and then there’s a make-you-jump finale — all in a small 5 by 7 inch book. I have
tested the effectiveness of this little book in my wife’s gift
shop (I didn’t scare any little old ladies — I swear!).
Although I didn’t video any of the reactions, they were
video-quality startles.
What Exactly Does It Do?
It’s a small, odd, old-looking book — with an eye and
eyebrow. It sits quietly on a surface. It then makes a weird
muffled laughing sound. The victim hears the sound and
walks up to investigate. Nothing happens. No, wait! Did
that eye move? They look closer, reaching out to open the
cover of the book — Yikes!
It just jumped at the unsuspecting mark several times,
opening and closing its “mouth.” The book then retreats
to assume its passive-aggressive demeanor — for the next
victim.
All of this is initiated by you. A four-channel remote
secreted in your hand controls all the timing and
functions. Those functions are:
Channel 1. Sound from module
Channel 2. Eye moves
Channel 3. Book hops forward rapidly
Channel 4. Book hops backward rapidly
Let’s Get Started
There is no microprocessor or programming in this
project. The system utilizes a double-sided PCB (printed
circuit board), an L293 quad bridge, two regulator ICs, an
off-the-shelf four-channel transmitter and receiver, two
motors, and a sound module similar to the ones you find
in a greeting card. This project is powered with a standard
nine volt battery, so it is safe for everybody. Most of us
electronics nerds have saved those little sound modules
from greeting cards, but if you don’t have one, you can
just leave it out of the project or head to the dollar store.
The brains are on a double-sided thru-hole PCB.
Figures 1 and 2 are the schematic and board. Keep this
board as small as you can. The inside of this little book is
crowded. Pay attention to the location of each part with
September 2015 23
■ FIGURE 1. Schematic.
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article/september2015_Elwell.
A Printed Circuit Board to go with this article can be
purchased online from the Nuts & Volts Webstore at
www.nutsvolts.com or call our order desk at 800-783-4624.
