■ FIGURE 15 A and B. Prop Dropper servos and Prop-1 board
mounted in plastic bucket.
■ FIGURE 16 A and B. Prop Dropper bucket with
power lead and suspension wire.
it detects motion (I've even managed to startle myself!), I
wanted to experiment with other methods of triggering. If
you're wanting to have pin-point control of when things
drop, you can use this simple pill bottle button trigger
(Figure 17). I found that palm-sized prescription drug bottles with child proof caps make for very good enclosures
for a home-brew handheld trigger. The device is created
by drilling a hole in the bottom of the pill bottle (Figure
18) and mounting a small pushbutton switch. Though pretty much any pushbutton momentary switch will do, I used
a RadioShack CAT #275-1571 model switch (Figure 19).
Next, drill a hole in the cap and mount a female RCA jack
(Figure 20). By using a female RCA jack on the button
and also on the Prop Dropper itself, it's easy to get the
right length of cable by simply using any male to male
RCA cable you happen to have lying around (Figure 21).
(that should get you thinking!), Easter eggs, or even a
Birthday card. You don't have to limit the Prop Dropper to
the Halloween decorations bin as you can surprise your
guests or family with any seasonal or occasional item that
the servo motor can hoist. In fact, you could reduce the
design to a single servo that held a small paper cup. Fill
the cup with confetti and you could have a synchronized
confetti drop for a party!
Smaller or Stronger — The first Prop Dropper I
constructed used standard servos only because they
were what I had handy. It is quite possible to build a
much smaller or even much larger Prop Dropper using
some of the more powerful or more compact servo
motors available on the market.
VARIATIONS ON A THEME
At this point, you should have a fully operational Prop
Dropper to use for Halloween. However, I want to point
out that this little design has quite a bit of hack potential.
In the course of developing this device, I came up with
a bunch of improvements and modifications, some of
which I've already built and tested. As a way to excite your
imagination, I've compiled a list of the various ideas I had
on how you can alter, update, and re-use the Prop
More Droppers = More Fun! — The EFX-TEK Prop-1 can
accommodate up to six servo motors along with a motion
sensor and still have one I/O pin left over! It is possible to
connect six servos and have the software trigger a
sequence of drops down a hallway.
Sound Effects — Since the Prop-1 board uses a Parallax
BASIC Stamp 1 chip, it is capable of using the SOUND
command to create noise. It's possible to add some lines
of code to create a siren-like sound or a loud chirp to help
draw attention to the prop when it drops.
Use a Different Prop — Though all my examples above
show the Prop Dropper being used to drop a Halloween
scare, the Prop Dropper could just as easily be used to
drop snowflakes, Christmas ornaments, a sprig of mistletoe
■ FIGURE 17. Pill bottle pushbutton
Pull Up or Sideways! — Using some pulley, or even a
couple of cup-hooks, you can place the Prop Dropper on
the floor and have it drop "up." This may allow you to
drop something from a space that normally wouldn't
accommodate the entire mechanism overhead, or allow
you to place a scare without the bulk
of the Prop Dropper overhead to
give it away. Also, consider that if
you need the deployment to be
soundless, you could move the Prop
Dropper to another location and just
■ FIGURE 19. RadioShack CAT
#275-1571 pushbutton switches.
■ FIGURE 18. The push button switch
mounted in the bottom of the pill bottle.