Grown men scream in fear when the Pumpkin Popper attacks!

For 2001, David cooked up a simplified version of this scare. It's almost as scary as the original, and much easier to build.

• Description
• Complications
• Initial Photos
• More Photos
• Result

• Related Pages

The clever part of this gizmo is the way that the design works around the height of the pneumatic cylinder.

• It's a fact of life that a normal pneumatic cylinder will less than double when activated. If the cylinder is 2' long at rest, when activated it will be a tad less than 4' long. [There are exceptions, multistage cylinders that telescope like radio antennas. We can't afford those.]
• It works the other way, too. If you want something to jump up 2', you start with a 2' cylinder that extends to a total of 4'.
• We wanted to use a long cylinder to get the popup to jump far out of the can, hence the use of the bicycle pump which is much longer than a screen door closer. But where do you put the extra 2' length of the cylinder before it is activated?
• We put it inside the body of the pumpkin.

The pumpkin on the left has the piston mounted to the bottom. The pumpkin can be no larger than half the height of the trashcan because of the height of the pneumatic cylinder.

The pumpkin on the right puts the pneumatic cylinder insode the pumpkin, This lets us use a larger pumpkin.

For a popup, we used a hollow plastic pumpkin almost as tall as the trash can is. It has a hole in the bottom. The pneumatic cylinder extends up through the hole in the pumpkin and into the body. The cylinder's piston is attached to the inside top of the pumpkin. The lid of the trash can is attached to the top of the pumpkin and the top of the piston.

When the cylinder is activated, the piston extends, lifting pumpkin into view, and pushing the lid up like a hat on top of the pumpkin.

The pumpkin also uses an amplified scream box and a strobe, so when it triggers, you get a strobe light on the pumpkin and a startling sound.

Initial Photos

We started with a hollow store-bought pumpkin about two feet tall.

The pumpkin has a light inside, provided by a C7 lamp in a simple pinch-light fixture. Remove it and use for some other project.

The pumpkin shell was made in two pieces. The bottom is a plastic disk glued into place. Pry it out, to leave a nice hollow shell.

Just a simple galvanized trash can.

Here's the pumpkin shell just sitting in the bottom of the trash can.

As purchased from the store, the handle for the trash can is merely crimped on the lid. To the left of center is a pop-rivet that helped hold things together during construction. To right of center is the threaded end of the bicycle tire pump, with a nut on the end.

More Photos

This jumble consists of most of the support equipment for the popup.

You can see: Haunt Air Manager (HAM), trigger relay, scream box, X-10 module.

Not shown: amplified speakers, strobe.

In normal operation, all of this stuff is crammed into the bottom of the can.

This small hole in the bottom of the can is where the working bits inside the can communicate with the outside world.

When ready for use, only two things come out: an air hose to run the pneumatic cylinder, and a 110 VAC cord for power and control.

All of the support equipment is inside the bottom of the can.

This is a unique view, looking up from the inside of the trash can, along the pneumatic piston, to the top of pumpkin. The arrow shapes in the upper left are the eye openings molded into the pumpkin.

This interior view of the pumpkin shows another detail: a small incandescent lamp inside the pumpkin.

The reflector is made from a tin can.

Looking down into the can, we don't see much ... because the support equipment hasn't been stuffed in yet.

The base of the bicycle pump is securely fastened down to a piece of wood, which is itself screwed down to the bottom of the can.

David wanted the pumpkin to pop up in darkness. Only when the pumpkin was fully deployed would the action start: light inside the pumpkin, strobe light shining up on the pumpkin, and canned scream.

The thing to right of center is a microswitch, with the actuator poking down into the top of the bicycle pump top. When the pump piston is fully extended, it actuates the microswitch, powering up the strobe light, incandescent light, and triggering the canned scream.

Result

This picture of the pumpkin in operation was taken with a flash, so illumination details are lost.

You can see the light coming from inside.

This photo was taken by the pumpkin's "natural" illumination.

Note the nice image of the mouth cast on the ground in front of the trash can.

• compressed air introduction
• Turn the pressure on and off with solenoid valves.
• Turn pressure into motion with pneumatic cylinders.
• compressors

Other projects that go into the pumpkin popup:

• our air control assembly: HAM
• improvised a pneumatic cylinder from a bicycle pump
• remote control with X-10
• trigger relay
• scream box

Pneumatic props:

• popup skeleton
• giant spider
• pumpkin popup [this page]

Thank you for visiting. Your comments are welcome.
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