There are plenty of ways to get motion into your haunt. Most of them involve electricity. But every technology has strong and weak points. Electricity - at least the kind that is easily available in the home - isn't terribly good at sudden forceful linear motion. And that's just what compressed air is good for.
![[photo]](pnuint_BlockDiagram.bmp)
We have a page on compressors and other air sources.
The air from a compressor might need conditioning for several reasons:
At Wolfstone, each prop has its own Haunt Air Manager (HAM) that provides local pressure regulation. Most compressors come with an output pressure regulator. I'm not aversed to using regulators in both places: 125 PSI in the compressor tank, 75 in the hoses, and 30 in the prop.
![[photo]](pnuint_FRL.jpg)
This unit from Harbor Freight Tools
performs filtration, regulation, and lubrication.
You use lots of hose and a distribution manifold to send the air to more than one place.
![[photo]](pnuint_manifolds.jpg)
Both of the units shown here work the same way: they accept air through a male quick-connect; they dispense air through three female quick-connects. Note that the female quick connectors contain built-in valves so that air is not released through unused connectors.
You can get manifolds like these already assembled.
We put these together ourselves from threaded manifolds and quick connectors from Harbor Freight Tools.
You can save money on hose if the distribution manifold is located close to the props.
This way, instead of three long hoses to the props, you can have one long hose from the back yard to the front,
and three short hoses distributing the air to the props in the front yard.
In 2000, we had only two pneumatic props. We put a manifold on the roof, using it as a 2-way splitter, near the giant animated spider. If we end up using the spider again in 2001, we will have one manifold on the roof, and one on the front yard.
You can buy short 10-foot hoses, but they are relatively expensive. We prefer to start with a good grade of 50-foot hose; cut it into smaller sections, and add the appropriate connectors to them.
![[photo]](pnuint_conversion.jpg)
The hose-end farthest to the left was purchased with a nice 1/4-inch NPT connector. All we needed to do was thread on a quick connector.
The connection in the middle was added to the cut end of a hose.
First, a barbed connector was shoved into the end.
Then a hose-clamp added to secure the barbed connector.
Finally, the quick connect was threaded on the exposed end of the barbed connector.
We build our solenoid valves into a standard assembly that we call the Haunt Air Manager (HAM).
NOTE - The solenoid valve should be as close as possible to the prop, in order to get a fast, crisp animation. If the valve is far away, turning it on must first pressurize many feet of air hose, before the pressure can do useful work in the piston that drives the prop. The result is a time lag, and sluggish deployment.
In order to meet the minimum requirements, you have to have a compressor with a suitable rating. In order to keep from exceeding the maximums, you need a regulator.
It is theoretically possible to use a single regulator at the compressor and run everything off
of that.
But this only works if all of your air-driven equipment wants the same pressure.
I prefer to distribute compressed air straight out of the compressure,
and then put a local regulator where the air will be used.
This insures that everything can get exactly the pressure or flow it needs.
The most common way of doing this is the "diaphragm" regulator.
The diaphragm is a valve that balances air pressure against pressure from a spring.
When the output pressure is too low, the diaphragm is pushed open by the incoming air pressure
and air goes through.
When the output pressure reaches the desired level, the diaphragm is pushed closed and air stops flowing.
Diaphragm regulators tend to have boxy rectangular bodies with large control knobs on the top.
The control knob usually has a locking mechanism so that, once set, the pressure stays set.
It is common to see regulators with a pressure gauge on them, but this doesn't always happen.
Before using any pressure regulator, study it carefully.
Make sure that you know:
In general, start out with the pressure on zero.
Then slowly crank it up until you get the desired effect.
One quick way to judge the quality of a diaphragm regulator is to determine the
material used in construction of the body.
In general, the materials range from:
Some commonly available diaphragm regulators:
We have used a lot of these in the past, but they seem to be discontinued in favor of #90590.
NOTES:
When the air is going into something that keeps using a lot of air (like a spray gun),
restricting the air flow path can affect the pressure.
Because of this, flow regulators are sometimes labeled and sold as pressure regulators.
This is a dangerous misnomer!
If a flow regulator is used to regulate pressure, and the device stops using air,
a dangerous situation can develop.
Even on the lowers setting, with the smallest possible aperture,
air will continue to leak through the regulator.
(Think of it this way: a slow, but steadily dripping faucet can fill a bucket.)
The slow but steady flow will continue until the pressure is the same on both sides.
If you are starting with a compressor that puts out 120 PSI,
and use a flow regulator to throttle it back to a "safe" 40 PSI,
as soon as you turn off the thing, pressure will gradually build up to that 120 PSI - not so safe.
Some commonly available flow regulators:
Pneumatic cylinders can be purchased new, found used, and improvised from a variety of materials.
There is occasional debate on the safest, best, and cheapest form of pneumatic cylinder.
We doubt that there is any one true "best".
The best piston for your application depends on your applicatin and all of its requirements.
In some of our projects, we have used a improvised pneumatic cylinders
made from screen door closers and
bicycle pumps.
The standards apply to assemblies that we think likely to be swapped, which includes:
For more information, please see
our preferred standards.
Regulator Basics
There are two kinds of regulators: pressure and flow.
Never confuse a pressure regulator for a flow regulator!
If you put a flow regulator where you need a pressure regulator, you could blow up something.
Pressure Regulators
A pressure regulator does exactly that.
It insures that the output pressure stays at or below a preset level.
Some subscribers to Halloween e-mail lists have reported problems with regulators
made with plastic or pot metal bodies.
Other people have excellent results.
![[photo]](pnuint_HF_44938.gif)
![[photo]](pnuint_HF_90590.gif)
I bought four harbor freight regulators last time they went on sale. I hooked them up today to a manifold I made out of black pipe. 2 failed and started leaking bad at 30 psi, the other two failed around 80 psi.
You might want to go with a well-known brand.
Flow Regulators
A flow regulator directs the air through an opening that can be made larger or smaller.
When you tighten down the opening, less air flows through.
When you release the opening, more air flows through.
![[photo]](pnuint_HF_36797.gif)
![[photo]](pnuint_HF_32905.png)
Pistons
Compressed air can provide your animated
Halloween gear with forceful, rapid linear action by activating a pneumatic cylinder (piston).
Standards
Whenever possible, we like to build our haunt equipment to clear standards that affords us mass-production
and interchangability of components.
In the pneumatic area, this means:
Sticking to these few, simple standards helps us deal with unexpected problems.
The hose is too short? Add another 10-foot section with a snap.
Solenoid acting funny? Unsnap the HAM assembly and snap in another.
Individual props are only standardized in that they take their air through snap-on quick connectors.
Internally, they may or may not use standard components like air cylinders.
Connectors
There are many different ways to make a connection between pneumatic components.
Here are some common ways:
Fittings and parts
We get a lot of our pneumatic fittings and parts from
Harbor Freight Tools.
Here are some interesting parts that they carry (prices as of January 2002):
| model | price | description | notes |
| 32905 | $2.99 | brass flow regulator | |
| 36797 | $5.99 | air pressure regulator | BEWARE - actually a flow regulator |
| 32872 | $9.99 | 1/4" air diaphragm regulator | a true pressure regulator |
| 42444 | $2.99 | 5pc brass quick-connector kit | assortment; often on sale for $1.97 |
| 4873 | $3.69 | 5pc steel quick-connector kit | assortment; often on sale |
| 34700 | $6.99 | 5-pack of F quick-connectors with M thread | |
| 34701 | $7.99 | 5-pack of F quick-connectors with F thread | |
| 34704 | $2.99 | 5-pack of M quick-connectors with M thread | |
| 34705 | $2.99 | 5-pack of M quick-connectors with F thread |
Note:
Thank you for visiting. Your comments are welcome.
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