Animating a prop with an air cylinder (pneumatic cylinder) requires several pieces to make it happen. First of all you need a pneumatic cylinder to cause the actual movement, a valve to stop and start the flow of air, tubing to connect all the pieces together, fittings to join the tubing to the components, an air supply and finally a trigger to control the device. An auxiliary air storage tank is optional.
Before positioning your equipment in place or connecting the cylinder to a prop, connect together the pieces of your system to test for proper function.
Caution: Once connected to pressurized air, the cylinder rod may actuate very rapidly and unexpectedly. Always place the cylinder so that the rod is directed away from people. The rod should be pointed into open air so that it cannot harm anyone or push against an object forcing the cylinder backward toward you. Always start testing with minimal air pressure. Always operate a prop with the minimum pressure needed to get the job done and no more.
Typically the air supply does not need to be near the prop. If you are using a compressor, the noise may detract from the operation of your prop and it is desirable to separate the two. The compressor can be connected to control valve, a splitter or an auxiliary storage tank with standard air hose and quick connect fittings. This is preferable to use of the tubing we'll use later because these hoses are more durable than the tubing and can withstand more punishment. If you will be driving multiple props from one compressor, it is a good idea to add in auxiliary storage tanks to ensure adequate air supply during peak demand.
A small compressor should be able to provide more than enough air supply for one or two cylinders. However, if you are driving those cylinders continuously or you have more cylinders, your compressor may be taxed to keep up with demand. It is always a good idea to double check all your fittings from end to end to make sure you don't have any air leaks. Even small leaks can add up. All hoses and quick connect connectors should be be tightly connected together and gas rated teflon tape should applied to all male fittings to get air tight seals.
With your air supply hose connected to your compressor (but with no pressure) you can connect the air supply to the valve and the tubing between the valve and the cylinder. Use of push connector fittings are a vast improvement over the old barb fittings. Each push connector fitting should have gas rated teflon tape wrapped onto the male threads before the fitting is screwed into the valve and cylinders. Tighten the fittings by hand and then give them a quarter to full turn with a wrench to seal them tightly.
Depending upon the valve and cylinder you use, the number of connections will vary. If you are using the most versatile, 5-port, 4-way valve, you will start by connecting the air supply to the "In" port. One of the ports will be "Normally Open" or "NO" and one will be "Normally Closed" or "NC". If you have a double-acting cylinder, then you will use both of these ports. The "NC" port is the port that opens when you electrically trigger the solenoid valve. When the valve opens, your prop will be actuated. Connect this port to the side of your cylinder that should receive pressure to actuate the prop. Connect the other port to the side of cylinder that should return the prop to the "resting" position.
If you are using the push-to-connect fittings, then making the connections is very simple. Cut your tubing with a razor knife to length, plus a little slack to prevent pinching. Insert the tubing to the push fitting on the cylinder and to the valve.
The valve has two exhaust ports. You don't need to do anything with these ports, however, you can add a flow control or a muffler. The muffler is used to reduce the noise from venting air. The flow control allows you to adjust the rate of exhaust and thus slow the movement of the prop.
If you do not use one of the output ports, it will need to be capped, otherwise air will blast out while the valve is directing the flow path through that port.
Finally, the solenoid valve needs a trigger. Valves are available for different voltage sources, be sure to connect it to the proper power source for the solenoid. You can connect the valve to a manual switch, such as a simple on-off light switch, a momentary switch such as a push button or it can be triggered with various sensors. A pressure mat makes an electrical connection when someone steps on the mat. When someone steps near the prop and stands on the pressure mat, the circuit is made, the valve is energized and the prop is actuated. Similar sensors include motion sensors, infra-red sensors and light-beam sensors. For automated props, you can connect the valve to a variety of "key banger" controllers that will record and play back a sequence of on-off signals to actuate the prop in a preset way on demand.