====== Pneumatic Cylinder With One Switch ======

**Keywords:** Lego, Pneumatic, Sequencing, Circuit, Cylinder
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==== Motivation and Audience ====
The goal of this tutorial is to teach students how to build a basic pneumatic switch. Pneumatic sequencing is built around using pistons to move switches and direct air flow. Using this simple switch, students will be able to change the direction of one current using one pneumatic cylinder.
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==== Parts List ====
^ Part Description                       ^ Part #    ^ Qty|
| Technic Axle Pin                       | 3749      | 6|
| Technic Pin With Friction              | 4459      | 6|
| Technic Cross Block 1 x 2 (axle/pin)   | 6536      | 1|
| Technic Brick 1 x 14 with holes        | 32018     | 2|
| Technic Beam 3 x 3 x 0.5               | 32056     | 4|
| Technic Axle 2 Notched                 | 32062     | 1|
| Technic Pin Long                       | 32556     | 1|
| Technic Pneumatic Valve with Pegholes  | 47223b    | 1|
| Technic Pneumatic Cylinder             | 47224c01  | 1|
| Technic Axle Joiner Inline Smooth      | 59443     | 1|
| Pneumatic Hose - Various Length        | 5102      | 1|

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==== Construction ====
**Step 1:**\\
Using four of the pins with friction, attach the two 1x14 bricks to each other. Attach the axle pins and the remaining two pins with friction to the outsides of the brick in the holes depicted.\\
{{:screen_shot_2016-02-23_at_8.34.19_pm.png?nolink&200|}}
{{:screen_shot_2016-02-23_at_8.34.28_pm.png?nolink&200|}}

**Step 2:**\\
Attach two of the 3x3x0.5 beams to one side of the bricks and use and axle pin to attach a pneumatic cylinder with the ports facing away from the bricks. Mirror the beam and axle pin structure on the opposite side as shown for stability.\\
{{:screen_shot_2016-02-23_at_8.45.37_pm.png?nolink&200|}}
{{:screen_shot_2016-02-23_at_8.45.43_pm.png?nolink&200|}}

**Step 3:**\\
Connect a pneumatic valve to the remaining pins with friction. With the valve switched to the left side, attach an axle joiner, a notched axle 2, and a 1x2 cross block to extend the lever to the heigh of the cylinder.\\
{{:screen_shot_2016-02-24_at_11.54.22_pm.png?nolink&200|}}

**Step 4:**\\
Using a long pin, connect the cross block to the pneumatic cylinder so that the switch may be controlled with the expansion and contraction of the cylinder.\\
{{:screen_shot_2016-02-24_at_11.54.35_pm.png?nolink&200|}}
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==== Final Words ====
These pneumatic switches are analogous to electronic switches. Air would be flowing from some source into the center port of the switch. Using some source of air to control the motions of the piston, students can manipulate the switch to direct the flow of air from the center port to either the left or right ports which is essential to building complex pneumatic systems.