====== Motorized Lego Air Compressor ======

**Keywords:** Lego, Pneumatic, Sequencing, Circuit, Cylinder, air compressor
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==== Motivation and Audience ====
This tutorial is to create a source for air flow for pneumatic circuits. Using the battery box and the power functions M Motor, electric current is turned into rotational force which translates into reciprocating force to power the pump. This pump compresses the air so that when the switch is facing the left side, the will be a constant air flow into the tank and when the switch is flipped, the pressure from the pump is relived into the atmosphere.
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==== Parts List and Sources ====
^ Part Description                       ^ Part #    ^ Qty|
| Technic Axle 3                           | 4519      | 1 |
| Technic Pin With Friction                | 4459      | 17|
| Technic Pin Long with Friction           | 6558      | 1 |
| Technic Pin Long                         | 32556     | 2 |
| Technic Bush with Two Flanges            | 3713      | 1 |
| Technic Beam 3                           | 32523     | 1 |
| Technic Beam 5                           | 32316     | 4 |
| Technic Beam 7                           | 32524     | 5 |
| Technic Beam 7 x 5 with Open Center 5 x 3| 64179     | 1 |
| Technic Brick 1 x 14 with Holes          | 32018     | 1 |
| Technic Brick 1 x 4 With Holes           | 3701      | 2 |
| Technic Brick 1 x 6 with Holes           | 3894      | 2 |
| Technic Plate 2 x 4 with Holes           | 3709b     | 1 |
| Technic Plate 2 x 6 with Holes           | 32001     | 1 |
| Technic Pulley Wheel 5D                  | 3736      | 1 |
| Technic Pneumatic Valve with Pegholes    | 47223b    | 1 |
| Technic Pneumatic Pump 2 x 2 x 5         | 2797c02   | 1 |
| Technic Pneumatic Air Tank               | 58120     | 1 |
| Pneumatic Hose - Various Length          | 5102      | 1 |
| Electric Power Functions M Motor         | 8883      | 1 |
| Electric Power Functions Battery Box     | 88000     | 1 |

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==== Construction ====
**Step 1:**\\
Attach the two 7x5 open centered beams together using pins with friction. Attach more pins with friction on the outside in the pattern shown. These pins will be used to help mount the motor and pneumatic components. Add long pins with friction on the bottom to provide supports for a stand. In this design, the pump hangs off the side below the level of the 7x5 beam, and thus a stand is necessary to raise it up.\\
{{:screen_shot_2016-02-24_at_11.38.40_pm.png?nolink&500|}}
{{:screen_shot_2016-02-24_at_11.38.52_pm.png?nolink&200|}}

**Step 2:**\\
Connect the two 1x4 bricks and the 1x14 brick to the beams as shown. The motor and air tank have stud slots on the bottom so these will be used to make a base for those. Add two small beams to the front of the frame so that we can mount the pump and then attach more beams to the long pins on the bottom to build a stand for the compressor.\\
{{:screen_shot_2016-02-24_at_11.41.41_pm.png?nolink&400|}}
{{:screen_shot_2016-02-29_at_12.45.51_am.png?nolink&440|}}

**Step 3:**\\
Attach a 2x6 plate to two more 1x4 bricks on top of the frame with the air tank on top. On the other end of the frame, attach two 1x6 bricks with the M Motor on top. Attach the pump to the front of the frame with the pressure port facing upwards.
{{:screen_shot_2016-02-29_at_12.47.29_am.png?nolink&400|}}
{{:screen_shot_2016-02-29_at_12.47.50_am.png?nolink&400|}}

**Step 4:**\\
Connect the motor to the pumps knob using an axle 3, a bush with two flanges, a pulley wheel 5D, and a long pin without friction. This connection will turn the rotation motion of the motor into reciprocating motion on the pump. Also attach a pneumatic valve to the side of the frame. This valve will be used to turn compression on and off.\\
{{:screen_shot_2016-02-29_at_12.48.44_am.png?nolink&400|}}
{{:screen_shot_2016-02-29_at_12.48.52_am.png?nolink&400|}}

**Step 5:**\\
Finally attach the pressure port from the pump to the center port of the valve. Connect the right port of the valve to one of the input ports on the air tank. The other port on the air tank will be used to direct air flow into your circuit.\\
{{:screen_shot_2016-02-29_at_12.50.28_am.png?nolink&400|}}
{{:screen_shot_2016-02-29_at_12.49.52_am.png?nolink&400|}}
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==== Final Words ====
For small circuit with few pistons, manually pumping the pneumatic pump provides adequate pressure, but it is not automatic. This motorized compressor provides adequate air flow for medium sized pneumatic circuits. In future designs, if you find this compressor is not meeting the circuits needs, more components can be added such as a more powerful or second motor, a second air tank, or more pumps.