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156 Masterpiece 4 • PneumADDic II

Figure 1.3 Pneumatic Switch Positions

Inlet/Outlet Outlet/Inlet
Inlet

Release Pressure Off Off Pressure Release

Figure 1.4 shows a complete pneumatic circuit starting with a pump that pressurizes
the pressure tank.The pressure from the tank is fed to the pressure inlet on a switch.The
inlet/outlet ports on the switch attach to a piston. LEGO makes three colors of pneu-
matic tubes:

■ Blue
■ Light gray
■ Dark gray

Figure 1.4 A Pneumatic Circuit with an Expanded Piston

The most common method of attaching hoses is to use blue pneumatic tubes from
the pumps to the tank(s), and from the tanks to the inlets on the switches. In Figure 1.4 I
used light gray tubing to connect the left port of a switch to the base of the piston, and
dark gray tubing to connect the right port of the switch to the top inlet of the piston.

NOTE
When building PneumADDic II, use the hookup conventions described previously.
The only exceptions are for special cases that are described in their corre-
sponding steps.