Site map :

Various stuff
Rotation sensor
Security device
The Robot pages
Lego Ants
Robotarm v1.0
Robotarm v3.0
Tutorial 1
Tutorial 2
Physics of Lego
Measuring strength
Combining motors
Stepper motors
Lego ratchet
Electronic ratchet
1-to-2 multiplexor
2-to-7 multiplexor
RCX Mindstorms
Survey of RCX programming
The famous machines
Turing machine
New Page 1
References and links

Last upgrade to the site:
august 10th, 2002.

There has been 

access to my Lego pages since creation.

This is an unofficial LEGO® web site.
LEGO® is a trademark of the LEGO® Group of companies which does not sponsor, authorize or endorse this site.
You can visit the official LEGO website at:

Copyright 1996, 2000, Denis Cousineau


  1. How to create the necessary pressure in the hoses?

A pump is required. Three alternatives are proposed here:

  1. The small pump

The small pump can only increase the pressure by a very small amount since its inner chamber is so small. However, since it is generally connected to a fast motor (see assembly below), it can produce a reasonable amount of pressure in a small time.

  1. The large pump

The large pump is much more efficient. Its inner chamber is pretty large, so that in a single pump, the pressure can be increase much more. However, it is much more difficult to connect it to a Lego motor because of the presence of a spring. The assembly below shows one way to embed it in a Lego pumping station. I put two shocks to compensate for the spring on the pump. All springs are of equal strengths, but the two shocks are located twice closer to the center of rotation. One new Lego motor is strong enough to active the pump.

  1. A car pump!

This is maybe the most efficient may to have pressure. In fact, it is too much pressure, and the hoses will certainly pop out of there sockets with this characteristic "pop" sound.

If you adopt this last method, you’ll need to regulate the pressure: When a critical pressure is achieved, stop the pump. However, since there is no pressure in the hoses, if the pump is stopped, your pneumatics don’t work anymore. For that reason, you need a pressure tank. See next section to build a pressure tank and a Lego regulator.