Measurement

Site map :

Various stuff
Adder
Rotation sensor
Towers
Security device
The Robot pages
Lego Ants
Robotarm v1.0
Robotarm v3.0
Computer-robot
Circuitry
Program
Tutorial 1
Tutorial 2
Physics of Lego
Measurement
Motors
Measuring strength
Combining motors
Stepper motors
Ratchets
Lego ratchet
Electronic ratchet
Multiplexors
1-to-2 multiplexor
2-to-7 multiplexor
Pneumatics
Pressure
Regulator
Measure
Control
RCX Mindstorms
Survey of RCX programming
PRO-BOT
History
Examples
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 LEGOŽ web site.
LEGOŽ is a trademark of the LEGOŽ Group of companies which does not sponsor, authorize or endorse this site.
You can visit the official LEGO website at: http://www.lego.com

Copyright 1996, 2000, Denis Cousineau

 

Lego Brick measurements.

Height, width, and weight

In the following sections, torque of a Lego motor and strength of pneumatics are all measured using Lego bricks as weight. It is therefore necessary to know their dimension and their weight.

The standard 4 ´ 8Lego brick is constructed as follow:

4 X 8 brick with measurements

A 1 ´ 1 Lego bricks can also be measured in terms of bump:

Width   1 bump 0.80 cm
Height   1.2 bump 0.96 cm
Height of a plate   0.4 bump 0.32 cm

As seen, one brick and two plates on top of each other equal 1.2 + 2 ´ 0.4, or 2 bumps (or equivalently in cm: 0.96 + 2 ´ 0.32, or 1.60 cm). This represents exactly 2 bumps high, so that a beam on the side can connect nicely with horizontal beams separated by two plates.

Its weight is 2.5 grams each standard Lego brick. With 400 of them, you have exactly a kilogram (that is, approximately 2.2 lb).

Angles

The new beams are very convenient, but also composed of a weird angle. If you place them on a wall, as shown below, we see that the 1-angle beam is adjusting perfectly over holes located at 3 bumps on the horizontal and 4 bumps on the vertical. This is a triangle with sides 3-4-5, as you certainly remember from your trigonometry courses. What is less known is that this triangle forms an angle of 36.87° (you can check this by noting that cosine of 36.87 is 0.8, or 4 bumps for a radius of 5 bumps; similarly, sine of 36.87 is 3/5, or 0.6). The two-angle beams are simply composed of 45° angles, easier to manage...

angles.gif (57768 bytes)

Method of measurement.

Of course, it is merely impossible to take one brick, and arrive to the above precision. The most accurate technique to measure small things is to measure a lot of them, and then divide by the number of measured objects. To measure the length of a brick, I noted that in 1 meter (100 cm), exactly 125 bumps could be assembled side to side. This lead to the simple calculation that 1 bump is 4 fifth of a cm, or 0.8 cm. Similarly, in a meter, I can put 104 bricks on top of each other, so that the height is 100/104 cm. For the weight, I put together all my standard bricks (I have 440 of them), and went to the grocery to weigh them. Result is 2.44 lb, or 1.1 Kg. Dividing 1100 grams by 440 bricks gives 2.5 g per brick.