Firky2010

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LEGO Facts

  • LEGO is an abbreviation of the two Danish words "leg godt", meaning "play well"
  • During the moulding process, the plastic is heated to 232°C until its consistency is that of dough
  • In 2003 LEGO  changed the minifigure's yellow facial colouring to a more authentic skin colour
  • In 2006 the LEGO  website had an average of 8,137,062 individual visitors a month
  • If you built a column of about 40,000,000,000 LEGO bricks, it would reach the moon

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759days since
Project Launch
Welcome to my LEGO robotic arm project!

Since January the 5th 2010 I have been building my robotic Arm. I started building my arm from LEGO Technic and LEGO Mindstorms. I chose LEGO Technic for this project as it seemed a good starting point for me because it is readily available, easy to work with and it does not require any machining. LEGO also have good, easy to use software such as LEGO Digital Designer and Mindstorms NXT. I wanted to build this Robotic arm to learn about robotics and programming. This would also give me a chance to become a part of the LEGO NXT and Robotics communities, hopefully getting involved in more high tech robots and programming in the near future. I plan to use this site to show and share the progress of my Arm and hopefully build up some interest and help others achieve their goals.

Project Objectives:

Before I stared building my Arm I needed to know what I wanted to achieve, such as how my Arm would be controlled and what activities the arm would perform.
  • Stable and able to suport its own weight
  • 3 or more degrees of freedom including Pitch,Yaw and Roll
  • 360 degrees movement without cable limitations on base
  • 360 degrees grab movement for screwing and unscrewing nuts and bolts
  • A grab able to maintain a constant grip 
  • Remotely controlled using a joystick
  • Mindstorm NXT compatible
  • The ability to be programmed to build other less complicated lego models 

The Arm:

Here is a picture of the grab that I have been building my arm around over the last few months. I found this design at MOCpages.com the grab was designed by Eric Sophie. You can see it in action in the youtube videos on the right of this page. The Grab itself is one of the most important parts of this robotic Arm. Without the grab the Arm would have no purpose.  The grab is powered by two LEGO M-Motors, one for the open and close action and one for the 360 degree rotation. The pincers of the grab use LEGO Technic shock absorbers to help centralise the object being lifted and to provide a force able to maintain a strong grip once the motor has stopped running. 




After a while I found that building from the grab was not the best way ahead. Altho I need to build a grab to give the arm a purpose it also proved very difficult to work from the grab back to the shoulder as the arm grow it became to big and heavy to work with. Every joint needed to be geared down so the motors could lift the arm. The movements became very slow and I couldn't come up with a shoulder joint strong enough to support the arm let alone move it. Now I had an idea of how big the grab and fore arm could be 
 I set to work to find the strongest lego turn table. It turns out Lego Hailfire droids have two huge wheels that can be used to make a turn table. By placing about 45 lego footballs between two Hailfire droid wheels. Shown in this video by Searme. I have yet to see any thing any where near as reliable as this. 

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