the drawing arm

Discussion in 'The Projects Forum' started by MegaMan, Feb 18, 2010.

  1. MegaMan

    Thread Starter Member

    Sep 25, 2009
    hello forums , thanks for helping newbies , it was always so nice of you ...

    i'm a 3rd year mechatronics engineering student
    thinking of making a drawing arm

    but not from a lego kit , i want to do it from scratch ...
    any tips ? ,

    i.e. is making it a hanging arm better ?
    etc etc ..

    please help me .
  2. beenthere

    Retired Moderator

    Apr 20, 2004
  3. MegaMan

    Thread Starter Member

    Sep 25, 2009
  4. BMorse

    AAC Fanatic!

    Sep 26, 2009

    I guess the first you need to figure out is how big of a drawing do you want it to be capable of drawing (i.e. 8 1/2" x 11", A4 size, etc.)

    Try to use the most lightweight but rigid material you can find to make the "Arm" extensions, and use either stepper motors or hobby servos to control each joint,

    there are 4 popular types of robotic "arms", a Polar Coordinate Arm, a Revolute Coordinate Arm, Cylindrical Coordinate or a Cartesian Coordinate....

    For what you want to do a Revolute would be the best suited for your needs, since this is modeled after the Human Arm so it could have many of the same capabilities, a typical design is somewhat different than the human arm because of the complexity of the shoulder joint.

    And since this is just for drawing, I would suggest using RC servos (or Hobby Servos as they are referred to sometimes)... since these already have the controlling circuits for the motors and all you have to do is provide power and the proper pulse width to move them left or right (same motors used in the second video you posted.)

    My .02