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• Electronics and programming

  Maximiliano Rojas • 06/08/2020 at 01:41 • 0 comments

  The servomotors are connected to an Arduino Pro Mini which one is connected to a computer (same for the cameras), to supply all the electronics an old pc power supply is used to provide 5 [V] and 10 [A] (approximately). To transfer information between the Arduino and the Processing program the firmata protocol is implemented (I just upload the one in the Arduino IDE examples).

  A scheme of the electronic's connection is presented in the next image:

  In the processing program, first the necessary libraries for the communication, some variables for storage the angles for the servos are declared as well:

  Then the window control size is set, the Arduino to control selected, and the pins configured:

  Because of the mouse position on the window configured above control the movements, only one thing can be control at the same time, so, to select what is controlled just one click is necessary:

  The functions that transform the mouse position into angles are, for the neck:

  For the eyes:

  For the eyebrows:

  For the mouth (jaw):

• Mechanics

  Maximiliano Rojas • 06/08/2020 at 01:31 • 0 comments

  The cad design is int the files section, the extension is .123d that belongs to 123d design, like the "father" of Fusion 360, so, you may be capable to open the cad in the last program. 

  The general goals for this design was:

  • It must has two cameras with good visibility.
  • Reuse some parts like servos and other things from old projects of the robotic laboratory .
  • It must be capable of make basics facial gestures (jaw, eye and eyebrows movements).
  • The hard must be anthropomorphic.

  For the eyes movements two servomotors, gears and links are used, the idea is to accomplish two independent angular movements (up-down and left-right):

  So, for the left-right movements a gear is attached to the servo that move a gear attached to one eye, the other follows the movement through a link:

  For the up-down movement three gears with 1:1 relation were used:

  The neck can move in two different ways, the first one is up-down, this can be accomplish through two servos that move at the same time a worm gear where they torque applied is two times of the one of the servomotors, the other movement is left-right, it is done in a similar way, tow servomotors moving one thing. To "sense" when the mechanism is in it limit, buttons are placed in strategic part of the mechanism:

  For the mouth movement the jaw is driving by two servomotors through the simplest mechanism, two couple of gears with 1:1 relation:

  The eyebrows are moved by one servomotor each one, the joint is very straight forward:

  A general view of the place of the motors are presented in the next image:
  

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