Actuality and Artificiality

_{Stage Two: Week Commencing 21.10.2013}

_{Week (02)}

_{Description: The Aim of this session is to complete the mouth mechanism and test its durability.}

_Parts

_{Completed Upper and Lower Jaw from Stage 1}

_{2 x straight Meccano Bracket}

_{Phase 2.}

_{To attach the upper and lower jaw to the ‘Pan and tilt’ brackets on the servo a straight metal Meccano bracket was attached to the two L brackets on the corners on both the upper and lower jaw with nuts and bolts.}

_{The open source ‘Sweeping servo code was used from Arduino.cc.}

_{Example: (http://arduino.cc/en/Tutorial/sweep)}

 // Sweep

// This example code is in the public domain.

#include <Servo.h>

Servo myservo;  // create servo object to control a servo

                // a maximum of eight servo objects can be created

int pos = 0;    // variable to store the servo position

void setup()

{

  myservo.attach(9);  // attaches the servo on pin 9 to the servo object

}

void loop()

{

  for(pos = 0; pos < 180; pos += 1)  // goes from 0 degrees to 180 degrees

  {                                  // in steps of 1 degree

    myservo.write(pos);              // tell servo to go to position in variable 'pos'

    delay(15);                       // waits 15ms for the servo to reach the position

  }

  for(pos = 180; pos>=1; pos-=1)     // goes from 180 degrees to 0 degrees

  {                                

    myservo.write(pos);              // tell servo to go to position in variable 'pos'

    delay(15);                       // waits 15ms for the servo to reach the position

  }

}

_{However since I am using a Sensor shield (V4) – (2.1) the code has to be altered slightly to allow me to output to Analog ports on the shield.}

_{#include <Servo.h>}

_{long rfac;}

_{long mpos;}

_{Servo myservo;  // create servo object to control a servo}

                _{// a maximum of eight servo objects can be created}

_{long p=180;  //Starting Pos}

  _{void setup()}

_{

   _{Serial.begin(9600);}

  

  _{pinMode(A0,OUTPUT); //Output to analog (A0)}

  _{myservo.attach(A0);  // attaches the servo on pin A0 to the servo object}

_}

 _{void loop(){}

   _{myservo.write(p); //Write Pos}

   _{delay(100); //Adds a delay of 100 milliseconds}

  _{p=p+70; // Sweeps  position + inclination of 70}

   _{Serial.println(p); // prints pos in viewer}

 _}

_{Using this code I can test the starting and finishing position of the servo arm, this will give me a set of co-ordinates to work within and also help reduce stress on the gears of the servo. Using the sweeping method tests the durability of the build and also the torque and speed capabilities of the metal-geared servo. ( 2.2, ‘Video’)}

_Feelings:

_{I feel pleased with how the parts have come together and the successes of the initial testing, but I am disheartened having to alter the build to include additional elements I feel I have to backtrack slightly and look at a new approach for the jaw mechanism.}  

_Evaluation:

_{A key positive element of this session was that when the jaw components where positioned into place they fitted perfectly and looked aesthetically correct. However I feel that there may be future issues regarding the amount of torque placed on the Milliput from the servo (8kg) and also that a simple up and down movement for the jaw might not look as realistic as I initially envisaged. A possible second servo to control left and right jaw movement may be required to give the jaw a swinging action.}

_Analysis

_{The current situation of the build may have to be altered to make it more realistic and give more fluidity when it comes to matching it with audio output. It would make sense to scrap the original plans for the jaw mechanism and start over again implementing a second servo. However the adapted ‘Sweeping Servo’ code can be changed to add an additional servo into another Analog port to control the left and right movement of the jaw.}

_Conclusion

_{In conclusion I think I have done a lot of work on the project this week however I feel that a lot of time has been wasted due to poor planning concerning the un-natural behaviour of the jaw movement.}

_{Action Plan}

_{I will draw up a new sketch and incorporate a second servo into the plans to give me the left and right jaw movement, I will also adopt a more comprehensive approach to designing future frameworks of specific elements in order to help time management.}

1.1

1.2