_{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

_{Stage one: Week Commencing 14.10.2013}

_{Week (01)}

_Description:

_{Today the rest of the parts I ordered arrived and I was able to start putting the initial mouth and eye mechanisms together.}

_Parts:

_{Metal U brackets x 6 – (1.1)}

_{Plastic ball and socket joints from an old lego toy - (1.2)}

_{2 x Eyes order from an American prop maker - (1.3)}

_{1 x L Bracket - (1.4)}

_{Bits of Mechano (4 x L brackets, 1 x Triangle Base)}

_{1 x Metal Gear Servo (MG996R) - (1.5)}

_{1x Prosthetic Teeth – (1.6)}

_{Milliput - (1.7)}

_{Phase 1.}

_Eyes

_{To start with I took the plastic Lego ball and socket joints and I trimmed off the parts that I did not need with cutters so that the socket could be placed into the back of the eyes and attached using Milliput. (The ball and socket joints are the same type I used in my second year final project, these joints where successful in giving a full range of eye movement). To make the element that would hold the rods for the eye movement I attached two aluminium standard U brackets back to back (These parts are usually used for ‘Pan and Tilt projects’, but the holes where perfectly places to run rods through - (1.8). I then attached the socket and ball joint together and using Milliput secured the eyes and the ball and socket joints onto the aluminium U bracket frame.}

_Mouth

_{Taking the prosthetic teeth and placing Milliput into the gum line, made it possible to attach the Meccano L brackets, when the Milliput had dried the Meccano Triangular base could be attached to the bottom jaw secured in place a screw and Milliput. To make the mechanism to control the mouth movement I attached a small Aluminium bracket to a servo using a tilt mount then on top on the mount I screwed in a L bracket with a U bracket attached to the side holes of the L bracket.}

_Feelings:

_{Although I was apprehensive concerning how the parts would fit together after I got going I felt that for the first session went really well, I am pleased with the quality of the parts that I have purchased and I am looking forward to the next session.}

_Evaluation:

_{The first stage of the build was successful, the parts fit together well and there was no need to repeat processes or dispose of any parts this reflects the quality of the components. However there are some concerns regarding the stability of the Milliput when placed under pressure from the servos.}

_Analysis:

_{The process of putting the initial parts together was made easy by using standard servo brackets and arranging them how I wanted using their pre-drilled holes, the lightweight aluminium also reduced weight and increased stability. Following the diagram and building on lessons learnt from the second year final project has helped make this first approach successful.}

_Conclusion:

_{In conclusion although the first stage of the build was a success the durability of the components and the Milliput holding them together will be tested as the project develops. (1.9)}

_{Action plan:}

_{The action plan for the second phase will be putting the jaw mechanism together to examine the durability of the parts; I will use the ‘Sweeping servo’ code from Arduino.cc to test this.}

_1.1

1.2

 1.3

1.4

1.5

1.6

1.7

 1.8

 1.9