Making Toys

antisocial cat_ servo prototype

Prototype 005
Materials: PIC16F88, breadboard, servo, pot
Notes:
– The servo could keep turning left and right, but I couldn’t control its speed and directions.
– I found that Arduino has a servo library that is easy to use for controlling servos. So I decided to switch to Arduino board.

http://vimeo.com/moogaloop.swf?clip_id=2297781&server=vimeo.com&show_title=1&show_byline=1&show_portrait=0&color=&fullscreen=1
servo test from maze on Vimeo.

Prototype 006
Materials: Arduino, servo, breadboard, IR sensor
Notes:
– In the very beginning, the range of IR sensor was too small. Thus the servo only moved when I almost touched the sensor. Here I scaled the value of IR sensor from 0-1023 to 0-179.

– The servo had a problem of drawing too much current.

– So I did iteration by separating power supply for the servo, but joined the grounds of the two power supplies. I also added decoupling capacitors to stabilize my voltage regulator.

http://vimeo.com/moogaloop.swf?clip_id=2391917&server=vimeo.com&show_title=1&show_byline=1&show_portrait=0&color=&fullscreen=1
prototype_arduino+servo+ir sensor from maze on Vimeo.

– Here is the code:
——————————————————————————————————–
#include <Servo.h>

Servo myservo; //create servo object to control a servo
int sensor = 0;  // analog pin used to connect the sensor
int motorPin=11;
int val;    // variable to read the value from the analog pin

void setup()
{
  myservo.attach(11);
  myservo.setMaximumPulse(2200);
 
  Serial.begin(9600);           // set up Serial library at 9600 bps
  pinMode(sensor, INPUT);
  //pinMode(relay, OUTPUT);
  pinMode(motorPin, OUTPUT);
  myservo.setMaximumPulse(2000);
  myservo.setMinimumPulse(700);

  Serial.print("Ready\n");
}

int getSensor() {
  val = analogRead(sensor);            // reads the value of the potentiometer (value between 0 and 1023)
  val = map(val, 0, 1023, 0, 179);     // scale it to use it with the servo (value between 0 and 180)

  val=max(val,5);
  val=min(val,180);

  return val;
} //end of getSensor

/*
int moveFoward() {
  analogWrite(motorPin, getSensor());
  delay(1000);
  digitalWrite(motorPin, LOW);
  delay(1000);
  //digitalWrite(relay, HIGH);
  //Serial.println(getIR());
  delay(1000);
}

int moveBackward() {
  analogWrite(motorPin, getSensor());
  delay(1000);
  digitalWrite(motorPin, LOW);
  delay(1000);
  //digitalWrite(relay, LOW);
  //Serial.println(getIR());
  delay(1000);
}
*/

void loop()
{
/*
    val=getSensor();
    if (val<140){
        val=180;
        myservo.write(val);                  // sets the servo position according to the scaled value
        delay(15);                           // waits for the servo to get there
    }//end of if

  while(getSensor()>30){
    myservo.write(getSensor());
    Serial.println(getSensor());
    delay(15);
  }//end of while
*/
    myservo.write(getSensor());
    Serial.println(getSensor());
    delay(15);

  //moveFoward();
  //moveBackward();
  Servo::refresh();
}
————————————————————————————————-
– I tried to pause the servo after every time it turns by expanding the delay time of myservo.write(). However, its movement became unpredictable. Then I tried moveFoward() and moveBackward() above, but they didn’t work well either.
– Another problem I have is the click sound of servo. I was wondering if extreme turning angles like 179 or 180 caused those noise.