ICT: SERVO MOTORS

• Servo Motor


  A motor that allows you to precisely control physical movement because they generally move to a position rather than continuously rotating

  
• Servos


  • They are simple to connect and control because the motor driver is built right into them
• Servo motor

  Contains a small DC motor connected to the output shaft through gears. The output shaft drives a servo horn and is also linked to a potentiometer (pot).
• How do Servo motors work?

  1. You can control the servo motor by sending a series of pulses to it

  2. A typical servo motor expects a pulse every 20 milliseconds (i.e., the signal should be 50Hz)

  3. The length of the pulse determines the position of the servo motor

  
• Pulse duration

  • A short pulse of 1 ms or less will rotate the servo to 0 degrees (one extreme)
  • A pulse duration of 1.5 ms will rotate the servo to 90 degrees (middle position)
  • A pulse duration of 2 ms or so will rotate the servo to 180 degrees (other extreme)
  • Pulses ranging from 1ms to 2ms will rotate the servo to a position proportional to the pulse width
• SG90 Micro Servo Motor


  • Operates on 4.8-6VDC (5V typical) and can rotate 180 degrees (90 in each direction)
  • Draws about 10mA when idle and 100mA to 250mA when moving, so we can power it with the Arduino's 5-volt output

  
• If your servo consumes more than 250mA, consider using a separate power supply for it
• Arduino Sketch

  1. Go to File > Examples > Servo

  2. You will see two sketches, namely, Knob and Sweep

  3. Select one and upload to your board and use it to see what it can do
• SERVO MOTOR PARTS

  • Servo Horn
  • Gear Train
  • Potentiometer
  • DC Motor
  • Control Unit
• SERVO MOTOR PINOUT

  1. GND
  2. 5V
  3. Control