Phase 2: Medium Setup

The second display was intended to show that the Arduino could drive a high amperage motor.  The drill motor draws about 3A, which is significantly higher than what the Arduino can handle.  As a result, we added some external circuitry to control the high-amp circuit.

  • Amping up to DC
    • Arduino signal must be put through a transistor
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Tip 120 Transistor

      • Be careful, they get hot.
      • Make sure things are wired properly, if not they will catch on fire
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Melted Bread Board

    • Transistors can only control the motor in one direction.  To drive the motor both ways, we needed an H-bridge. Larger setup
    • This setup was designed to use a high-amp drill motor.

 

H-Bridge with Tip 120: http://trandi.wordpress.com/2011/04/20/my-first-h-bridge/

Slide2

H-Bridge Clock Wise

 

Slide1

H-Bridge CounterClockwise

  • Arduino control
    • The motor is connected to pins 5 and 7 on the Arduino.
      • To run motor forwards, set pin 5 on HIGH and pin 7 on LOW.
      • To run backwards, 5 LOW 7 HIGH
      • To turn off, set both LOW.
      • NEVER HAVE BOTH PINS ON AT THE SAME TIME!!!!!!!!!!
    • Do not need to give it specific position control – just tell it to go forward or backwards.
    • The motor may run too fast for your setup.  To control the amount of power sent to the motor, change the number in the “analogWrite funciton.”
    • Analog Write
      • The program will take a number between 0 and 255 – 0 is the lowest voltage and 255 is the highest.
    • For safety reasons, we added limit switches.  If the motor turns too far, it will hit the switch and send a signal to the Arduino.

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