Thursday 21 November 2013

Arduino Starter Kit - Chapter 09 and 10




It's been a long time since my last post, I'm sorry I've be very busy in these weeks.
Trying to restart the Arduino Starter Kit explanation, today I'll explain what you can find in the chapter 9 and 10 of the manual.

09 MOTORIZED PINWHEEL a color wheel that will have your head spinning
10 ZOETROPE create a mechanical animation you can play forward or reverse

Both of this chapter do not add anything new to the code side, in fact both project are pretty similar to the code used for turning on a led.

Chapter 09:
In this chapter we'll use a motor, a mosfet and a diode.

Motors typically require more current than the Arduino can provide. The Arduino can only provide 40mA from it's digital pins, much less than required to a motor to work.
So we'll use an external 9v battery.

A  mosfet is a transistor, and they are components that allow you to controll high current or voltage power sources from the current output of the Arduino. A transistor is in fact a digital switch: when you provide voltage to the gate pin it close the circuit between the other two pins (source and drain).

A motor is a type of inductive device. Induction is a process by which a changing electrical current in a wire can generate a changing magnetic field around the wire. When a motor is given electricity a tightly wound coil create a magnetic field which cause the shaft to spin around.

To protect the transistor from the back-voltage generated from the inertia of the motor you should put a diode in parallel with the motor. The diode allow electricity to flow in one direction protecting the rest of the circuit.



Chapter 10:
Based on the previous chapter, here you use an H-Bridge to reverse the polarity of the motor.
An H-Bridge is a type of component know as Integrated Circuit that has a lot of transistor built in.





Since there is no new code to explain in both chapter for today is over, hope to post the next chapter a little earlier than the last time.

Ygy Freezone

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