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I am 14 I have always wanted to build a cnc machine but because inexpensive parts are hard to find in Canada I have had trouble trying to build a decent cnc controller. The purpose if this Instructable is to show that anyone can build a cnc controller using an old scanner. The scanner I used was an old OpticPro scanner. I had previously extracted the stepper motor and experimented with it but not considered it for a cnc controller. All of the controllers on the Internet had a large number of expensive transistors or were ridiculously complex. I finally stumbled across this
controller and realized I could build it. By reusing the parts from the old scanner and making the case from recycled cardboard, I am cutting back on my impact on the planet. Also, because this controller is so simple, it only needs one power suply, so, it only needs 1 12 volt (for both the logic and the motors), instead of 1 5volt (for the logic) and 1 12 volt (for the motors). This saves energy, especially when you run it for a long period of time.
If you don't already know what a cnc machine is, it is a machine that uses special motors called stepper motors to moce an object a percise distance. The difference between a stepper motor and a regular DC motor, is that stepper motors "Step", not spin. if you don't understand, refer to this
artical. There are two types of stepper motors. There is Bipolar, and Unipolar. Bipolar motors have 4 wires. Unipolar motors can have 5, 6 and 8 wires. The difference between these two types of motors is that unipolar motors have 4 coil inside that, when energized in a certain order, allow it to step forward and backwards. This makes them easy to control and is why we are going to use them in this instructable. Bipolar motors only have two coils that can be energized in forward, or reverse. To drive a bipolar motor you need two H-bridges. Because of this, bipolar motors motor controllers are much more complex.