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Author Topic: Testing Motor Shield with CPU fan motors?  (Read 1789 times)
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Is there anything against testing the arduino motor shield with CPU fans?  Reversing the polarity on the direction pin would cause my fan to spin backwards, right?  Could the reverse spinning hurt this type of motor?  Would the breaking feature work on these motors?

I have 2 computer CPU fans:
1 DC fan 12V, 2.1 watt, 0.18amp with only 2 wires (red, black)
1 DC Brushless 12V, 1.7watt, 0.14amp with 3 wires (red, black, yellow)

What is the yellow wire for?  Thanks. smiley-roll-blue
« Last Edit: December 04, 2012, 07:54:01 pm by encryptor » Logged

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Is there anything against testing the arduino motor shield with CPU fans?  Reversing the polarity on the direction pin would cause my fan to spin backwards, right?  Could the reverse spinning hurt this type of motor?  Would the breaking feature work on these motors?

I have 2 computer CPU fans:
1 DC fan 12V, 2.1 watt, 0.18amp with only 2 wires (red, black)
1 DC Brushless 12V, 1.7watt, 0.14amp with 2 wires (red, black, yellow)

What is the yellow wire for?
I think it sends pulses out when the motor is turning so it can be used as a safety feedback signal, as in "I'm telling the motor to turn but I'm not receiving any pulses back from it" error detection method.
Lefty


  Thanks. smiley-roll-blue
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Are they safe to use with the motor shield?  Does the reverse direction hurt this type of motor.  Or otherwise said, how can I tell if these motors are bi-directional? Can someone confirm retrolefty's last statement about the yelllow wire?  Does anyone use this in their projects?smiley-mr-green
« Last Edit: December 04, 2012, 07:59:59 pm by encryptor » Logged

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Are they safe to use with the motor shield?  Does the reverse direction hurt this type of motor.  Or otherwise said, how can I tell if these motors are bi-directional? Can someone confirm the last statement about the yelllow wire?  Does anyone use this in their projects?smiley-mr-green

Well most DC motors are bidirectional unless they have an internal diode across the motor terminals to suppress transients when turning off the motor (test with a multimeter for equal resistance with both polarities or use the diode test if your meter has one), however the fan air flow may only be optimum in one direction. So just buy a real cheap PC fan from E-bay or play with one from a Junker PC and see what you can do with it. A H-drive rated at 12volt or higher and a amp or higher should be fine I would think. Or do you expect some kind of guarantee that anything you try and do to the motor will be fine and not put your eye out?  smiley-wink

Lefty
« Last Edit: December 04, 2012, 08:07:12 pm by retrolefty » Logged

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Now that you mention it, what is the H-drive?  What is a H - Bridge? smiley-zipper
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PC fans rotate in one direction only; they are essentially BLDC motors with the controller built into the motor itself. The coils are fixed on a small PCB (which also has the driver circuitry on it), and the fan hub has a round, polarized ring magnet that fits around the coils and spins. If you reverse the polarity of the input voltage on the fan, it will just sit there (and if the fan is cheap enough, the magic smoke will be released). The only thing you can do with these fans is (in general) turn them on or off (using a relay or transistor), and you can vary the speed of the fan by varying the voltage (PWM or otherwise), within a certain limit (you should not exceed the rated voltage to try to make such a fan spin faster, as you will likely burn out the control electronics; you can however apply lower voltages down to a certain limit to make it spin slower).
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Now that you mention it, what is the H-drive?  What is a H - Bridge? smiley-zipper

It's a circuit designed to power and control a motor so that it can be commanded to turn in either direction and at variable speed. It's an interface shield board or module that wires between an arduino controller and the higher voltage and current motor and it's power source.

Lefty
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for my cpu fan that just has red and black wires, which pin(s) would I plug them into?  How do I access the screw terminal ports?  I only see the function Stepper myStepper(stepsPerRevolution, 8,9) for this two wire example. 
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All I read is:

Stepper(steps, pin1, pin2)

Parameters

steps: the number of steps in one revolution of your motor. If your motor gives the number of degrees per step, divide that number into 360 to get the number of steps (e.g. 360 / 3.6 gives 100 steps). (int)

pin1, pin2: two pins that are attached to the motor (int)
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as far as i know, a pc fan only rotate in one direction, using a H Bridge would be a waste. Just use a transistor or a mosfet to control your pc fan. Just use the analogWrite to control the motor speed. Btw pc fan is not a stepper motor.
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