How to accurately control fan speed in rotations per second?
I am doing a science fair project in which I need to accurately control the fan speed of a small fan (1 to 6 inches in diameter), however I am unsure which fan to buy or how to control the fan speed accurately. I am not adverse to programing something as long as it is easy to do, as I am not a computer savvy...
-------------------------------------------------------
answers:
roderick_young say: Computer fans have a built-in tachometer, generally. There will be a red, black, and yellow wire. The yellow wire puts out one pulse every time the fan makes one revolution. It would not be hard for a (say) PICAXE processor to automatically control the fan speed to exactly what you want, but that would involve learning enough about electronics to hook it up. It's a $2 solution, but probably requires expertise beyond what you have.
A Raspberry Pi Zero would fit within your budget, and you could program it in Python, but it would still require quite a bit of learning to hook up. For this approach, or the previous one, be sure that you have an expert on hand to help you.
If you have access to electronic equipment, you can hook up a variable power supply to the fan and control it just by turning the voltage up or down. You could then sense the rotations with a frequency counter or oscilloscope, and manually adjust the power supply to get the RPM that you want. If you don't have a scope or frequency counter, you might be able to use your ears, if you have a musical ear. You can hook up headphones to the tachometer, and tune the voltage until the tone is neither flat nor sharp of a certain musical note. Then look up the frequency of the note on the internet. Or, if you can borrow an electronic tuner (people in band or who play guitar sometimes have them), that may be able to sense the frequency directly. There might even be an app for that, using your phone's microphone.
-
lee26loo，異域秦後人 say: WHAT TYPE OF MOTOR IS USED IN THIS SMALL FAN ?? DIFFERENT MOTOR HAS DIFFERENT WAY TO CONTROL ITS ROTATION SPEED !!
-
zhddr say: toyiaukg
-
ztznz say: ohnauyhk
-
ihjtq say: tbwzesjn
-
yhkwe say: aqiqzfja
-