Advance thanks for any help I can get here! I'm very new to Arduino but have been reading for years about all the amazing things they can do.
I'd like to build my wife a skein winder. What's that you ask? A skein winder spins to take up yarn off a spindle to create something called a skein (which is just a specific length of yarn).
Now for MY QUESTION: Can I use Arduino to count rotations of the winder and then stop the motor? This function would allow us to repeatedly make skeins of a consistent length.
I feel deep in my gut that someone out there has an answer or at least a direction to look. Any help would be greatly appreciated!
short question "can it be done"? Short answer "Yes".
Longer answer, one usually puts a magnet on the part that is turning (in your case, the wheel where the skein is being built onto). Then, you put a magnet sensor. This can be something called a Hall Effect or something like a magnetic reed Switch. Every time that magnet passes the sensor/Switch, it generates an Input to a digital Input pin on the Arduino.
Another Technology is to not use a "simple" DC Motor but something called a stepper Motor. They are more expensive but the Arduino can tell them to take a step. Often it takes 200 such steps to equal one Rotation so the Arduino is in very fine control of how fast/often the device spins.
Whether you use a simple DC Motor or a stepper Motor, you can't power it directly from the Arduino. The Arduino Pins can only supply 20 mA of power. You will Need a Transistor or MOSFET or (for a stepper) a Controller to do that.
Using the key words from my answer, you will find thousands of suggestions on the Forum on how to proceed.
Alternatives to a magnet and a hall-effect sensor are ...
a slotted optical switch in which a tag on the shaft breaks the beam within the switch
or
a reflective optical switch which just needs a blob of white paint on the shaft. If you need to count half revolutions you could use 2 blobs of white paint.
A more sophisticated solution would be a rotary encoder but they are more difficult to program for and would really only make sense if you need control over fractional revolutions.
I also suspect a stepper motor would be overkill for this application and a simple geared DC motor would be sufficient. I presume the skein will not be rotating fast.
