I am in the process of building a guitar pickup winder and have a few issues with designing a traverse mechanism to guiide the pickup wire onto the pickup as it spins.
I need the ability to have a guide which automatically moves from left to right for a given distance - anything from 10mm to not over 20mm and at speeds of no more than 1 cycle per second (adjustable speed and adjustable distance)
I am looking at a linear stepper motor and linear guide rail - my issue is with controllers - I dont want to hook up a PC just to control this motion - looking at controller boards they have the small switches to adjust the stepper amounts - would this suffice?
Thanks to anyone in advance who can help me with this - I just hope I am not wasting time on a design idea that wont work.
Controlling a stepper driver to do a fixed task like that isnt difficult, just need to be clearer on your requirements. Some controllers have limited stand-alone capability but i doubt they'll be flexible enough for your needs.
If I understand your requirement you want to program the number of steps (distance) and the rate of traverse (steps per second) and have this cycle back and forth (step direction) as the pickup bobbin rotates presumably. I guess the traverse is linked to bobbin rotation, ie 1 traverse = 1 rotation? How do you plan to do that synchronisation?
Happy to help with design of a suitable solution.
Basically the pickup winder will have 2 motors - 1 will run the fixed position spinning pickup bobbin, the 2nd motor will run the feed for the pickup wire (think of a sewing machine winding a bobbin with cotton thread) this 2nd motor / mechanism needs to move from side to side as it feeds the pickup wire onto the spinning bobbin. The problem is that each pickup bobbin style has different widths so the feed mechanism needs to be adjustable to accommodate the various sizes - from about 10mm wide to a maximum of about 20mm wide. The motors don't need to be in synch with each other.
The control I need for motor 1 is just speed (from 0 to a max of about 1500 rpm) and direction (so I can wind clockwise and counter clockwise) - I was going to use a basic 12v Dc motor with a max rpm within my range, controlled via a PWM and reverse wiring to change spin direction via a switch.
Motor 2 is the tricky one as I need control of the speed - max of about 250 rpm and obviously control of the distance it actually moves the feed. The start position of the feed will be the same for each pickup, it's the distance of travel that will vary.
I have been looking at various stepper / DC motor controllers but they all seem to need a Pc to run them. Another option is the raspberry pi / micro pc route with attached controller and lcd display which I think would provide the options I need but am not sure about the ease of use in an everyday situation. If needs be, I ,ay have to add a Pc for functionality but it seems a bit overkill for my needs.
Last edited by timellis; 22-08-2013 at 04:23 PM.
OK so motor 1 controls the number of turns of wire on the bobbin? How will you determine when and how to stop winding?
If I read right, motor two moves the feed point back and forth? If not synced to the bobbin rotation you're going for random fill rather than side-by-side winding . Are you sure thats what you want? I assume therefore you never fill the bobbin completely. (never done guitar pickups but many years back built a coil winder for amateur radio equipment, transformers, etc. so principle is similar)
I guess the wire feed spool is lightly braked to maintain tension in the (fine gauge?) wire.
22-08-2013 #5Visit Us: www.zappautomation.com
Yes, motor 1 has a counter (reed switch) to determin the number of winds.
Motor 2 is going to random fill the bobbin although some kind of synced method may be worth looking in to. The feed spool has a slight tension as you noted.
I have been looking at some of the Ardunio based Setup's and they look very interesting.
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