Sewing Machine Coil Winder?

[salvarsan]

Thanks Dr.
I had to mess around to get it to trigger. I started with black sharpie and a white paper dot. The paper reflected less than the gloss black sharpie. I went with copper foil that I buffed up to mirror finish. The black was much trickier, I tried silicon carbide sandpaper but ended up with ebony dust sprinkled over wet shellac (can you tell I'm a luthier?).

That's instructive.

It means that the Sharpie ink transmits infra-red
in the band used by the optocoupler.

I got one to work with an aluminum foil patch on a black enameled
lathe faceplate, but we ultimately went with a Hall effect switch
for reasons I can't remember.

Oh, yes I do. (sigh)

I thought it would be clever to use a one-string guitar pickup type
as a turns counter. The first design had a steel screw head on the
radius of the masonite faceplate.

The sensor was a mere 200 winds of #42 on a 1inch nail with a neo
button magnet glued to the head, but turning that signal into a digital
one with a finicky comparator circuit was just too much trouble.

-drh

[RedHouse]

...
The sensor was a mere 200 winds of #42 on a 1inch nail with a neo
button magnet glued to the head, but turning that signal into a digital
one with a finicky comparator circuit was just too much trouble.

-drh

Did you try a "zero crossing detector" chip? those are just the ticket for this kind of thing, something like this should have done it for you:

http://www.national.com/mpf/LM/LM1815.html

[David King]

I think I finally figured out what was happening by measuring current flow or voltage drop across the phototransistor. When I slipped different reflective things in front of the sensor and varied the distance, I could figure out how it was supposed to work and get my counter to pay attention. Pulse width minimum I think was supposed to be 5 >ms or 5% dwell, I can't remember now, anyway it can count to 22khz I think.

[Joe Gwinn]

I think I finally figured out what was happening by measuring current flow or voltage drop across the phototransistor. When I slipped different reflective things in front of the sensor and varied the distance, I could figure out how it was supposed to work and get my counter to pay attention. Pulse width minimum I think was supposed to be 5 >ms or 5% dwell, I can't remember now, anyway it can count to 22khz I think.

The spec will most likely be for a minimum pulse width, and not for a dwell. The easy way to set this kind of thing up is to put a voltmeter across the phototransistor output and manually turn the bobbin shaft, thus measuring the fraction of a circle the output is high. Then some simple arithmetic will tell you how fast the bobbin can spin and still meet the minimum pulsewidth.

The 22 KHz will be with 50% duty cycle, which implies a 45 microsecond cycle and a 23 microsecond minimum width. That's awfully fast, and will allow the counter to respond to noise.

Hmm. I'd check if the 22 KHz is correct. If it's true, it's time for a resistor capacitor low-pass filter between phototransistor and counter, to prevent false counting.

[salvarsan]

Did you try a "zero crossing detector" chip?

Nope. We used an LM311 comparator with the circuit straight out of the National app notes.

When we saw how easy it was with a Hall effect switch (1 component, 3 wires), work on the variable reluctance sensor languished.

-drh

[RedHouse]

Nope. We used an LM311 comparator with the circuit straight out of the National app notes.

When we saw how easy it was with a Hall effect switch (1 component, 3 wires), work on the variable reluctance sensor languished.

-drh

Same here when I tried the pickup routine, then switched over to an optical interrupter and never looked back.

[clevenger-guitars]

Thanks

Here's my latest, another sewing machine spinner...



At the bottom of this page http://users.isp.com/brad_anne/winder.htm are a couple pics of the first coil wound with it, it took a few tries as I had to adjust things at first.

I built this one with an old Singer sewing machine motor I gutted out of a free machine, it was an old one from the 70's and wouldn't you know just when I got it finished and was ready to wind a pickup ...it gave up the ghost so I bought one of those generic replacement motors (made in chyna).

I used an optical sensor and light wheel similar to the Shatten setup, I used some decent bearings for a 3/8" shaft, and I wired-in a CUB4 counter module I got off eBay cheap cause the battery was going dead. These all run off a 12vDC 500mA supply built inside the winder.

I am going to build another one and give this one to my oldest friend, he has some medical issues and cannot work anymore. He loves music, sings and plays guitar, and I think he would like to wind pickups as he will get wheelchair-bound eventually.

Redhouse,

Great setup. While mine looks different from yours, I probably studied yours more than any other. I really like all the step-by-step pics on your website. Essentially, you showed me how to build a winder.

Thanks again,

Bert
Clevenger-Guitars

[RedHouse]

Redhouse,

Great setup. While mine looks different from yours, I probably studied yours more than any other. I really like all the step-by-step pics on your website. Essentially, you showed me how to build a winder.

Thanks again,

Bert
Clevenger-Guitars

Great, glad to be of help to someone here, that's exactly why I made that micro-blog. Take a pic and post it so I can see it 'eh?

My ISP will be going away in the very near future, so you might want to save the stuff you like from my site soon.

I am trying to get a domain host up-n-running for my business name and at that point I will put these pic on there, but I'm not sure I can edit all these posts links to reflect the new internet address.

[clevenger-guitars]

Great, glad to be of help to someone here, that's exactly why I made that micro-blog. Take a pic and post it so I can see it 'eh?

My ISP will be going away in the very near future, so you might want to save the stuff you like from my site soon.

I am trying to get a domain host up-n-running for my business name and at that point I will put these pic on there, but I'm not sure I can edit all these posts links to reflect the new internet address.

Redhouse,

I started a thread with a pic & a video link. It's here:

http://music-electronics-forum.com/s...t=%2425+winder

Thanks for the head's-up about your isp. I'll save those pics. Mine is a prototype, and I plan to build another. Your stuff was a great reference.

Bert
Clevenger-Guitars

[lexluthier72]

Hey Guys....Fast forward a little bit...I havent posted in a while. A buddy of mine offered me some good cash for my incomplete winder pictured earlier in this thread. Ive been so busy, I havent had time to try winding, well....now the time has come. I plan to build up another sewing machine winder. I finally found a mechanical counter! Now, the problem....how the heck does one mount it??? Its got a removable "arm" with a spring on it....Is there a pulley/wheel that can replace the arm/spring? Where should one mount the counter? Most of the photos I see the counter is optical....Any help would be appreciated. I'll post a photo of the sewing machine Im planning on using....its an oldie.
-Erin

[lexluthier72]

and whats the best way to drive the counter for most accurate results...?

[RedHouse]

Hey Guys....Fast forward a little bit...I havent posted in a while. A buddy of mine offered me some good cash for my incomplete winder pictured earlier in this thread. Ive been so busy, I havent had time to try winding, well....now the time has come. I plan to build up another sewing machine winder. I finally found a mechanical counter! Now, the problem....how the heck does one mount it??? Its got a removable "arm" with a spring on it....Is there a pulley/wheel that can replace the arm/spring? Where should one mount the counter? Most of the photos I see the counter is optical....Any help would be appreciated. I'll post a photo of the sewing machine Im planning on using....its an oldie.
-Erin

The kind of mechanincal counters with the arm & spring are usually not the kind that turn with a pulley/wheel.

You may have to rig-up something reminiscent of a train (steam locomotive) wheel where you have a arm attached to a wheel that pulls/pushes the arm on your counter.

Also be aware that mechanical counters often can't count very fast, you might want to test it to be sure it's actually counting correctly at the speed you want to wind.

[lexluthier72]

Edit:
Hmm....Looks like I'll be returning this counter! Doh. I think I will re-visit the calculator counter. Does anyone have experience with the calculator counter, as in how accurate is it? Or, Where can I find a cheep mechanical rotation counter? I found nothing on Ebay....

[lexluthier72]

Thoughts on sources of counters, or other counter methods would be appreciated. =)

[BizzarGuitars]

I have found that this computer program works for me.
This program allows you to "calculate pickup resistance, and number of winds based on bobbin dimensions and wire diameter. "
I only wind for my personal use, so take my suggestion with a grain of salt.

Ciao,

Garth