Introduction and issues

[Oxac]

Hey guys, my name's Olle "AJ" Svenssons and here's my story.

I'm 18 years old, attending upper high (college in british english) and as my final project I will handwind pickups, market them, sell them etc.

I had mailing contact with Stan Hasley(?) and he directed me to this forum, where I've been lurking around for a couple of days and I've learned a lot and found really good some foundations for ideas to be built upon.

So what I need some help with is basically getting a little push in the right direction when it comes to information I need before starting out.

I'm going to get myself a sewing machine engine tomorrow and create my winder. So far no problems I guess. The problem would be the counter. I'm completely lost when it comes to counting the revolutions. I've reed about read switches and hooking them up to calc's and pedometers but frankly, I'm a bit lost.

Thank you for reading and any help or tip is very appreciated.

"AJ"

[Peter Naglitsch]

Hej AJ

Trevligt med en svensk till har pa forument. Valkommen.

It isn't as tricky as it might seem to do this. Where in Sweden are you? I might be able to lend a helping hand. The thing with calculators and pedometers is that a simple mechanical switch 8micro switches, reed switches) will bounce. It will not be obvious when looking at it, but hooked to an oscilloscope it will be obvious. A micro switch will bounce up to 5-6 times. This can be solver with a de-bouncing circuit that filters the bounces. The problem is that if you wind fast the next ?real? impulse from the switch might be filtered away, meaning you cannot go very fast. That?s why I prefer an industrial type proximity switch. I use an inductive switch that sense a screw embedded into my MDF faceplate.

When you have the switch business sorted out, the easiest way to go is a pedometer. Take it apart and you will find a mechanical device that bumps up and down with every step. Somewhere in there you should be able to find an electrical contact that you can solder the switch to.

The thing is: Is it really worth the hustle? A simple battery operated counter costs under 500 Swedish crowns from ELFA http://www.elfa.se/elfa-bin/setpage....&dok=12660.htm ELFA also have proximity switches and Hall Effect sensors that *should* be able to connect to that counter. It might even be possible that I have some stuff laying around that might be of some use.

[Oxac]

Thank you

Hi Peter, I'm from Halmstad (approximately 140 km south of Gothenburg). Thank you a lot for that info, really appreciate it.

I'll have a look at the link you gave me and we'll see what I can come up with!

Once again, thank you.

-edit- I'm a little bit confused about that inductive switch. I couldn't find one at the ELFA homepage, could you link me one please?

-2edit- would something like this work?
https://www1.elfa.se/elfa~se_sv/b2b/...wserminor=9.22

"AJ"

[Peter Naglitsch]

The link doesn't work for me. look for something like this:
http://www.elfa.se/elfa-bin/setpage....dok=130345.htm
Looking at them together I'm suddenly not 100% sure they will work together. It might be so that the K?bler counter needs a mechanical switch and that it will not work with a PNP output like that inductive proximity sensor (induktivgivare in Swedish). You will have to ask ELFA. If they don?t work together they might be able to suggest another counter that match your sensor or vice verse.

[Joe Gwinn]

The thing with calculators and pedometers is that a simple mechanical switch 8micro switches, reed switches) will bounce. It will not be obvious when looking at it, but hooked to an oscilloscope it will be obvious. A micro switch will bounce up to 5-6 times. This can be solved with a de-bouncing circuit that filters the bounces. The problem is that if you wind fast the next real impulse from the switch might be filtered away, meaning you cannot go very fast.

The trick is to put a small capacitor across the switch contacts, such that the time constant of voltage rise with the pullup resistor in the counter is around ten milliseconds. Then, the first connect will pull the voltage down, and it will be 10 mS after the last bounce before the voltage recovers. This will get you to 2000 or 3000 rpm.

That's why I prefer an industrial type proximity switch. I use an inductive switch that sense a screw embedded into my MDF faceplate.

I hadn't thought of this approach, on the theory that it was expensive and needed an added power source.

A simple battery operated counter costs under 500 Swedish crowns from ELFA http://www.elfa.se/elfa-bin/setpage....&dok=12660.htm ELFA also have proximity switches and Hall Effect sensors that *should* be able to connect to that counter.

I have a similar counter, a Red Lion CUB3.

I would search the archives. Various ways to do this have been discussed many times.

[Peter Naglitsch]

So a capacitor across the input takes care about the bounces. But will a mechanical switch handle 3000 RPM (=50 mechanical impulses per second)? Don?t think so. They are built for a few cycles per second, meaning maybe 200 rpm -> 25 minutes for ONE HB coil, almost an hour for a complete HB. And then you have the mechanical life and electrical life of an mechanical switch to consider. If I?m not misremembering a typical mechanical life of a high quality micro switch is 1-2000000 cycles. That will get you 100 to 200 Humbucker so that is of cause OK.

And yeah, an inductive switch might seem expensive, but I have fee access to them (a day job at a company that sells industrial automation equipment means some freebees) but they can be had for some 20-30 $ if you look at the right places. If you buy in bulk it will not cost more than 10$. All my equipment, brushless DC motor with integrated speed regulator, industrial counter and inductive switch, runs on 24 VDC so a power source is needed anyway. And we sell power supplies too?

[Steve Conner]

I'm sure if money is an issue, and brainpower isn't, you could do something with a permanent magnet and the Hall sensor chip from an old computer cooling fan.

http://forum.gobrushless.com/showthread.php?t=3733

[RedHouse]

I used an optical switch, like this:

http://users.isp.com/brad_anne/winder.htm#OPTEK

on that page you will also find a link to a PDF file I made up that shows how to integrate an optical switch to a CUB4 counter in case you want to try it..
(CUB4 counter modules come up all the time on eBay, you can get one for under $20 most of the time)

An electronics surplus place near me has (last time I looked) a drawer full of these Optek OPB380P switches for like $2/ea so I bought a few.

Allied has some newer ones:http://www.alliedelec.com/Search/Pro...x?SKU=387-0227
which would work just the same, might have to re-calculate the R1/R2 values in my PDF file though.

The OPB7xx series looks even simpler because you don't need any optical wheel, just some reflective tape or something, like maybe just paint the rear face of your bobbin mounting plate and put a single reflective strip on it.

[Joe Gwinn]

So a capacitor across the input takes care about the bounces. But will a mechanical switch handle 3000 RPM (=50 mechanical impulses per second)? Don't think so. They are built for a few cycles per second, meaning maybe 200 rpm -> 25 minutes for ONE HB coil, almost an hour for a complete HB. And then you have the mechanical life and electrical life of an mechanical switch to consider. If I'm not misremembering a typical mechanical life of a high quality micro switch is 1-2000000 cycles. That will get you 100 to 200 Humbucker so that is of cause OK.

Umm. A reed switch is easily able to open or close in a few milliseconds. A reed switch with capacitor (and series resistor to prevent contact welding) can control an electronic counter without added power. The problem is usually ensuring that the pulse length is long enough at max speed.

And yeah, an inductive switch might seem expensive, but I have free access to them (a day job at a company that sells industrial automation equipment means some freebees) but they can be had for some 20-30 $ if you look at the right places.

I have no idea what they go for around here.

If you buy in bulk it will not cost more than 10$.

I don't think that pickup makers will be buying these in bulk, at one or two winders per maker.

All my equipment, brushless DC motor with integrated speed regulator, industrial counter and inductive switch, runs on 24 VDC so a power source is needed anyway. And we sell power supplies too?

Ahh. With a brushless motor it ought to work OK. Brushed motors generate a lot of electrical noise, and independent supplies help a lot. As do hash filters.

[Oxac]

Thanks

Thanks for all of the great ideas and the great atmosphere. I'm still not sure how I will construct my counter, I'll start by modding my sewingmachine engine so I can wind the coils. Then we'll see how it goes.

So, would an inductive switch work for a sewingmachine engine?

[Joe Gwinn]

Thanks for all of the great ideas and the great atmosphere. I'm still not sure how I will construct my counter, I'll start by modding my sewing machine engine so I can wind the coils. Then we'll see how it goes.

So, would an inductive switch work for a sewing machine engine?

Industrial inductive switches are quite well shielded, and so won't be too sensitive to hash from the universal motor. But leave space for a shield around the motor and a hash filter in the power leads, in case you need to add these.