New Guy's (Me) Contribution to Forum - Wind Counter

[jrdamien]

I am new. I have used this forum for all its amazing information. I put together a new winder with a hobby lathe and wanted to assemble a simple but accurate counter. My post about trying to figure this out is likely right below or a few posts below this one. But here's what I have for the sake of documenting it, should anyone else need a good, cheap solution.

Here's the counter:

12V 24V 6 Preset Digital Counter 10KPCS Relay 10 Off | eBay

$25 to $35 on the bay (I got mine on sale for $25). Not the cheapest or as cheap as a used cub (depending on the cub), but it's a preset, has 6 digits, counts up and down, is pnp and npn switchable, and has several other useful options.

This must be powered with a 12v wall wart. Wire the neg. and pos. directly to terminals 9 and 10. All necessary resistance is onboard.

To test it I first used a reed switch - that is, a door alarm. I wired one lead to terminal 1 (In) and the other to terminal 5 (OV). I put a single, small neo mag on the back of the face plate. I used the coil estimator to calculate 12k dc of 43 awg on a Tele bobbin, which gave me about 11k to 12.5k turns (an estimation - I forget the exact numbers). I wound to 11053 using variable speeds from 750 rpm to about 3000 and got a final resistance of 11.93. This tells me it was counting accurately.

I don't think I need a different sensor but had already ordered a proximity switch which just arrived. This is the one:

LJ12A3 4 Z AY Inductive Proximity Sensor Detection Switch PNP DC6 36V | eBay

With some help in the other thread I wired it black to terminal 1, brown to 4 and blue to 5. Nothing else required. I put aluminum tape across half a cd and mounted it behind the spindle with the switch mounted facing it and very close. This switch has to be almost touching it to switch. Again, absolutely precise counting up to as fast as the lathe will turn.

I'll post pics later. I hope this is helpful to anyone needing to assemble an accurate counting mechanism.

[jrdamien]

As an update (I will post pics tomorrow, I swear), I dumped the proximity sensor and went back to the door/window alarm reed. It is unquestionably more accurate. I tried a variety of different triggers for the proximity switch and tried different amounts of aluminum tape on a cd, but none of them did the trick. At higher rpms I could visually see the proximity switch was not tracking turns by the size of the coil.

If anyone knows why this might be please chime in, but for the sake of this being a tutorial, the reed switch works very well.

I also haven't given up on a few optical sensors I have but I've been too busy winding to tinker.

[David Schwab]

Try a small magnet to trip the proximity sensor. I have a bunch of those sensors. I haven't used them yet, but pickup maker Clint Searcy suggested I use them. He trips them with a small neo magnet. You could get a small disc magnet and attach it do your rotating CD.

[jrdamien]

Try a small magnet to trip the proximity sensor. I have a bunch of those sensors. I haven't used them yet, but pickup maker Clint Searcy suggested I use them. He trips them with a small neo magnet. You could get a small disc magnet and attach it do your rotating CD.

I actually use a small neo mag to trip the reed and it works perfectly. And while it does work with the proximity switch too (obviously), the accuracy is not as good as with the reed switch.

[David King]

That's clearly a superior reed switch you've got there. Where did it come from?

I tried a door/window switch and it never failed to bounce 2-5 times every turn. On the debounced counter input I was limited to about 600 RPM. TFPITA.

[jrdamien]

That's clearly a superior reed switch you've got there. Where did it come from?

I tried a door/window switch and it never failed to bounce 2-5 times every turn. On the debounced counter input I was limited to about 600 RPM. TFPITA.

I'd be willing to bet that it's more my inability to properly trigger the proximity sensor than it is the superiority of the reed switch, but you never know. I got it off ebay via Radioshack. It has these (mostly irrelevant) specs:

54-632 - Switch-Magnetic Reed Flange MNT #:54-632

This is an NTE magnetic alarm reed flange switch.
Mini stick−on surface-mount contact with side leads
Operate Gap 3/4" (19mm) min
Adhesive & screw mounting
Contact resistance: 150 milliohms
Switching voltage: 200 VDC max
Switching current: 500mA max
Insulation resistance: 10 gigohms
Shock resistance: 30G for 11mS
Vibration resistance: 20G (10 to 1000Hz)
Life expectancy: 20,000,000 cycles (resistive load, 12VDC, 250mA)

[kayakerca]

That's clearly a superior reed switch you've got there. Where did it come from?

I tried a door/window switch and it never failed to bounce 2-5 times every turn. On the debounced counter input I was limited to about 600 RPM. TFPITA.

I didn't use door/window reed switches, but I am using cheap little (vacuum bulb type) reed switches from China on my winder triggered by Neo magnets glued to the drive pulleys. I have checked them against a hand held laser tachometer and found them very accurate (~ .3 at 1,700 rpm) even at the very the top end of the drive motors' capacities. I also found that these reed switches worked best if they were not perpendicular to the direction of travel of the neo magnet.

[jrdamien]

After much delay...pictures! Hope it helps. And don't mock my use of tape. I live by this tape.







Oh, and the jig is just aluminum stock from any hardware store. It's thick enough to accommodate almost any pickup type. I have several drilled for use with different sorts of pickups that require reverse winding. Very simple setup.

[Steve Conner]

The inductive proximity sensors are meant to sense a protruding lump of ferrous metal such as a bolt head. I think they also work with a missing piece of ferrous metal, like a hole in the edge of a flywheel.

They're not supposed to work with aluminium tape or neo magnets.

[jrdamien]

The inductive proximity sensors are meant to sense a protruding lump of ferrous metal such as a bolt head. I think they also work with a missing piece of ferrous metal, like a hole in the edge of a flywheel.

They're not supposed to work with aluminium tape or neo magnets.

Well that would explain that. So, seeing my setup, how would you trigger it?

[ReWind]

Well that would explain that. So, seeing my setup, how would you trigger it?

You could machine and balance a faceplate of acrylic, instead of the aluminum/steel one on the lathe now, and use a slug of iron or similar in the faceplate to trigger it.

[Steve Conner]

I see a biggish round hole in the spindle just to the left of the faceplate, I would point the sensor at that and hope for the best. Actually I just noticed there are two holes, so you would get double counts, but maybe you can thread/glue a bolt or setscrew into one of them to get a protrusion. Or do likewise with one of the holes in the faceplate.

[jrdamien]

You could machine and balance a faceplate of acrylic, instead of the aluminum/steel one on the lathe now, and use a slug of iron or similar in the faceplate to trigger it.

Well I won't do that. The faceplate is too perfect and true to mess with. I'll try putting another cd behind it though with a slug attached to it...somehow.

[ReWind]

Doesn't that lathe have a minimum speed of close to 1000 RPMs? Watch out for wobble if you unbalance it with the weight of iron/steel slugs. I'd use as little mass as needed to trigger the sensor.

btw - It's a cool idea, what you've done there. I did something similar for hand winding with a lathe.

[ReWind]

Well I won't do that. The faceplate is too perfect and true to mess with. I'll try putting another cd behind it though with a slug attached to it...somehow.

If you machine the faceplate right on the winder/lathe itself (it's got the power!) it will be perfectly true to itself and the driveshaft by the nature of the process.