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Breaking away from my Spyder build thread to ask some advice of those of you who modify electronic things and such. As explained elsewhere, I'm beefing up my bead roller a bit and looking to motorize it with an old power winch.

This winch seems just right. I don't know the reduction ratio but it has three massive thousand-tooth step-down gears in it, the second one of which runs the hand shaft.

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That's probably the way to turn the roller but if it's too fast or not enough torque there's a teeny tiny, heavy duty gear on the inside of it that spins the third big gear on the other side of the device, and that's what drives the actual winching mechanism. So I figure I've got two really good shots of this working nice as a direct drive for the roller.

I still have to figure out how to couple it, but that's for later.

Right now my questions are two: First, which power supply would be best to step it down to 12 volt DC from 120 AC? I have on hand both an old ATX computer power supply, which I understand can be modded for this application, and the control boards from the tread mill I took apart years ago for a now-abandoned potter's wheel project for my wife.

That thing ran two electric motors—a big honkin' one that I hope some day to incorporate into something cool, and a much smaller one that raised and lowered the front of the machine. This was all controlled via an LED panel with soft buttons.

Here's the back of that panel:

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One of the controls on that panel is for the treadmill speed. There are two arrows pointing different directions and of you press one it goes a little faster; the other a little slower. The feed from it comes out that ethernet looking thing and plugs into...

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This likely looking bit of kit. Pretty sure that's my AC/DC converter, judging by the wires going in and out of it.

What I want to do here is to incorporate a potentiometer that's controlled by a foot pedal, as for a sewing machine. I have a feeling that this could be done on a low-voltage/low amperage basis with this thing—as that seems to be what's happening with the stock controller and it's teeny little wires!

But...how?

Here's a better shot of that (presumed) power board. I notice it has several sets of pin-outs that look like they're made to take different kinds of controller inputs.

IMG_6872

Can anyone here help me understand what I have here and where I might find (or how I might go about making) a compatible component?

I know if all else fails I can always rig it up to move at one slow speed and put a headlight dimmer switch on a piece of wood on the floor to turn it on and off with my foot. But a real speed control pedal would be so much neater!

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Last edited by edsnova
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Before you do anything else, you need to know what voltage and current draw this winch motor requires. And we're not talking about no-load running, we're talking about how much current it draws under full load, preferably not locked/not turning.

I run my trailer winch off of a small deep-cycle battery(U1 lawn tractor size). That would be your best bet, IMHO, rather than AC to DC adapter. Any old car battery will do.

What gauge are the wires feeding the winch? That will tell you the approximate current draw. My winch has 8 gauge, which will handle up to 50 amps.

10 gauge is for 30 amps, 12 gauge is 20, and 14 gauge will take 15 amps, usually.

Last edited by DannyP

Here's the motor, Danny.

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It's kind of a toy—about the size of the little lifting motor on the treadmill. Those wires might be 10s but I think they're 12s. So maybe 30 amps? No way it's drawing more than the treadmill motor, which is bigger than the motor on my compressor and weighs about 50 pounds. That's why I like the treadmill controllers.

I know I can just rig it to a battery but I don't happen to have a spare car battery just now and also I think it'd be a lot neater to just plug it in....

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OK, so you need to pull out the AC to DC converter/power supply from the treadmill. Judging by that relay with a 12v coil, the treadmill would seem to output 12v DC. Verify with a voltmeter first!

Then find yourself a 12v speed controller that can handle at least 20 amps controlled by a potentiometer/rheostat in a foot pedal. I'm sure you could find an old sewing machine foot pedal somewhere.

And I'm thinking that, most likely, the voltage conversion/control is also using pulse width modulation (PWM) to control the speed of the motor.  That means that the controller is sending out a series of pulses to the motor at 12 volts each, but the pulses are shorter and farther apart at slow speeds, then get longer and closer together at higher speeds.

Hot Rod Ron, my friend with the '34 Dodge street rod, used to do this stuff for a living for Norton Abrasives.  He was one of their production line engineers for, like, ever.  I'll send him the link to this thread and see what he comes up with.

Talked to Ron but he lost the neutral on the power coming into his house during the last storm and smoked his internet connection along with all of his appliances.  Sounded just like what we went through with the generator, last summer - lots of weird stuff got smoked.

Anyway, he'll be back on in a day or so and check in.  In the meantime, he said:

  1. Is the motor you want to use AC or DC and what voltage?  If you want to use the boat winch motor you know that it's a 12V motor, but if you want to use the tread motor from the treadmill you'll have to check the label on it to see what it wants.
  2. Do you ever want to run it in reverse?  (might be handy if the work piece gets stuck and you want to back out of it.)  The treadmill motor (if it's AC) might not like to do that.
  3. A friend of ours is using those treadmill motors in electric wheelchairs - They are rated for continuous use, have lots of torque and respond well to different controller types.  That also implies that they can run backwards so they might be DC (or have a separate phase winding inside to run backwards - we don't know). We'll try to get him (Charlie) in the loop, too, for what he uses for variable input controllers on the wheel chairs.

He mentioned a bunch of other stuff to ask about but it was over my pay grade - I only used to make little sparks - like under 5 volts was my world.  Ron dealt in stuff that makes BIG sparks.

Ron also mentioned a web site for automotive electrical stuff that he uses a lot and I had never heard of, so here's one more source for interesting parts.  Their web site is good but slightly non-intuitive so just click on the list icon left of the yellow '40 Austin coupe at the top of the page for the full menu.  "Watson's Street Works"

https://watsons-streetworks.com/home-mobile/

Last edited by Gordon Nichols

@Gordon Nichols:  I want to use the winch motor which is 12v DC. The treadmill is also 12 DC, as I recall from my adventures building a potter's wheel 3/4 of the way to completion. I had the controllers pictured running the big treadmill motor, with all the safety features still on line (instant-off pull-off, overload fuse, etc.). Will double-check that output.

Yes, the treadmill motor is too much for this job. The winch motor is probably perfect. And Yes I want it to be able to reverse. That feature may (or may not) be incorporated into the winch gearbox. Will investigate.

@DannyP I figure an in-line pedal would be the easiest to wire but maybe the hardest to find and most expensive? I've seen some sewing machine pedals on-line and the wires coming off those are like 12 or 14 gauge. That's the main reason I want to use this converter board: it looks like it wants to have a low-amp, low volt modulator tell it how to control speed.

The treadmill had a reverse feature as well, so I figure that's available. Heck, I could probably just use the whole existing treadmill rig. But:

I just don't want to have to mount this whole big goofy treadmill dashboard up next to my bead roller.

"I just don't want to have to mount this whole big goofy treadmill dashboard up next to my bead roller."

I hear yah.   Even the guys going to the International Space Station have gone from this, in the old shuttle:

Luna Module 1

To this, in the Space X Dragon:

Luna Module 2

At least they keep moving towards the screens on the Rocinante:

Luna Module 3

Using all of the control from the potter's wheel might be the way to go.  It looks like the treadmill had a soft console running a serial buss (5 wire flat cable) to the motor controller that did all of the conversions from digital to analog.  using as much of that as possible sounds like a lot less work than re-creating the proverbial wheel.

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Last edited by Gordon Nichols

AFAIK, electric winches using a 12v DC motor go forward and backwards.

Ed, I was not suggesting to wire the sewing machine pedal DIRECTLY, merely using it as an input device.

Gordon, no way for me to tell what protocol or how many wires were used on that flat wire, but it is definitely an RJ-45 connector, which is 8 conductors. And I've made up flat and Cat 3, 5, 6, and 6a cables for like eons.

Here's a look at the winch motor and gearbox after I pulled the cable out. There's no reverse but the clicker can come off easily.

I also pulled out all the old treadmill junk and lashed it all together to see if the controller still works.

It does.

So when I look online for foot pedals I get like this thing for sewing machines. Notice it's got a phono cable plug output.

  • Resistance: approx. 1KΩ - 20KΩ
  • Rated voltage: 15V DC
  • Rated current: 3mA max

This looks like the sort of thing that could integrate into my board... but how?

Most everything else I find has like a big AC plug pass-through system, like this.

I feel like that's a crude thing but maybe would work if I went with the computer power supply? It's an AC controller with a 4 amp rating.

Last edited by edsnova

Interesting.  

Let’s not over think this.  All you need is a cheap, PWM 12 VDC motor controller that you can, hopefully, adapt to the foot control potentiometer.  Something like this:

https://www.amazon.com/PWM-Mot...3TGSJASHDYPMG9Q0T530

Add one of these 12V 20A power supply bricks, and you've got a complete reversible 12V motor drive system.

https://www.amazon.com/ALITOVE...TG9nQ2xpY2s9dHJ1ZQ==

Ordered the controller and transformer. Still not sure which/what pedal to get. Also started tightening up the gearbox. I saw one of the inner cogs was not ideally aligned so I took off that gear and messed with the spacers and put it back and then took it apart and did it again like two more times and then I got it lined up as best I thought it could be and snapped the snap ring back on it and noticed that the big gear had some flat teeth.

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So I could see it was three big cogs riveted together so I popped off the spring clip—

and that damn thing sailed off into a far corner of the shop, never to be seen again. I have a box of spare spring clips somewhere so I searched for those first...nada.

Anyway, moving right along I drilled out the rivets and clocked the two outside gears 90 degrees to line up the next rivet hole and I was about to pop another two rivets in that when I noticed that the center hex hole was no longer a hex hole. So I clocked it another 90. Got some steel rivets and used the vice to pull them with my little hand rivet set. Now there are gear teeth all the way around.

I tied it back on with a paper clip for now and it tested OK. So I just need to source another C clip for it.

Started looking at the handle side of the bead roller. It's a shaft with a flat. The big final gear on the winch has some holes in it and I was thinking I could make a coupler using those. I may have to call upon my machinist friend.

While I'm waiting for my electric stuff I went ahead and painted the bead roller frame with some left over hammertone.

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Then I got impatient andIMG_6912

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Bead roller progress. I got my cheap AC/DC converter and the motor control. Haven't set up the power box yet but the controller works as it should.

I had my friend Mike turn a collar for me with a set screw so I can make a coupler.

I laid the setup down on the table to figure out how to bracket them together.

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I think I'll cut a couple pieces of 1x square tubing and through-bolt them even with the bottom edge of the roller body, then weld plate to the bottom of them and extend it and drill for the gearbox.

The new AC to DC box will fit pretty neat.

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And the controller should be easy to mount as well. (I still haven't decided what pedal to get).

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I spent a couple hours today cutting and tacking together the other half of the coupler.

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"I still haven't decided what pedal to get".

Ideally, the pedal's potentiometer resistance should be the same as that little control you're turning to vary the speed up and down.  Measure that control's resistance with an ohmmeter (disconnect the wires before you measure resistance) and get a pedal with a resistance range to match and you'll be in like Flynn.

That controller is pretty slick!   It's amazing what's ut there just waiting for us to spend our moolah on!

Last edited by Gordon Nichols

Will do, Gordon. Thanks!

Spent an hour and a half dry-fitting parts for the mounting bracket after dinner. Two 11-inch bits of 1-inch square and a 17 by 2 5/8 inch bit of 3/16 plate, with a 7-inch foot on it to put the platform under the center (by weight) of the gearbox.

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Drilling pilot holes through the square tubes first, then I'll clamp them to the roller's frame and drill and tap that, bolts all the way through that'll act as studs on the opposite side.

I'll probably fold the close corner of that plate up, as well as the far edge, to impart some lateral stiffness before welding it to the square tubes. Also leaning toward making a mounting plate for the whole tool instead of clamping it in a vice.

We do have fun here....

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Not all potentiometers of the same value are the same.

Some are 'linear' (half way up is half the total resistance, etc.) and on some, the resistance increases geometrically (or logarithmically) as you crank them up.

The latter are (or used to be) called 'audio tapers' because they used to be used to control audio volume levels (before the digital age).

So, if you're going to measure the resistance of that pot you're testing with, note how the resistance changes as you twist the knob. Does it change the same for a given amount of twist at the low end as at the high end, or change a little at first and then a lot?

Whatever it does, look for the same kind of winding in the pedal you get. If your motor needs one and you get the other, it will be almost unusable.

Uh, feeling like Cliff Clavin again.

.

@DannyP posted:

You're OK Mitch, as long as you don't tell us that drinking alcohol makes you smarter by killing the slow and weak brain cells first LOL!

Mitch is exactly right, a guitar volume pedal is probably audio taper(which is a logarithmic change in resistance). But if it's an effect pedal, then most probably linear.

C'mon, that was one of Cliff's best theories!  As long as you don't get too drunk and kill too many at once...

I just looked at the foot pedal from one of my wife's Brother quilting machines.   There is a huge risk involved with this endeavor - There is nothing more terrifying than an Irishwoman who has had her sewing machine messed with - But peeking inside (Don't you guys say NUTHIN'!) it has a linear potentiometer with a slide that goes back and forth moved by a roller driven by a ramp on the backside of the pedal.  The pot looks like one of these:

https://www.digikey.com/en/pro..._G3UwnBoCL64QAvD_BwE

It must be a relatively tried-and-true design.  It is the same model on all of her Brother machines and it says "Model T" on the bottom (no kidding).  Any Brother (or other) sewing machine store will have replacements in stock or certainly on Amazon.

Now for the important stuff:

It has a 1/8" Earbud-style, 2-wire audio connector on the end of a 4' cord to plug into the side of the machine.

Pedal up (at rest) shows exactly 50K ohms on my trusty digital Fluke Ohmmeter.

Pedal down (full speed) shows exactly 1K ohms.

The action is linear.  Half pedal shows about 25K ohms.

Then I got really brave and tested one of the other pedals (she has three, all Model Ts and she was on the phone at the time - Shhhhhh......)

That one showed 52.4K ohms pedal up.

Pedal down showed 1.026K ohms

So it looks like the range is NOT super-accurate for the application, and the important range limits look like 1K - 50K ohms

Hope this helps, Ed.  Go measure your pot.  You may just luck out.  If not, a different linear (straight-line) pot is readily available on Amazon.

@DannyP posted:

It's legal here in NY, IF you have a medical marijuana card. That's a big IF.

Can't you buy Ganja in NY if you have a membership card showing you're a Rastafarian and, therefore, you need if for "religious purposes" ...or has Cuomo shut down those services, too?

An interesting fact is there are a dozen legal marijuana dispensaries within 20 miles of Hershey, PA. I've been told (ahem!) the local sales of Hershey's chocolate are in direct proportion to those dispensaries sales of weed. Don't know that for sure, but it does  make sense....I've been told (ahem!).

Not shopping today so

Initial startup with the cover on it indicated some interference. The rivets I put on the first gear were too long. So I ground the tails down and tried again.

At this point it's down to the finer things. I still want to get a pedal to control the speed, as it's a bit awkward taking your hands off the work to dial in the movement. Once I find that and get it jacked in I'll probably clean up the cover, make a little box over the power cord lugs and such, maybe paint it black.

OK so I've been using the bead roller and it works much better with the reinforcement and motor drive. But I started this whole thing trying to get a foot pedal control, and I'm not quitting until I have that.

With Gordon's help we determined that my pot is a 100k ohm model, not 50k like the sewing machine pedals. With no good way to know for sure what the commercially available cheap pedals were, I decided to make one. My first idea was to get a little gear and rack from McMaster Carr and rig that to turn my existing pot, relocated into a foot pedal housing of my own design.

But Gordon pointed out that 100k slide pots are easy to get, so I bought one of those thinking the housing and linkage would be easier.

It came the other day.

Tested good:

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I drew a + on the zero side ("this end down") and rooted about for a little metal box to put it in that will work with the EMPI gas pedal I bought for the Spyder and then didn't use.

Scrap bucket yielded treasure, as always.

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Slotted it with the grinder.

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Folded a little piece of .050 aluminum over the plastic slider to make it more rugged.

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Snipped another piece into the rough shape of a c-shaped pushrod.

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And that's all for now. I need to make a solid mount inside the box for the pot. There are little threaded screw holes in each end but I've no idea what screws fit it (tried eyeglass screws; too small). I'll probably use epoxy and some plastic bits to make a surround for it and snap it in place.

Ridiculous all around, I know.

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With no good idea what screws this little pot wants, I decided to make a bracket to hold it in place and use available (larger) fasteners to attach it to the pedal box.

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I grabbed a bit of sheet steel and wrapped it around an old number stamp that's close to the size of the switch. The fold is to space the switch out from the edge of the box and center it in the slot.

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I'll solder pigtails to the pot and then dab a little silicone or Liquid Nails on it to hold it in the bracket.

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Yeah, tiny is part of the problem.

The smaller the mass of the thing you're soldering, the quicker it heats up and the hotter it gets. So, almost as soon as the solder flows, the delicate bits attached to the lug get all incandescent on you, which is generally a bad thing.

A clip of fat metal of some kind between the lug and the delicate innards will (in theory) absorb the heat before it gets to the innards. And yeah, finding somewhere to attach the clip can be a creative challenge.

This is why they make those anemic little 7-watt soldering irons for electronics applications - they give you more time between solder starting to flow and total meltdown.

Maybe you've found the reason why normal people don't try to build a foot switch for the bead roller they build when they're fabricating a hard tonneau cover for their replica 550 Spyders.

.

.

Here's a photo of a store-bought soldering heat sink clip being used to prevent the frying of a delicate electronic thing as the leads are soldered to connecting wires.

The heat sink goes between where the heat is coming from and the thing you're trying to protect.

This clip is marginally better than a plain ole alligator clip because it has (in theory) a little more contact area in its jaw than the alligator clip, but I think they sell them mostly to engineers who want to believe all that theory they paid a lot to study in engineering school.



SolderHeatSink

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I've soldered stuff since forever. Hemostats work really well for heat sinks. Bonus: they're stainless steel so rosin core lead solder doesn't stick.

Soldering tips: ONLY use rosin core electronic solder. Don't try to use plumbing solder and/or acid flux. NO NO NO on that.

I usually pre-tin wires, especially stranded. It cuts down the heating time before solder flows by a bunch. Less time heating is less heat-soak, and less chance of burning up semi-conductors.

Hemostats are your friend. And you can use them for other things, if you're so inclined.

Wait....

We're just ordinary folks!   (Most of us, anyway.)

Opus and friends

Lane is right, though...........    

Danny, too - Hemostats are your friends.  They even sell 'em in that big, red, tool vendor truck at Carlisle.  "Bill the Cat" uses them to hold his tongue out.

BTW, Leon had a typo in his post - The proper solder for ANY electronics is rosin core, not resin core (Damn you Spellcheck!).  The slight bit of rosin makes the solder lead stick to ferrous metals.  

The solder used for plumbing is Acid Core, which will attack the ferrous metals and quickly give you a poor electrical connection.

Bill the Cat knows this.  You should, too.

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Last edited by Gordon Nichols

All of the engineers I know (real or self-taught) seem to have three particular talents:  They keep an extensive junk box of spare parts (not to mention that they never throw anything away.....ever), the vision that things can go together for a purpose originally unintended and the ever-expanding skills to make that happen.  

Ed is the epitome of all of those.   Well done, sir!

back-to-the-future

Oh......   And there's a lot of perseverance in there, too!

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Last edited by Gordon Nichols
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