Show & Tell: Thumb Controller For Needle Positioning

[Uwe]

I've been wanting to install a retrofit thumb control knob for needle positioning on one of my machines ever since I saw it on that new Adler 969.

My Tacsew T1563 made a good candidate to try a few things out, and it actually works!

The entire project of installing an Arduino controlled high-torque precision step motor drive is rather complex and I'll post more details later.

This video is just about how the thumb control knob works:

[TinkerTailor]

That is REALLY cool, I would have the jog wheel programmed a little different myself, but that is the beauty, you just change it in software. I would add a button or two. One to put the needle buried, and just rising, perfect for turning and one to place the needle up, right where it is easiest to remove the work.

I do like how you can set it to a position, and click for a whole stitch.

It is awesome to see more modern technology that is commonplace in other industries applied to sewing machines. Clutch motors are basically the same technology used in steam powered line shaft shops. Machinists even put vfds on drill presses now they are so cheap and steppers are everywhere with cnc, and cheap. Bout time someone started making this kind of stuff for sewing. I know how all that electronicalistic mombo-jumbo works, However i choose not to tinker with it myself. I'll leave that to you.

One question, Are you going to make a stepper stitch length adjuster to hit the corner exactly?

[dikman]

Brilliant! Can't wait to see the rest of it. (Speaking of steam-powered, the sound your machine makes when it's starting up is a bit like an old steam train wheezing as it first starts ).

[Uwe]

That sound may be me wheezing.

I actually had to turn down the sounds of the original video almost entirely because the step motor makes and infernal racket at slow speeds right now. It's dead quiet when stopped, and has an agreeable hum at high speed, but low speeds are a very disagreeable racket right now. The motor is just clamped to the table top for testing and every slow step it makes acts like a speaker coil with table top pretending to be a sound board.

The programming is indeed a big part of how the button (or any part of this motor drive system) behaves. Arduino programming is fun in a very geeky way. I just knew those engineering, math, and computer science degrees would come in handy some day! I plan to add a little touch screen to allow changing parameters and such.

I actually LOVE how well the speed pedal works. I'm using a modified Ernie Ball brand musician's sound effect pedal to control speed input:

Not exactly cheap at around $70, but it's by far best, most gradual and precise low speed control I've had so far. None of this weird optical gradient hacking, just hundreds of usable, gradual steps of speed input.

I initially bought the pedal to control a Variable Frequency Drive controller, but those 3-phase inverter class motors are wicked expensive,huge, and heavy. The pedal works perfectly as an Arduino input device and it's beautifully made, almost carved from solid aluminum.

[TinkerTailor]

I agree 3 phase motors are expensive, I use the drill press example cause many of the big ones have them already, hooked to a step pulley belt drive and/or gearbox to change speed. A twisty knob is way easier.

[Gregg From Keystone Sewing]

Excellent video, thanks for sharing.

[TomG]

Fantastic. Did you do the design/programming yourself or find instructions elsewhere?

Would it work on any of the servo motors like the Consew?

[Constabulary]

nice idea again but my right hand on the hand wheel can do the same I think...

[TinkerTailor]

nice idea again but my right hand on the hand wheel can do the same I think...

Yes the jog wheel is really just a mini handwheel. It is the "click to stitch" functionality that is the key and the foreshadow to the other functionality this setup has. It is an incredibly powerful computer for the amount of data and control involved with a sewing machine, and the programming support in the CNC machining world is immense.

Now that that functionality has been proven, the controller is open to many other variables like programmable speeds and stitch counts.

If you are in production, you could measure a seam, work out the number of stitches before the next turn, lets say 100, and then tell the machine to go slow for 10, ramp up and rip the next 80 and then slow down for the corner, stopping with the needle up 1-2 stitches from the corner to allow the user to place the stitch perfect. Stitching runs of belts this could be really nice.

There are so many ways this can go. It is basically 1/3 of a fully cnc sewing setup. The other thirds are stitch length/feed control and material steering.

The motor is pretty universal and machine independent, however controlling stitch length and feed is very machine specific.

And you still need someone to steer.

In reality, full CNC is going to be a pain in the donkey for the types of work most on this site do.

The needle position part Uwe has conquered is the most useful for the small project sewer.

The second part, stitch length automation comes up much less often as a need, and probably would seldom get used. The lever is right there.

For the third part, having the machine steer the work for you takes all the fun and fear away........Might as well order leather stuff from china...

[dikman]

I agree in that the needle positioning is potentially of great benefit, the rest....? While it would be very impressive in its implementation, I see little practical use for what most on this forum appear to use their machines for. And yes, in my opinion it would start taking the fun and enjoyment away. I can, of course, understand why Uwe would want to do it.........mainly because he can!

Uwe, my servos make assorted noises at very low speed, the worst is the one fitted to the Pfaff, this one has a small pulley on the motor and an 8" on the machine, and at very low speed it grumbles along and at a particular speed almost seems to create a resonance with the table!! The one on the Singer 211 is connected via a speed reducer setup and this is quieter at slow speed. I'd say that the reducer has the effect of allowing the motor to run a little faster but still give low overall machine speed so is happier because the revs are up a bit. Makes sense to me, at least.