TIG remote DIY/ config ideas

[waferhead]

After consideration about patenting this little idea, I have decided I don't have the time, finances or inclination to jump through all the hoops, esp as the rules these days are "first to file" rather than first to invent.

Rather than get pissed at someone filing before I do, and in the interests of good karma, I hereby release this basic idea of the force sensitive pressure sensor controlled current control for a TIG torch as PUBLIC DOMAIN. Knock yourselves out.

If you dig it paypal me a few bucks, and if you make them commercially, perhaps giving credit/a few bucks and a sample would be good for your karma.

If "you" happen to be "Miller" a Dynasty 350 tigrunner and trolley would be a nice thank you ;-)

I'll be posting up some patterns/designs as I get to it, latest version will be a couple SMD caps, couple SMD resistors and sealed up in a flat rubber sandwich sealed at the edges for dust/water/damage resistance.

Greg McGee

I may make a few up to sell if I can come up with a robust, easily manufacturable design.

[waferhead]

FWIW my Synchro runs ~100mA on the remote contactor circuit, limits the contactor switch choices.

At least I really have a service manual on order now. (I think)

[waferhead]

Just an update---

After getting aa few hours on these, I despise using a footpedal.

If it was repetitive bench work, it might be OK, but for the situations I'm usually in these rock.

For fin detail work, it's absolutely unbeatable.

[Vinnie]

Originally Posted by waferhead

Just an update---

After getting aa few hours on these, I despise using a footpedal.

If it was repetitive bench work, it might be OK, but for the situations I'm usually in these rock.

For fin detail work, it's absolutely unbeatable.

Picture time lets see.

V

[waferhead]

Originally Posted by Vinnie

Picture time lets see.

V

You want to see it taped onto my TIG torch or to watch my mad amateur welding skillz?
I could probably still have pretty decent control range with a grape on the lever if you are curious how sensitive it is, although it could be made more or less sensitive pretty easily.

I can go from 3-310A on the synchro, but only very briefly as it's still on a 50A circuit.
The control knob on the Sycro (or the 181i) works the same, the knob sets max so you have min to whatever max is set to as the range... This can hit both ends easily with good control and light pressure.

Pics of the guts and assembled earlier in the thread, it's literally a pair of filter caps and a resistor, and the pressure sensitive bit as the second resistor in a simple circuit. The 2 caps connect the 3 wires used together to short out any RF across the resistor network just like a potentiomer.

If you need a contactor, you need 5 wires + shield, 3 for the "potentiometer" and 2 for the contactor switch, if lift start only, the current control alone MAY work for you, depends on the welder.

Canare star quad cable works great for the latter, as the shielding/design is excellent and it's made to be roadie proof, but only 4 wires.

[hackware]

great stuff waferhead...

found this thread looking to build a foot pedal for my cheap simarc ct520d box...

(could not see paying over $150 for a "pot in a box" foot pedal for a $300 welder)...

like you, my past life was more on the electronic side of things, and i am a welding noob...

(no accusations, you seem less welder noob than me... :-)

one idea i had, was a remote pedal/torch switch extension so you could use the switch on the torch, and the pedal for power control... (perhaps now defunct with your method...)

william...

[coronan]

Whats the latest? More Videos / pics?

[waferhead]

No updates, they work fine.

OK, I guess I'll have to shoot a video putting the control through its paces.

My real job kinda gets in the way of quality welding time, so don't hold your breath.

[Userkc14419]

I would love to see a video as I have thought about this same type project.

Have you ever thought about using the pressure type sensors. Not the ones which bend but the ones that have a pad that you press.

Or possibly just a typical slide type pot

thanks

[waferhead]

It uses a round pressure type sensor,~$7 from SparkFun in onesies.
It has sufficient current capacity and the proper range to work directly.

[zipzit]

You got me looking at the sparkfun website. How about a blackberry trackball for amperage control? You know the little white ball mounted in the center of a Blackberry cell phone? Not sure how that would feel with gloves, but it could be an interesting conversation. This would definitely require a controller (arduino?) so its not cheap, might be a fun project. You'd mount the small ball directly on the TIG handle. I think you'd have to assume 4 touch (4T operation).. push the trackball once to start the arc/gas flow, then spin ball up / down or right/left to engage amperage. User could custom program up down or left right directions (Remember when Will Smith got into the alien space ship in the movie "Independence Day" and had to turn his post-it note upside down to indicate how the ship's controls worked.. yeah, like that...) Push ball again, say 3x in rapid succession.. this would preclude erroneous inputs to the trackball and that would start the downslope disconnect process.

Track ball kit is cheap, but arduino controller and software development will require a little time and some money.

[waferhead]

The arduino solution (with whatever controller) could probably even be used as an advanced programmable pulser + upslope/downslope (within some yet to be deterimined limits)
I can see a one-3 line LCD readout taped to the torch already...

Sparkfun is a terrible website for hardware geeks, I try not to go there or I never get anything done.

The only "downside" of the pressure based variable resistor setup is it ~Just Works.
In a perfect world, you would also have a mechanical pot to use as a remote current limit so you basically could set everything up remotely.

I spent more $ and time getting/making up and stuffing the cable in the velcro'd cable wrap than I did making the actual control part.

[waferhead]

The arduino solution (with whatever controller) could probably even be used as an advanced programmable pulser + upslope/downslope (within some yet to be deterimined limits)
I can see a one-3 line LCD readout taped to the torch already...

Sparkfun is a terrible website for hardware geeks, I try not to go there or I never get anything done.

The only "downside" of the pressure based variable resistor setup is it ~Just Works.
In a perfect world, you would also have a mechanical pot to use as a remote current limit so you basically could set everything up remotely.

I spent more $ and time getting/making up and stuffing the cable in the velcro'd cable wrap than I did making the actual control head.

[zipzit]

Originally Posted by waferhead

Sparkfun is a terrible website for hardware geeks, I try not to go there or I never get anything done.

Waferhead, you can say that again. I've been wading thru Sparkfun and that directed me over to FlexiForce (the manufacturer of the sensor device...)

Were you able to use the power signal from your welder (the terminal that feeds the voltage to the rheostat voltage divider found in a normal foot pedal) or did you have to add a separate power supply? I'm thinking an inverter TIG welder provides somewhere between 5 v and 10v for that circult.. If so you could drive the system (including opamps) without an external battery or power supply..

also.. what force device did you use... a 25 pounder?

many thanks for sharing... zip.

[Userkc14419]

also curious where you got the little paddle type switch housing ?

[waferhead]

Originally Posted by Userkc14419

also curious where you got the little paddle type switch housing ?

The housing is a std $3 Chinese ebay TIG torch contactor switch, used because it existed, need a remote contatcor anyway..
(always start with a man on base if possible)

I made a little PCB routed from circuit board material to clip into the bottom of the switch housing that acts as the pad/cable attachment point mount etc.

The pressure sensor is rated at 20 lbs, but that rating is misleading, esp using a radiused edge pressure pad for uniform pressure distribution + the leverage from the paddle, has a very nice control range with light finger pressure.

The sensor and a 5K resistor are the only components other than the contactor switch and a couple filter caps, the resistive pressure sensor and resistor form a simple voltage divider. It uses the 10V reference as power.