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]

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]

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]

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]

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.

[dll6]

Waferhead,
Do you remember what pressure sensor you used from sparkfun? Looking on there website at all the sensors they have in the price range you mentioned nothing seems to be sensitive enough from their description of the sensors.
You mention a round pressure type sensor $7 from sparkfun in onesies ... onesies ... is that a category under there "products" section?
Thanks Dave

[waferhead]

Waferhead,
Do you remember what pressure sensor you used from sparkfun? Looking on there website at all the sensors they have in the price range you mentioned nothing seems to be sensitive enough from their description of the sensors.
You mention a round pressure type sensor $7 from sparkfun in onesies ... onesies ... is that a category under there "products" section?
Thanks Dave

Onesies = unit=each

I used this one, works fine.

https://www.sparkfun.com/products/9375

If used with a system with HF, a couple big ferrite beads and and MOVs in the circuit would be a good idea, my old synchro
doesn't seem to care but the newer DX units seem to have far more delicate innards.

As per previous post, I did put a slight radii on the foot that presses on it, esp at the edges.
(basically sanded it with the paper on a soft surface)

I can max out current without completely squashing a grape

[dll6]

Waferhead,
Yeah I have the 250 DX and weld a lot of aluminium .. Id be interested to see your setup .. Im having trouble envisioning how I can mount it and still be useable in all the different positions and hands that I hold the torch.
(Idea) Maybe Ill try mounting it on some sort of holder for the feed wire .. Do they have something that advances the wire in the holder without having to stop and reposition the wire in the holder or will I have to design something?
(Idea) Better one .. in the finger of a glove, both gloves or several fingers with a selector switch oh, and something to recognize when your holding the torch ( I can just envision the torch in my lap and touching off that HF) .. 25 lbs might be a lot to apply without a lever and fulcrum .. Having used that sensor, what do you think?

[waferhead]

The 25 lbs spec is very misleading, I literally tried it with a grape under my thumb and got full scale without fully squashing the grape.
it's probably 25 psi, its ~1/3 sq inch, so ~8 lbs full scale.

With the bit of leverage from the trigger, 3-4 lbs full scale.

It is very comfortable to use for extended periods IMHO, and you could make the lever longer to suit you.

i velcroed it to the torch handle, which rotates 360 degrees, you can move it up/down the handle, or even remove it and work it with the other hand if needed...

[dll6]

Well next week my order from spark fun will be here and I'll double check my spare bottle of argon .. I'll keep you posted on the results

[waferhead]

I just made a little board to clip in the back of the $3 chinese contactor switch, everything attaches to it.
The pics from the biggining of the thread were eaten by bitworm, uploading them this time:

[dll6]

What would i need for a choke and mov? I know just enough about electronic components to get into trouble ..

[waferhead]

What would i need for a choke and mov? I know just enough about electronic components to get into trouble ..

I have neither, but I would probably install a 22v zener or two and wrap a few turns around a radio shack clip-together ferrite~at the machine end plug if I had a later model machine with HF.

Quite a bit of HF gets inducted into the cable even with excellent shielding.(I tried canare star quad, still happens)

FWIW heres a pic of one I'm using taped on my 181i torch...
The handle spins pretty freely

On a lift tig setup there is no HF issue to worry about.

[waferhead]

I finally had one break...
Snapped the arm off the $3 chinese switch, need to get another and swap the guts.
(Hooked it on something winding it back up after use)

I eventually replaced the tape with a velcro cable strap for a computer cables.