DIY wireless TIG foot pedal?

[DETown]

Jevon

Thanks a lot for the info on the 250.
I measured about 24v on the contacter,so I was kind of confused about the 10v you were refering to. I tried to trace out the circuit that the pot controlled using the schematic that is in the 250 owners manual. What a nightmare.That schematic is the fuzzyest and most convulated schematic I have ever seen. I could not make heads or tails out of it.
I was thinking of just using a wallwart on the 110 receptical on the front pane to power the receiver.Would make the electronics a little simpler.
One question I have, are they using the 10k pot as a voltage divider or what is its function in the circuit?
Am waiting to see what redbeerd finds out about his problem with the digital pots.
I looked at using a servo to rotate the pot that would really simpifly the eletronics part of the equation. I played around with some servo's and managed to get them working wirelessly using the Motieno's. The only problem with this is the servo's take a certain amount of time to rotate the about 300 deg to turn the pot the full travel. I think that they would not mirror the movemrnt of the pedal very well.
Lately I have been playing with some stepper motors which you can rotate pretty fast. The only problem is they need a driver board and the programming is a little harder.
Nice job on your circuit board. Something I have wanted to try for a long time.
I saw a post on the Arduino forum about using digital pots with a higher voltage. If I can find it I will post a link.
Will keep following you guy's progress and maybe I can get this thing sorted out.

[chrisweld]

Just seen this thread on radio controlled tig pedals...Ive just finished making one using a 2.4ghz transmitter and servo from a model shop (£40)..it didnt involve any circuits instead i went down the mechanical route and fitted potentiometer and microswitch off the servo.
I thought it would be slow to respond but in use its been amazing..having no cables attached to pedal is a real luxury and ive not experienced any problem with interference from welding HF.
Its been used on an Hitachi 500 amp tig

[redbeerd]

Just seen this thread on radio controlled tig pedals...Ive just finished making one using a 2.4ghz transmitter and servo from a model shop (£40)..it didnt involve any circuits instead i went down the mechanical route and fitted potentiometer and microswitch off the servo.
I thought it would be slow to respond but in use its been amazing..having no cables attached to pedal is a real luxury and ive not experienced any problem with interference from welding HF.
Its been used on an Hitachi 500 amp tig

Awesome!

Some pictures sure would be nice too.

How is your Rx unit powered? Battery?

Freakin cool that there are so many ways to make this work.

[DETown]

Just seen this thread on radio controlled tig pedals...Ive just finished making one using a 2.4ghz transmitter and servo from a model shop (£40)..it didnt involve any circuits instead i went down the mechanical route and fitted potentiometer and microswitch off the servo.
I thought it would be slow to respond but in use its been amazing..having no cables attached to pedal is a real luxury and ive not experienced any problem with interference from welding HF.
Its been used on an Hitachi 500 amp tig

How about a little more information. Would like to know what kind of servo you used to get the proper rotation, what type of rdio modules and possibly a sketch.
I investigatred this plan, but felt that the servo response was going to be too slow. I have all the stuff to do this except for the servo.
Any information would really kickstart my project.

[chrisweld]

How about a little more information. Would like to know what kind of servo you used to get the proper rotation, what type of rdio modules and possibly a sketch.
I investigatred this plan, but felt that the servo response was going to be too slow. I have all the stuff to do this except for the servo.
Any information would really kickstart my project.

I will post a photo but will be in a few days as away on hols...The servo was a bog standard one from the model shop,I bolted on a 50 tooth plastic gear to it which then drove 15 tooth gear on an expensive (£15 pot)
The response is slightly slower than` real time` of a wired pedal but the difference in practice is very little,and the benefits far outweigh the slight negatives....its actually quite good as it does crater fill.

[DETown]

I will post a photo but will be in a few days as away on hols...The servo was a bog standard one from the model shop,I bolted on a 50 tooth plastic gear to it which then drove 15 tooth gear on an expensive (£15 pot)
The response is slightly slower than` real time` of a wired pedal but the difference in practice is very little,and the benefits far outweigh the slight negatives....its actually quite good as it does crater fill.

I have a few questions about the gears you used and the rotation of the pot, plus a few others.
Don't want to bother you while you are on vacation, so will wait until you post the pictures

[ManoKai]

Attention All Planets of the Solar Federation: Have We Assumed Control? Checking to see if you elctromechanical whiz kids have made any forward progress. Shaka!

[DETown]

Has been kind of dead lately.
After reading that chrisweld had sucess with a servo driving a pot and because I had all the parts, this was the plan I am going to try. Haven't made a lot of progress but did manage to get the gear drive for the servo fabricated. Have to rebuild the engine in one of my cars,so will probably be a while until I can get back to this.

[redbeerd]

Attention All Planets of the Solar Federation: Have We Assumed Control? Checking to see if you elctromechanical whiz kids have made any forward progress. Shaka!

ManoKai, thanks for the continued interest and support. I have not made much progress in the past few weeks. Things got busy, as per usual. I do have some new ideas to try which should help me make forward progress on my newer digital pots. I also purchased an SSC Controls foot pedal for my machine (2014 AHP AlphaTIG200X) a few weeks ago. That thing is pretty nice! Just finished a thread on it here: http://weldingweb.com/vbb/showthread.php...51#post6164751

I'm still curious to hear how Jevon's pedal has been working out for him. I guess no news is good news? I've also thought about incorporating an op-amp circuit into my design. I haven't built those before so that may take some time to get around to. Seems simple enough, power and signal in, desired signal out. Badda bing! I wish.

That's all I got for now....

[Robert Hall]

That's the thing about creativity, it can't be done well on demand. It takes a while to percolate.

[chrisweld]

I`m back from holiday!...attached is picture of gear that plugs into welder,the foot pedal end is so simple I haven`t bothered to show it..the picture shows a very small micro switch that does the on/off....ive bought a 6volt supply now so I dont need to use battery.

[DETown]

chrisweld

What kind of radio are you using. Looks like a hobby R/C receiver. Also what activates the micro switch. Are you just using the initiall rotation of the servo to trigger the switch.
I have a cheap FlySky 3channel car sytem,but the problem I am having is that it does not rotate the servo the full 180 deg. There is no way to adjust the end stops on the transmitter so I am at kind of at a loss.
I have got this working on the Moteinos, but it would be a lot easier with the R/C setup because it has everything you need, charging circuit, lipo battery and everything allready wired up.
If I could figure out a way to increase the sweep on the servo I would go with the R/C setup. I also have a Pololu relay module that will operate the relay using one of the receiver channels to use for the pedal on switch.

[chrisweld]

Yes it is a hobby r/c kit (2.4ghz)..the servo like yours does just over 90 degree rotation but when geared up the potentiometer can be turned almost fully...and yes im just using the initial rotation of the servo gear to trigger the switch (I cut a few teeth out for micro switch roller to click into)
Looking at your pics i reckon you just need a different ratio of gears to solve the problem...also use a really good potentiometer with a smooth action-mine was by vishay

[DETown]

If I use the Moteino setup it will mirror the servo rotation with the rotation of the trasmitter pot. In other words a 300 deg. rotation of the transmitter pot will rotate the servo 180 deg. So on the other end I had to make the servo rotate the welder control pot the full span. I figured this would give better resolution by using the full 180 deg. span of the servo. It worked out to a 1.6 to 1 gear ratio.
It look like you are starting from the center point of the servo and only using half of the span, but it appears that gives you satisfactory resolution.
Like your idea of using the gear tooth to trip the switch. As I mentioned before I have a Pololu relay module that is triggered by a standard R/C signal, but I might just use your idea.
Got the cylinder head for my engine rebuild done today, so at least some progress on that. As soon as I get the rebuild done , I should be able to get back to this project.

[chrisweld]

the only problem that might come from using the whole sweep (300 degrees) of the servo is that they move quite slowly...gearing up means response is quicker?..

[DETown]

the only problem that might come from using the whole sweep (300 degrees) of the servo is that they move quite slowly...gearing up means response is quicker?..

I am moving the pot 300 deg which is its full range. The servo only rotates 180, so if you look at the picture the servo has the larger gear .
You are using a 15-55 combination which is a ratio of 3.66to 1. 3.66 x 90 is giving you 330 deg of pot rotation. pretty much the same as I am doing, except I am using the full rotation of the servo.
I can see what you mean about the speed ,because my setup will take twice as long to rotate the pot the full sweep.
Will have to see how it acts and make adjustments to make it right. The main problem I have with the R/C setup that I have will not move the servo a full 90 deg in either direction from the center position. It might be because the radio is for an R/C car not an airplane. If I could figure out how to make it do the full rotation I would use the R/C radio.
With the Moteino setup it starts from either end point not the center point and for the full rotation of the control pot it moves the servo 180 deg. I might have to figure out in the code how to start from the center point an then rotate 90 deg and adjust my gearing.
I guess the easyest solution would be to get another R/C radio, but I have got all these parts and would like to use them.
In case I decide to get another radio, what did you use.
Hopefully I can get my engine rebuild done and get back to this project.

[RADustin]

Hey guys,

Signed up just for this thread. I too plan on cutting the cord here shortly. Will be going the Xbee/Arduino Pro route as everything is 3.3V and I can get the 8MHz Arduino for power savings. Unsure if I will go digi-pot or PWM through an op-amp circuit. I like the digi-pot as it is much more universal but I understand resolution can suck.

Couple questions as I collect parts-

-can anyone confirm the connectors on a miller dynasty 200? Before I modify anything I will just be plugging into my pedal and machine. Eventually I plan to make the cord removable on the pedal for wired or wireless use. I do alot of welding in a car and I'm not sure the wireless performance of doing this- so I want the option.

-can anyone confirm if the miller has a dedicated wire on the machine side used to power the wireless adapters? A local field rep from Miller told me this is there?

-I will verify but I think the POT in the pedal is 10k? I order an SSC pedal I will use. Also, the contactor switch is NC or NO? I will verify but just looking to get the ball rolling while things are in the mail.

-can anyone confirm if there is a signal wire for remote amperage setting? I've had thoughts of making several Rx devices, one being torch mounts 2t/4t button with amp control on the torch. This would be handy in roll cage welding and other cramped awkward situations.




Quite a bit of lessons learned in this thread already so I am hoping things will go smooth. I appreciate everyone who is working on this posting up their feedback. It'd be great to get this to a level others can easily repeat. $500+ for a wireless miller pedal is a little crazy for the average DIY guy who has infinite ROI.

[RADustin]

anyone thought to use a DAC? I found this chip, 15V supply and 0-10V output. Sounds perfect.

Feed it from the 15V line on my Miller.

http://www.mouser.com/ds/2/256/MAX5312-104613.pdf

[DETown]

Quick update.
I finally got the R/C setup to rotate the servo 90 deg, The problem was the pot that the used had a big dead spot at each end of the travel. Replaced it with a standard pot and got 90 deg rotation.
In light of this I am going to use a setup like chrisweld used.
Just waiting for some gears that I ordered from ServoCity and then I can start fabricating the mount for my servo and the micro switch.
I scored a 14 pin plug on E-Bay for $20.00 and free shipping.
As soon as I make some progress I will post an update and some pictures.

[chrisweld]

Good luck detown..one thing to b wary of is the circuit board in the transmitter can easily get fried unless your very careful with it during manufacture-i accidently shorted abit of it out when it touched some metal while on...and has to buy another

[bkcorwin]

Hi Everyone, cool project. I am thinking I will build a wireless pedal as well. I replaced my original AHP pedal with an SSC so I think I will probably just go the route of driving the original pedal internals with a servo. Curious to see how everyones doing on there projects.

[DETown]

Made a little progress. Got my new servo drive done for 90 deg pot rotation. Also added a micro switch with a pin on the big gear to trigger it.
Going to try some tests in the next couple of day. Have to rebuid a four wheeler top end and a V four industrial engine, so will try to work this in between.
If chrisweld is still is still active I have a question about your setup. How did you do your antenna for the R/C transmitter in your pedel? Sorry about the fuzzy photo, seems like the auto focus on my camera is not working right. About time for a new camera anyway.

[chrisweld]

I made the foot pedal out of aluminium ,the batteries and antenna `hung` underneath...I didnt think location of antenna would make much difference even if inside it?

[DETown]

I made the foot pedal out of aluminium ,the batteries and antenna `hung` underneath...I didnt think location of antenna would make much difference even if inside it?

I am going to is my SSC pedel which is all steel, so I will probably have to figure out an external antenna.
Keep getting paying projects, so haven't had any time to work on this.

[ManoKai]

@ redbeerd - any updates with your wireless unit? Been play'n with an Arduino in prep for a Rotary Positioner build. Interested in seeing if you made any advances with the TIG pedal.