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Old 07-24-2015, 06:36 PM
Ing6018 Ing6018 is offline
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Join Date: Jul 2015
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Default Breath Controller to Operate a Welder?

Please excuse the length of this message.

About me:
A couple years ago I picked up a used EWI4000 wind controller for personal use. While this is a device with built in sound generation, it has a Midi out for controlling other modules and devices. I have and electronics background and followed the breath controller posts but I have no "hands on" experience with Midi.

I am hoping that your creativity and knowledge of Midi can help someone in need.

I am a member of several welding forums. On one of the forums a member recently asked about using some sort of mouth-operated device to control a welder. The member is a triplegic (he has use of one arm and only very gross motor skills in the other). He unable to use his welder effectively with available technology.

Based on the responses, there does not seem to be a ready-made solution and other than some hypotheticals, no viable options are emerging. After thinking about it I believe a breath controller may be a very appropriate technology to use. I just don’t have the know-how.

Welder
The member is using a TIG (Tungsten Inert Gas) welding process. In Tig, the operator holds a “torch” between the fingers (somewhat like a very fat pencil or soldering iron). The torch is connected to the welder through a power cable, and a shielding gas hose. The other hand is used to hold a very thin filler wire.

When the torch is very close to the target metal (fractions of an inch), the operator normally steps on a pedal to initiate an electric arc from a tungsten electrode. This essentially melts the base metal. By varying the foot pedal up/down, the operator can vary the current (heat) put into the weld site. Also, while the pedal is pressed, Wire is had fed into the arc zone to melt and add filler to fuse with the metal being welded. An inert gas flows over the weld site to displace oxygen and prevent oxidation.

The process resembles electric soldering except that the operator is wearing a face shield, gloves and protective gear.

The member does not have the ability to manage a foot control. There is a small torch-mounted control available that allows fingertip control of arc-start and amp-control but the member does not have the motor skills to use that option.

I do not have particulars on his welder model, but I have an older Tig welder and the pedal has a small micro switch to initiate the arc and 10K potentiometer to control the amperage (the max amperage is pre-set at the welder and the pedal varies between min/max). I suspect his model has something similar.I believe those are the only parameters that need to be controlled.

The key issues here are providing the user with a comfortable, effective method of controlling the welding process and has the granularity to allow the user to customize arc initiation, arc stop, and amperage.

Solutions might include:
*Bite-Hold to initiate and continue weld – Bite release to stop the weld.
*Momentary Bite to trigger weld-on process and second momentary Bite to stop
*Breath to vary the amperage.
*I am not sure if some sort of pitch-bend or velocity would offer any benefits but they might provide user customizable preferences.
* A wireless option might be beneficial. However, the Tig process puts a lot of current (sometimes hundreds of amps) into the weld zone. Because of the proximity of the sensors to the weld zone (AC, DC, pulsed, varied frequency) I don’t know about interference if some sort of wireless solution is envisioned.

This project is above my skill-set but I started out thinking about a breath controller that controls a keyboard volume pedal. That addressed the amperage control but not the stop/start.
After days of searching I found the "MIDI to Potentiometer" board on this site:
http://getlofi.com/midi-to-potentiometer/
This "variable Pot" looks like the type of item I am trying to assemble but when I follow the link, it takes me to this site, but I am unable to find the item.

Any ideas you may have would be appreciated.

If any promising (and affordable) options pop up, I can try and prototype on my welder.

Thanks for your time.

Dan
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