On Fri, 16 Jan 2009 08:47:53 -0600, "Pete C."
wrote:


Don Foreman wrote:

On Tue, 13 Jan 2009 00:40:05 -0600, Don Foreman
wrote:

Had another thought today:

Perhaps the young doc hasn't yet encountered a patient who has
expertise in a related field and doesn't yet know how to deal with
that. It's not uncommon among highly-educated young chargers. I have
ample experience with smoke, feathers, fancy dancing and
bafflebull****. I didn't deal with medical folks during my working
life but I dealt with plenty of high-talent young PhD's in science and
engineering.

A conversation with a decades-experienced "device nurse" was
enlightening.

She said that the doc would not adjust parameters in an attempt to
optimize compatibility with welding, he would adjust them to optimize
performance for the medical purpose required and intended.

Well, duh! That's exactly what he should do. Welding is optional,
dead guys don't need to weld. I could fault the young Doc's
people skills but I gotta respect a no-compromise attitude re doing
what is medically best whether I like it or not. That places
responsibility for risk of welding squarely upon me, which is exactly
where it belongs.

The responsibility for the potential risk of welding belongs on you,
however the responsibility to adjust the device to settings to
accommodate the *requirements* of the *customer* belong on the service
provider i.e. the doctor.

The central issue is which requirements should govern if there is a
tradeoff. The doc wants to optimize for best chance of intended
medical function and performance with no compromise of that objective.
I agree with that priority. I don't have to weld to survive, but I do
have to survive to weld.

Don Foreman wrote:

On Fri, 16 Jan 2009 08:47:53 -0600, "Pete C."
wrote:


Don Foreman wrote:

On Tue, 13 Jan 2009 00:40:05 -0600, Don Foreman
wrote:

Had another thought today:

Perhaps the young doc hasn't yet encountered a patient who has
expertise in a related field and doesn't yet know how to deal with
that. It's not uncommon among highly-educated young chargers. I have
ample experience with smoke, feathers, fancy dancing and
bafflebull****. I didn't deal with medical folks during my working
life but I dealt with plenty of high-talent young PhD's in science and
engineering.

A conversation with a decades-experienced "device nurse" was
enlightening.

She said that the doc would not adjust parameters in an attempt to
optimize compatibility with welding, he would adjust them to optimize
performance for the medical purpose required and intended.

Well, duh! That's exactly what he should do. Welding is optional,
dead guys don't need to weld. I could fault the young Doc's
people skills but I gotta respect a no-compromise attitude re doing
what is medically best whether I like it or not. That places
responsibility for risk of welding squarely upon me, which is exactly
where it belongs.

The responsibility for the potential risk of welding belongs on you,
however the responsibility to adjust the device to settings to
accommodate the *requirements* of the *customer* belong on the service
provider i.e. the doctor.

The central issue is which requirements should govern if there is a
tradeoff. The doc wants to optimize for best chance of intended
medical function and performance with no compromise of that objective.
I agree with that priority. I don't have to weld to survive, but I do
have to survive to weld.

Yes, but "optimize" is the key, not "use most conservative default
setting and not bother researching the options".

On Fri, 16 Jan 2009 00:34:13 -0600, Don Foreman
wrote:

Had another thought today:

Perhaps the young doc hasn't yet encountered a patient who has
expertise in a related field and doesn't yet know how to deal with
that. It's not uncommon among highly-educated young chargers. I have
ample experience with smoke, feathers, fancy dancing and
bafflebull****. I didn't deal with medical folks during my working
life but I dealt with plenty of high-talent young PhD's in science and
engineering.

You are throwing a big EMF and RF wrinkle into the system that they
never thought of during initial testing and field trials, and doesn't
come up all that often in use - They simply expect all of the grateful
recipients of their medical largesse to meekly back down and give up
all activities that would add the slightest bit of extra hazard,
including an irrational severe allergy to microwave ovens.

They don't know you very well, do they? ;-P

Don't feel bad, that's the same faulty logic behind the "No 2-Way
Radios or Cellphones in the Hospital" decrees. Rather than study the
potential conflicts and determine limits that are technically
required, a blanket edict is a whole lot easier and faster.

A conversation with a decades-experienced "device nurse" was
enlightening.

She said that the doc would not adjust parameters in an attempt to
optimize compatibility with welding, he would adjust them to optimize
performance for the medical purpose required and intended.

Well, duh! That's exactly what he should do. Welding is optional,
dead guys don't need to weld. I could fault the young Doc's
people skills but I gotta respect a no-compromise attitude re doing
what is medically best whether I like it or not. That places
responsibility for risk of welding squarely upon me, which is exactly
where it belongs.

Dead guys can't weld anymore, yes. But guys who can't weld anymore
might as well... No, let's not go there any sooner than we have to.

They have to look at this as a Quality Of Life issue, and your task
is to beat that fact through their heads. With their own arm.

If nothing else, get some hard numbers on limits, and get them to
sign off on your sensor suite to measure them real-time. You are
developing a new study group, one researcher and one patient. No
rules that they can't be the same body.

You might end up with a vest that has sensors and a big buzzer -
when the sensors go over limit the buzzer goes off, it's time to
reposition the weldor, the work and/or the cables.

And there is always that mule-kick internal alarm if the external
one doesn't work - that should provide impetus to get it right the
first time.

-- Bruce --

On Fri, 16 Jan 2009 10:43:43 -0800, Bruce L. Bergman
wrote:

snip
Don't feel bad, that's the same faulty logic behind the "No 2-Way
Radios or Cellphones in the Hospital" decrees. Rather than study the
potential conflicts and determine limits that are technically
required, a blanket edict is a whole lot easier and faster.

I used to work RF/Radio. It never stopped their security
people from using radios anywhere that I could tell.

I remember one emergency room radio/install that gave us
fits. Sometimes when they keyed up the local base, (security
office was right beside the ER entrance. Common
configuration.) the main ER entry sliding power door would
open/cycle. That one was lots of fun!

All sorts of radios wandering around ER back then. Police,
security, ambulance, two-way techs...

I remember VP Cheney getting one of these or similar a while
back. It seems like that should have opened a can of worms
trying to keep people for making it go off falsely.

I'll bet he didn't volunteer to stand in front of the new
crowd control gizmo that they were pushing/demonstrating.

--
Leon Fisk
Grand Rapids MI/Zone 5b
Remove no.spam for email

Leon Fisk wrote:

I used to work RF/Radio. It never stopped their security
people from using radios anywhere that I could tell.

I remember one emergency room radio/install that gave us
fits. Sometimes when they keyed up the local base, (security
office was right beside the ER entrance. Common
configuration.) the main ER entry sliding power door would
open/cycle. That one was lots of fun!


Years ago when I was the lonely IT guy, a supervisor keyed his radio right next to my main
server and it abended. I think he saw his demise in my eyes, he sure left my office
quickly.

Wes

Don Foreman wrote:

Many industrial sensors integrate this function with a circuit that
switches at some level of field intensity, providing a binary or
"on-off" signal. I'm using a linear hall sensor that provides a
voltage proportional to field strength, about 4.25 millivolts per
gauss. It's the HAL400C from Micronas. Current product would be the
HAL401:

http://www.micronas.com/automotive_a...ion/index.html

Why that one? Because I had 4 of them in my junkbox. Allegro also
makes Hall sensors, and Honeywell used to, probably still does. I
like the differential output on the Micronas for rejection of noise. 4
millivolts isn't much signal when 60 Hz is in the passband. You
probably know what happens when the ground comes loose on a microphone
or magnetic phono jack: HUMMMM! I want this sensor to sense magnetic
field but ignore E field. I'll measure that separately.



Sheesh, you have a nice junkbox. I tried newark and digikey and they didn't carry it.

Thanks,

Wes

On Fri, 16 Jan 2009 11:33:19 -0600, "Pete C."
wrote:


Don Foreman wrote:

On Fri, 16 Jan 2009 08:47:53 -0600, "Pete C."
wrote:


Don Foreman wrote:

On Tue, 13 Jan 2009 00:40:05 -0600, Don Foreman
wrote:

Had another thought today:

Perhaps the young doc hasn't yet encountered a patient who has
expertise in a related field and doesn't yet know how to deal with
that. It's not uncommon among highly-educated young chargers. I have
ample experience with smoke, feathers, fancy dancing and
bafflebull****. I didn't deal with medical folks during my working
life but I dealt with plenty of high-talent young PhD's in science and
engineering.

A conversation with a decades-experienced "device nurse" was
enlightening.

She said that the doc would not adjust parameters in an attempt to
optimize compatibility with welding, he would adjust them to optimize
performance for the medical purpose required and intended.

Well, duh! That's exactly what he should do. Welding is optional,
dead guys don't need to weld. I could fault the young Doc's
people skills but I gotta respect a no-compromise attitude re doing
what is medically best whether I like it or not. That places
responsibility for risk of welding squarely upon me, which is exactly
where it belongs.

The responsibility for the potential risk of welding belongs on you,
however the responsibility to adjust the device to settings to
accommodate the *requirements* of the *customer* belong on the service
provider i.e. the doctor.

The central issue is which requirements should govern if there is a
tradeoff. The doc wants to optimize for best chance of intended
medical function and performance with no compromise of that objective.
I agree with that priority. I don't have to weld to survive, but I do
have to survive to weld.

Yes, but "optimize" is the key, not "use most conservative default
setting and not bother researching the options".

A very good point, Pete. Our half-hour conversation with the device
nurse persuaded me that these people really do "tune" these things to
the individual patient.

Mercy Heart Center (Coon Rapids) was rated one of the top 100
Cardiovascular hospitals in the nation every year 2003 thru 2007. I
don't think these people are hacks. I do think the young doc just
hadn't dealt with a question like mine (or crusty old engineer like
me) so he went into defensive "blow smoke" mode. There ain't a soul
alive with Dr. in front of his or her name that didn't become
proficient at that in grad school. It's a survival skill.

They probably don't research options beyond medical considerations.
That's now OK with me. Having done some of that research now, I can
see why. They don't have the training in physics or engineering, and
it's impossible to rigorously research an undefined situation with
several variables. I can research my particular situation, and I'm
doing that, but I doubt that they'd know what to do with the data any
more than I can read an XRay or interpret a lab report.

I learned that parameters "could be optimized for welding" from a
senior (as in top-level) engineering fellow but he didn't say what
compromises that might entail. I'd rather it be optimized for
intended medical function, then I'll compromise as necessary re hobby
welding. Initial field strength measurements made today with MIG (in
my particular situation) are quite encouraging.

On Fri, 16 Jan 2009 08:14:49 -0800, Larry Jaques
wrote:



Perhaps the young doc hasn't yet encountered a patient who has
expertise in a related field and doesn't yet know how to deal with
that. It's not uncommon among highly-educated young chargers.

Excellent insight, Don. Gonna show him your DonRube device?

I doubt if he'd care, but the guys at Boston Scientific have expressed
interest. I sent them an update report with photos tonight. If you'd
like to see it, lemme know.

A conversation with a decades-experienced "device nurse" was
enlightening.

She said that the doc would not adjust parameters in an attempt to
optimize compatibility with welding, he would adjust them to optimize
performance for the medical purpose required and intended.

But he should, as you'll be welding after the operation. He needs to
adjust the device to protect you as much as possible, and that means
to -your- lifestyle, not his optimum view.

His view is that he will adjust the device to protect me as much as
possible. Ya can't optimize everything. Optimization is almost always
a "best compromise". In order to do it, one must prioritize the set
of outcomes, taking into account their probabilities and cost or
benefit.

I can easily understand how a concientious Dr. would balk at
compromising medical optimality for a rather ill-defined need or
desire. I can't fault him for that. How much does he tweak this
parameter or that to achieve what gain in meeting the new goal? If I
were he I'd take the same course he's taking.

Lifestyle adjustments do sometimes result in more quality life, which
has some appeal for me. I don't want to live life past the point of
enjoying it, but life is still quite enjoyable. I hadda quit smoking,
I'm now walking 3 brisk miles every (goddamned) day, etc.

I'll be MIG and/or TIG welding after the procedure only if I'm
reasonably confident that I won't get whacked on me arse by doing it.
I'll still be gas welding and brazing in any case.

On Fri, 16 Jan 2009 18:29:57 -0500, Wes wrote:

Don Foreman wrote:

Many industrial sensors integrate this function with a circuit that
switches at some level of field intensity, providing a binary or
"on-off" signal. I'm using a linear hall sensor that provides a
voltage proportional to field strength, about 4.25 millivolts per
gauss. It's the HAL400C from Micronas. Current product would be the
HAL401:

http://www.micronas.com/automotive_a...ion/index.html

Why that one? Because I had 4 of them in my junkbox. Allegro also
makes Hall sensors, and Honeywell used to, probably still does. I
like the differential output on the Micronas for rejection of noise. 4
millivolts isn't much signal when 60 Hz is in the passband. You
probably know what happens when the ground comes loose on a microphone
or magnetic phono jack: HUMMMM! I want this sensor to sense magnetic
field but ignore E field. I'll measure that separately.



Sheesh, you have a nice junkbox. I tried newark and digikey and they didn't carry it.

I got it from DigiKey some time ago. It's not a current part, I've
had it awhile. Parts now available from Allegro, Melexis, Honeywell
and others may well be better.

On Fri, 16 Jan 2009 18:29:57 -0500, Wes wrote:

Don Foreman wrote:

Many industrial sensors integrate this function with a circuit that
switches at some level of field intensity, providing a binary or
"on-off" signal. I'm using a linear hall sensor that provides a
voltage proportional to field strength, about 4.25 millivolts per
gauss. It's the HAL400C from Micronas. Current product would be the
HAL401:

http://www.micronas.com/automotive_a...ion/index.html

Why that one? Because I had 4 of them in my junkbox. Allegro also
makes Hall sensors, and Honeywell used to, probably still does. I
like the differential output on the Micronas for rejection of noise. 4
millivolts isn't much signal when 60 Hz is in the passband. You
probably know what happens when the ground comes loose on a microphone
or magnetic phono jack: HUMMMM! I want this sensor to sense magnetic
field but ignore E field. I'll measure that separately.



Sheesh, you have a nice junkbox. I tried newark and digikey and they didn't carry it.

Thanks,

Wes

See
http://www.micronas.com/company/cont...%5Btype_4%5D=0
for distributors of Micronas parts.

Allegro has been generous with samples in the past, don't know how
they are these days.

If you could use a couple of single-ended (not differential output)
ratiometric linear hall sensors, ping me by email. They're Honeywell
devices from a decade ago. I have a spec sheet I can scan.

Keywords:
In article , Don Foreman wrote:
On Fri, 16 Jan 2009 18:29:57 -0500, Wes wrote:

Don Foreman wrote:

Many industrial sensors integrate this function with a circuit that
switches at some level of field intensity, providing a binary or
"on-off" signal. I'm using a linear hall sensor that provides a
voltage proportional to field strength, about 4.25 millivolts per
gauss. It's the HAL400C from Micronas. Current product would be the
HAL401:

http://www.micronas.com/automotive_a...unction/hal_40
1/product_information/index.html

Why that one? Because I had 4 of them in my junkbox. Allegro also
makes Hall sensors, and Honeywell used to, probably still does. I
like the differential output on the Micronas for rejection of noise. 4
millivolts isn't much signal when 60 Hz is in the passband. You
probably know what happens when the ground comes loose on a microphone
or magnetic phono jack: HUMMMM! I want this sensor to sense magnetic
field but ignore E field. I'll measure that separately.

Sheesh, you have a nice junkbox. I tried newark and digikey and they didn't
carry it.

Thanks,

Wes

See
http://www.micronas.com/company/cont...ex.html?search
%5Btype_2%5D=USA&search%5Btype_1%5D=0&search%5Bty pe_4%5D=0
for distributors of Micronas parts.

Allegro has been generous with samples in the past, don't know how
they are these days.

If you could use a couple of single-ended (not differential output)
ratiometric linear hall sensors, ping me by email. They're Honeywell
devices from a decade ago. I have a spec sheet I can scan.

Amalog Devices also makes Hall Effect sensors. They should be avaialble
from a number of distributors.

Doug White

Don Foreman wrote:

On Fri, 16 Jan 2009 18:29:57 -0500, Wes wrote:

Don Foreman wrote:

Many industrial sensors integrate this function with a circuit that
switches at some level of field intensity, providing a binary or
"on-off" signal. I'm using a linear hall sensor that provides a
voltage proportional to field strength, about 4.25 millivolts per
gauss. It's the HAL400C from Micronas. Current product would be the
HAL401:

http://www.micronas.com/automotive_a...ion/index.html

Why that one? Because I had 4 of them in my junkbox. Allegro also
makes Hall sensors, and Honeywell used to, probably still does. I
like the differential output on the Micronas for rejection of noise. 4
millivolts isn't much signal when 60 Hz is in the passband. You
probably know what happens when the ground comes loose on a microphone
or magnetic phono jack: HUMMMM! I want this sensor to sense magnetic
field but ignore E field. I'll measure that separately.



Sheesh, you have a nice junkbox. I tried newark and digikey and they
didn't carry it.

I got it from DigiKey some time ago. It's not a current part, I've
had it awhile. Parts now available from Allegro, Melexis, Honeywell
and others may well be better.

You can also often obtain them from the brushless motors of old floppy
drives, etc. They often use three hall effect sensors to determine the
angle of the magnetic rotor, in order to commutate the current to the
windings of the motor. You'd have to guess at the specifications, but if
in doubt about how to use it, you could measure the voltages with a scope
whilst it is still working in the floppy drive.

Chris

Don Foreman wrote:

If you could use a couple of single-ended (not differential output)
ratiometric linear hall sensors, ping me by email. They're Honeywell
devices from a decade ago. I have a spec sheet I can scan.


I found a single ended one in Newark. I'll play with that. I thank you for your kind
offer.

Btw, I liked Joseph Gwinns idea of you turning your sensor into a warning system should
you decide welding is managable.

Wes

On Jan 13, 12:40*am, Don Foreman
wrote:
Summary: * not lookin' promising.

I've had contact with some good people: *a *senior fellow engineer at
a major ICD mfr, a former employee (engineer) of a major ICD mfr *and
friend of many years, *my wife's niece who is a former cardiac nurse
of 30+ years experience, and helpful others.

Findings:

There are reported cases of weldors returning to work with ICD's but
the reports are sketchy on details. One report mentions a minimum
distance of 24" between weldor and cables, work and torch. *That ain't
how I weld: *my face is right in there with 2 diopter lenses in my
mask. *

The experience of having a defib misfire has been variously described
as being hit by lightning and being kicked in the chest by a mule. I'd
rather skip that experience. *Welding is fun, being kicked in the
chest by a mule very probably isn't. * * * *

I can't seem to get data on acceptable field strengths (E-field and H
or B field) that won't cause an ICD to malfunction. *I opined that
this is probably because the goddamned lawyers make this data highly
proprietary. *That was confirmed by the engineer (and friend) formerly
employed by a major mfr. *Goddamned lawyers. * *

So I'm about SOL here, not being up for a mule kick in chest while
experimenting, candyass that I am. *

Helluvit is that I have no friends who can do TIG and MIG, though Karl
Townsend's son "the kid" may be a savior. *Neither of my sons are at
all interested. *One daughter is, and she's done some nice work with
MIG *but she lives in Brooklyn NY so she's not exactly local.

Mar, bless her hawrt, has volunteered that she might do a Vo-Tech
course in TIG and MIG. *She'd be a natural, that based on her
precision quilting and prowess with handgun, both hand-eyes
coordination activites. *TBD how that goes, but whatta teammate for
even considering it, eh? *Hey, she severely aced ground school for
pilot licence for previous hub in the bad old days. Highest score
they'd ever seen if I recall correctly. *What a fool he was for doing
her wrong, what good luck for me and eventually us. Goin' on 30 years
now and it just keeps getting better. * * *

Most folks are quite happily "weld free" in their dotages, right?
Still, it's a bit of a lump to be prohibited from practicing a skill
and activity I've enjoyed developing over decades and frequently find
useful in my shop. *Oh **** oh dear, poor me.

I intend to wallow in this for a while, **** you if you can't take a
joke. *I'm not happy about this, but it's no secret *that gettin' old
ain't for sissies. * *

Hey Don, you might want to read this.

TMT

http://news.yahoo.com/s/ap/20090115/...edical_devices

High risk medical devices escaped close review
By RICARDO ALONSO-ZALDIVAR, Associated Press Writer Ricardo Alonso-
zaldivar, Associated Press Writer Thu Jan 15, 6:35 pm ET
WASHINGTON – Some medical devices for sensitive uses, from certain hip
joints to a type of defibrillator, have won government approval
without a close scientific review, congressional investigators said
Thursday.

Although Congress ordered the Food and Drug Administration years ago
to resolve the issue, the agency approved 228 medical devices without
a full scale review from 2003-2007, the Government Accountability
Office said in a report.

Some devices approved under the less rigorous process have been
recalled because of malfunctions and other problems, according to the
consumer group Public Citizen. One device was an external
defibrillator to assist heart attack victims.

The report comes as the FDA's Center for Devices and Radiological
Health is the subject of allegations that scientists were pressured to
approve medical machinery against their professional judgment. Nine
FDA scientists wrote the Obama transition team last week complaining
that a "corrupted" review process is putting public health at risk.

The allegations are a separate matter from the concerns raised in
Thursday's report. But taken together, they probably will raise the
level of congressional scrutiny over the FDA's medical devices branch.

"GAO's investigation confirms my concerns that the approval process
for medical devices is woefully inadequate," said Rep. Frank Pallone,
who heads the House Energy and Commerce Committee's health panel. "For
years, Congress has required high-risk medical devices to undergo
stringent premarket review, but GAO's findings show that is simply not
happening in every case."

Pallone, D-N.J., said he intends to hold hearings on the FDA's
oversight of medical devices. The GAO did not look into whether any
patients were harmed as a result of devices that got less government
scrutiny.

The root of the problem seems to be that the FDA never fully carried
out the intent of a decades-old change in the law.

Medical devices include everything from tongue depressors to silicone
breast implants and pacemakers. In 1976, Congress set up a three-
tiered classification system for devices.

Manufacturers of low-risk devices such as bandages and reading glasses
could get cleared by notifying the FDA before going to market. High-
risk devices such as pacemakers and heart valves would have to go
through tighter scrutiny, and their manufacturers were required to
provide evidence of safety and effectiveness. Devices classified as
high-risk tended to be ones that are implanted in the body or could
spell the difference between life and death.

An exception was carved out for new versions of high-risk devices
already on the market.

Manufacturers could get approval by convincing the FDA that these
devices were "substantially equivalent" to their precursors. In 1990,
Congress ordered the FDA to end the practice, but it has continued
even as generations of technology have come and gone.

The report urged the FDA to promptly resolve the problem, either by
carrying out full reviews or reclassifying some devices as lower risk,
if appropriate.

The FDA acknowledged the problem, but has not set a timetable for
resolving it. "In general, we agree with the conclusions and
recommendations," said spokeswoman Karen Riley. "We are considering
legal and procedural options to accomplish this objective."

The GAO report found that two-dozen distinct types of devices approved
without close scrutiny, including metal hip joints, external
defibrillators, and electrodes for pacemakers.

"It all adds up to less-than-rigorous device review, and it's placing
tens of thousands of Americans at risk," said Peter Lurie, deputy
director of Public Citizen's health research group.

___

On the Net:

GAO report: http://tinyurl.com/73nyhl

On Jan 16, 12:43*pm, Bruce L. Bergman
wrote:
On Fri, 16 Jan 2009 00:34:13 -0600, Don Foreman

wrote:
Had another thought today: *

Perhaps the young doc hasn't yet encountered a patient who has
expertise in a related field and doesn't yet know how to deal with
that. *It's not uncommon among highly-educated young *chargers. I have
ample experience with smoke, feathers, fancy dancing and
bafflebull****. * I didn't deal with medical folks during my working
life but I dealt with plenty of high-talent young PhD's in science and
engineering. * *

* You are throwing a big EMF and RF wrinkle into the system that they
never thought of during initial testing and field trials, and doesn't
come up all that often in use - They simply expect all of the grateful
recipients of their medical largesse to meekly back down and give up
all activities that would add the slightest bit of extra hazard,
including an irrational severe allergy to microwave ovens.

* They don't know you very well, do they? *;-P

* Don't feel bad, that's the same faulty logic behind the "No 2-Way
Radios or Cellphones in the Hospital" decrees. *Rather than study the
potential conflicts and determine limits that are technically
required, a blanket edict is a whole lot easier and faster.

A conversation with a decades-experienced "device nurse" was
enlightening.

She said that the doc would not adjust parameters in an attempt to
optimize compatibility with welding, he would adjust them to optimize
performance for the medical purpose required and intended. *

Well, duh! *That's exactly what he should do. * Welding is optional,
dead guys don't need to weld. *I could fault the young Doc's
people skills but I gotta respect a no-compromise attitude re doing
what is medically best whether I like it or not. *That places
responsibility for risk of welding *squarely upon me, which is exactly
where it belongs. * * *

* Dead guys can't weld anymore, yes. *But guys who can't weld anymore
might as well... *No, let's not go there any sooner than we have to.

* They have to look at this as a Quality Of Life issue, and your task
is to beat that fact through their heads. *With their own arm.

* If nothing else, get some hard numbers on limits, and get them to
sign off on your sensor suite to measure them real-time. *You are
developing a new study group, one researcher and one patient. *No
rules that they can't be the same body.

* You might end up with a vest that has sensors and a big buzzer -
when the sensors go over limit the buzzer goes off, it's time to
reposition the weldor, the work and/or the cables.

* And there is always that mule-kick internal alarm if the external
one doesn't work - that should provide impetus to get it right the
first time.

* -- Bruce --

Don't feel bad, that's the same faulty logic behind the "No 2-Way
Radios or Cellphones in the Hospital" decrees. Rather than study the
potential conflicts and determine limits that are technically
required, a blanket edict is a whole lot easier and faster.

You need to take that one seriously.

Transmitters DO affect hospital electronics.

They do that because it is cheaper to enforce a ban than to buy all
new electronics..if they are available.

Another thought...Miller makes a low end TIG welder specifically for
hospital environments.

TMT