Reviving an AutoDarkening Welding Helmet

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Introduction: Reviving an AutoDarkening Welding Helmet

About: Engineer. HW/SW development tools. https://patents.justia.com/inventor/lee-studley

Reviving an AutoDarkening Welding Helmet:
As an Instructables virgin, I decided to get started with sharing my experience with my Harbor Freight Auto-Darkening Helmet resurrection.

I use my mig welder all the time for quick fabrication of brackets etc. One day
I went out the the shop, fired up the welder, and donned my welding helmet. I then proceeded to start the weld and was surprised by the flash intensity. My auto-darkening helmet had always stepped in and attenuated the bright welding arc, but this time it didn't.

My quick test then was to go outside with the helmet, look at the sun indirectly through the welding lens, while waving my hand in front of lens to create a variation in light hitting the front and sure enough, the lens darkened, but faded back to clear in a second or two.

Items required:

- A welding helmet that needs fixing of this sort.

- A dremel tool with arbor and abrasive cutting disks( or diamond wheel types )

- Hot Glue gun and glue sticks

- A soldering iron and solder

- 4AAA or 4AA batteries.

- Qty2 2-Cell holders( =3VDC ) for the batteries selected above.

Step 1: Finding and Exposing the Battery

On the front of the lens casing, at the top, there appears to be a solar cell.

Over the years I had assumed naively that the helmet recharged over time with ambient light. (Edit: as member::DerStu pointed out, It turns out it does trickle charge if left out in sunlight.)

From experimentation I found that there are 2 additional photo sensors( either photodiode or phototransistor based ) that sense and maintain the darkened state of the lens.

I decided then that there must be a battery or storage super-capacitor inside the lens that had died. Since the lens's plastic casing is approximately 3/8" thick, I guessed that it must use a coin cell type and looked for a reasonable location where they could have placed one.

I broke out my trusty dremel with my favorite attachment: A wheel arbor with a thin abrasive disk. This combination is very useful for all kings of fabrication and dissection of things. (Tip: look up images of "Riemann Sum" and you get the idea of one grinding technique to approximate shapes )

As seen in the picture, I was lucky to find a coin battery on the first try. Using the dremel tool with a pinky finger or two for support on the table, cut out a shallow ( at estimated plastic depth ) square shape approximately postage stamp-sized. Keep the square cutout piece of plastic to use later. The battery should be exposed. At this point make sure you identify and record the battery lead locations and polarity.

Take a small thin bladed screwdriver or precision nippers, carefully, as close to the battery 'weld's, pry the battery tabs upward to break them loose from the battery. Do not put so much stress on them that you break the tab leads at the location where they connect to the PCB. The underside of the battery is harder to work loose, but with patience and control the coin cell battery will cut loose.

Now go out and get qty:2 2xAA or 2xAAA battery holders and qty:4 AA batteries from RadioShack or similar. The emphasis on qty:2 of these holders will be explained later.

Step 2: Adding the External Batteries

Next solder the 2xAA battery holder leads. Red lead to the positive marked lead where the CR3023 battery was connected.


Then do the same procedure with the Black lead to the minus(gnd) marked lead where the CR3023 battery was connected. Cut a slot in the LCD case so that the holder leads can be routed outside the case. Hot glue the wire leads, slot, and glue cutout cover plastic you saved back into place. To break the suspense, I thought I was done at this point, but after tossing in batteries and welding, I found that the darkening attenuation at the dark-most setting of the lens was not what it used to be.

Short_tangent_rant: At this point I got on the internet and did a search to see if anyone else had tried this. I like to reason out and try things first before resorting to Google. This way I have to use my own creative muscles first, before using another person's brain power. This can be both good and bad in that often you can learn from others trial and error before doing a task, but if you always resort to others to tell you how to do things, you don't work through the "eureka" discovery process that can often lead to new and novel ways of doing things. End_Of Short_tangent_rant.

I found some links where people had found a 2nd battery on opposite side of the lens, but they couldn't explain its purpose or why it usually still had reasonable life in the battery. I can clear this up. The first battery powers the analog circuitry( op-amps etc ) that process the light levels an then control the drive to the LCD of the lens that darkens. The 2nd battery is the contrast voltage for the LCD and is responsible for how dark the lens can go. Contrast voltage to LCDs are extremely low current draw so this battery is often still usable.

Contrast voltages are sometimes negative with respect to the other circuitry and this is the case here. The two coin batteries are wired in series, with the first battery's negative connecting through the PCB to the 2nd battery's positive. This creates a bipolar supply +3vdc/-3vdc for both the analog processing and contrast circuits.

So after dremeling the case to expose and remove the 2nd battery, using the same procedure as the first battery revamp, I put in the 2nd set of AA's into the 2nd holder and mounted them inside the helmet above the lens.

I recommend to use Velcro with really good adhesive that wont slide off over time. Liquid Nails item called "Perfect Glue" in a tube is one of the best clear adhesives around. It's not Vinyl bases, but like stiffer silicone on steroids. I used coated Romex wire in a pinch to wrap them in place.

Step 3: Conclusion and Test:

Using the "sun" test mentioned above, I found the helmet worked perfectly and has been in use
for 2 years now without issue.

Good luck, Be Safe, and Have fun Hack-Making

-Lee Studley 20141210 Merry Christmas and holidays to all

I'd like to thank author: HollyMann and others for their inspiring Instructables and creative sharing.

Disclaimer: This instructable involves the use of power hand-tools, electricity, and soldering. If you are not comfortable using these items, then refrain from doing so. I'm not responsible for what and how do after reading this instructable. If you disagree with this instructable or any items therein, please feel free write an instructable reflecting your experiences.

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    55 Comments

    0
    DerStu
    DerStu

    6 years ago on Introduction

    I have the same hood which I let sit for about 5 years and mine does charge via the solar cell, but it's a trickle charge, and takes quite a while to recharge I wonder if your photo sensors were blocked from the fumes as I was having a similar problem while tig welding and charging the hood under a light fixed it for me either way rewiring it with replaceable batteries is awesome

    0
    studleylee
    studleylee

    Reply 6 years ago on Introduction

    Agreed. I did clean the sensors while I was doing the modification. They were dusty.

    I did leave the helmet in the dark shop most of the time, so that was partly the cause too.

    The coin batteries would take a charge at a slow/low rate so that makes good sense.

    Cool, I hope it goes well.

    0
    John T MacF Mood
    John T MacF Mood

    Reply 4 years ago

    Coin batteries aren't actually designed to take a charge, so you got lucky there...

    0
    John T MacF Mood
    John T MacF Mood

    Reply 4 years ago

    Most coin batteries are throwaway and not rechargeable. (Dispose of properly!)

    2
    twitting
    twitting

    6 years ago

    An easy way to test an auto darkening shield is with a cheap (e.g., bic) lighter. The sparks from the flint striking the thumb wheel should make the shield go dark momentarily. You don't light the lighter...just flick the thumb wheel a few times.

    Thanks for the write up...I'm sure I'll need to do this at some point.

    0
    John T MacF Mood
    John T MacF Mood

    Reply 4 years ago

    I assume the spark from an oxy-actelene rig lighter would do the same as a "Bic" or better.

    0
    simonrafferty

    Thanks for the Instructable! I have a (expensive) ESAB helmet which has stopped working. I couldn't bear to put it in the trash and had planned to investigate. At least I know what to expect now!

    0
    studleylee
    studleylee

    Reply 5 years ago on Introduction

    That's great! If you have time take some pictures and post them in the replies.

    I'm adding a 2nd instructable to add a minimum filter and an LED headlamp for the users concerned about the fractional milliseconds of flash before the lens darken.

    0
    John T MacF Mood
    John T MacF Mood

    Reply 4 years ago

    Wise idea sir, radiation exposure is cumulative, and sooner or later, the retina will be permanently scarred.

    0
    John T MacF Mood
    John T MacF Mood

    4 years ago

    Great hack! One doesn't want to take chances with vision, that blindness would kind of end any kind of project building for me...

    This one I'm filing way for future reference. I may modify a new welding helmet from Harbor Freight. Yes, I do buy there, but only select items, a lot they sell isn't worth the money, even at their "bargain" prices.

    The battery hack is applicable to computers, read on...

    I have little to no confidence in the common CR-20132 and similar which I HAVE to use in my computer. In watches, they always fail at the most inopportune moments, one of Murphy's Laws sub corollaries, no doubt. A set of alkalines replaced every 6 month or so dust cleaning cycle would definitely do the trick for my computer. Once my motherboard is out of warranty, I'm changing over. Some of the earliest computers I worked on had a four cell "AA" pack rather than the CR-2032. I've been a computer tech for almost 40 years. Some Altair builders used this as a "mod" to the original kit/plans. If you never heard of an Altair, you're too young.

    I run a fairly "hot" processor, and it will force a shutdown if you reach 80°C (Athlon 4100 series 3.6 gigahertz.) I keep a temperature monitor on screen, and clean the dust whenever the temp starts to climb and clean and replace the heat sink compound. I'm at 37°C right now (98.6°F) so it's relatively cool. (Yes, I build my own PC's) I haven't bought a retail desktop since 1982. Laptops just don't seem to come in kit form. Intel chips will also throttle back and stop running in a similar fashion, to prevent "core meltdown".

    0
    joshiii92
    joshiii92

    Reply 3 months ago

    These filter won't give you a flash if they don't change. They just block the brightness.

    0
    joshiii92
    joshiii92

    3 months ago

    Sunlight is good for charging an ADF but not for testing. While it may still change, sunlight is too 'smooth' for the sensor to reliably detect, so maybe not good for reliable testing. It's the same reason why some ADF's not designed to won't work with TIG welding won't change, the arc is too smooth.

    Someone else here suggested a lighter, this is a good way to test.

    Also, ADF's have permanent filters to prevent you from getting a flash, even if the filter doesn't change, the auto-darkening filter just drops the brightness.

    0
    MarkC157
    MarkC157

    4 months ago

    My kobalt helmet had external 2032 batteries. It would not get dark enough. I replaced them and it still didn't work right. After reading about the +3\-3 supply, I wondered if the batteries I put in were good. Sure enough, one tested at 2.8 volts. Between that and setting it in the sun for a couple of hours, it works fine now.

    0
    studleylee
    studleylee

    Reply 4 months ago

    Very Cool and good debugging!!!! Yep, mine has been going for years now.

    0
    cork_cm
    cork_cm

    1 year ago

    Does anybody know if the cells are in series and this runs off 6v or the cells are parallel and it runs off 3v?

    0
    KYHighlander
    KYHighlander

    Reply 1 year ago

    2032 batteries are 3 volt. so, I assume you would need to do them so they produce 3 volts.

    0
    studleylee
    studleylee

    Reply 1 year ago

    On mine: they are in series to make a+3v and -3volt supply with gnd as the common connection.

    0
    RyanB426
    RyanB426

    1 year ago

    I was wondering what I could do with my welding helmet it was my grandpas and it sat for about 12 years I would say I have cleaned to the best I can and the auto darkening lens does not work and i was wondering what i could do because it is such an old helmet i want to try to keep it as original as possible

    0
    studleylee
    studleylee

    Reply 1 year ago

    You're going to have to take the plunge and try. Does it look like the one I or others have shown? Is the lens module removable like shown? Try to pry it apart carefully as others have found some are not glued as strongly as mine was. At worst, you can buy a new module, or a helmet to scavenge and repair this one for sentimentality. I have tools from my pop that bring back many good memories, so I understand that very well. Try.