Stop Sweaty Hands and Feet With Sweat Fighter!

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About: Writer for Hackster.io, Hackaday.com, and others. Author of Idiot's Guides: 3D Printing.

3/1/19 Update: Some people are reporting pain, which is caused by the quick polarity reversal. I will update the code to reduce that problem, but for the time being you should hold off on building this.

Hyperhidrosis is a condition that causes excessive sweating—even when sweating isn't called for. It can cause sweating anywhere on your body where you have sweat glands, and the exact location just depends on the individual. But, in my case, it's my hands and feet.

Everyone's hands and feet sweat, of course. But, with hyperhidrosis, it's a lot of sweat that doesn't happen for any real reason. It's not dependent on temperature or nervousness, though those can increase the severity. As you know if you suffer from this condition too, it's embarrassing and can make basic tasks like using a touch screen difficult.

That's where Sweat Fighter comes in! This is an iontophoresis machine that treats sweaty hands or feet by sending an electrical current into a pan of water, through your body, into a second pan of water, and back to the machine. I know it sounds like hokey pseudo-science, but it's a real treatment. Commercial iontophoresis machines are just expensive, and Sweat Fighter only costs about $30 at per-unit component prices.

Sweat Fighter has a couple of advantages over traditional DIY iontophoresis machines:

  • Easy to use
  • Timer functionality
  • Automatic polarity reversal
  • Looks a bit nicer

Just plug it in, set how long you want the treatment to last, and press start!

Safety Notes:

  • I am now recommending you use a 12V battery like this one: https://amzn.to/2SlmIT8 instead of the 12V power supply. This will eliminate any potential risk caused by defective power supplies. Simply connect the battery instead of the DC power supply jack. Don't recharge the battery while using the device.
  • This sends a small amount of electricity through your body. It shouldn't be painful or harmful at all, but isn't suitable for people with pacemakers. If you have a heart condition or pacemaker, talk to your doctor before using any iontophoresis device.
  • Someone has pointed out that aluminum pans may pose a health risk. I'm unsure of how to verify that, and commercial machines often use aluminum. But, to be on the safe side, you can use food grade stainless steel pans.

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Step 1: Parts and Tools

This is a pretty simple device, and only calls for a few components. It does, however, use a custom PCB that I designed. The KiCAD/Gerber files are provided (in the .zip folder) for you to make your own, and should only cost about $6 per unit through a service like OSHPark.

  1. Custom Sweat Fighter PCB ($6 per unit)
  2. Arduino Nano V3.0 5V ($4.67 per unit)
  3. L298N Dual H-Bridge Motor Driver ($2.47 per unit)
  4. 128x32 I2C SSD1306 OLED Display ($5.49 per unit)
  5. 12V Battery ($18.21 per unit)
  6. 2X Momentary Push Buttons
  7. Wires
  8. Header Pins
  9. Cables with Alligator Clips
  10. PLA
  11. Metal Pans

Here are the tools you'll need:

  • 3D Printer
  • Soldering Iron
  • Wire Cutters
  • Computer (to upload Arduino code)

Step 2: How It Works

Check out the video for a demonstration!

The dual H-bridge motor driver is doing most of the heavy lifting here. The purpose of an H-bridge is modulate the power going to an electric motor, and to reverse it so that the motor will spin in the opposite direction. We're only using one side of the "dual" part of the H-bridge, and only using it to reverse polarity in the circuit. Reversing the polarity makes it so both hands are being treated.

This particular H-bridge accepts the 12V from the battery, which is what it outputs to the pans. It also has an onboard 5V regulator to provide power to the Arduino.

The Arduino, in turn, tells the H-bridge when to turn on and off, and with what polarity. The provided code lets you switch between treatment times (5, 10, and 15 minutes). The OLED display shows your selection, and a progress bar to let you know how far through the treatment you are.

Finally, the custom PCB ties the rest of the components together, and is where the time and start buttons are located.

Step 3: Print the Enclosure

You should start with the enclosure, because it will take some time to print: about 3 hours for the bottom part and 2 hours for the top.

Both parts should be printed in PLA with the following settings:

  • 0.15mm layer height
  • 20% infill (grid)
  • No supports

Step 4: Upload Arduino Code

Before you upload your code, make sure you have the Adafruit GFX libary and the Adafruit SSD1306 library installed.

Some Arduino clones, like the ones are I linked to, have different driver requirements than genuine Arduinos. Be sure to check the manufacturer instructions if you have any issues uploading the code.

Just open the provided code, and upload it. No modifications should be needed.

Step 5: Solder Connections

The custom Sweat Fighter PCB is labeled, so soldering the connections should be easy. Components should be placed on the same side as the corresponding label.

When placing the Arduino, make sure the side with the USB port is turned towards the "USB" label on the board—it won't work if you use the opposite row of pins.

When soldering the OLED display, use four male headers pins, so there will be a space between the custom PCB and the display

The five wires going from the H-bridge to the custom PCB should be just long to reach. Place both boards in the enclosure to get a feel for how long the wires should be. You can remove the "Enable B" jumper from the H-bridge, as we won't be using the B side of the board.

Two wires should go from the battery, through the hole on the back, and to the custom PCB. Ensure that the polarity is the same as marked on the board.

Finally, there is a spot marked "Power Button." I decided not to use a power button, and so I just bridged that connection (see photo). You could use a power button if you'd like, but you'd need to modify the enclosure.

Step 6: Assemble Everything!

Before you place the boards in the enclosure, take your wire with alligator clips and cut it in half. Feed the two wires through the small hole in the bottom piece of the enclosure, and attach them to the "A Side" screw terminals of the H-Bridge.

Then lay both boards down on the mounts, but take care to make sure none of the wires are binding. Finally, use small screws to anchor them. Place the top half of the enclosure, and place screws on the bottom to secure it.

Step 7: Using Sweat Fighter

To use Sweat Fighter, simply fill the two pans with water and attach the alligator clips to them. Connect the battery, and the device will automatically turn on. Use the button on the right to change the treatment time, and the button on the left to start the treatment cycle.

Once you press the start button, place your hands in the pans of water. Try not to touch the bottom of the pan, as that will make the treatment less effective. You should feel a very slight electrical tingling, but it should not be painful. If you can't feel the tingling at all, your water may be too soft (not enough minerals), so try adding some Epsom salt.

Then just wait for the treatment to finish, and you're done!

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    47 Discussions

    None
    eccomando

    2 months ago

    @cameron coward
    I'm trying to make it but when I use it I feel an electric shock when the current reversing.
    can you help me how to adjust time duration
    The reverse polarity program?

    help me please, I really need this thing to stop my hyperhidrosis.

    1 reply
    None
    CameronCowardeccomando

    Reply 2 months ago

    Hello! I have modified the code. Try the new version (SweatFighterV2.ino). Hope that helps!

    None
    nagabuto0303

    5 months ago

    Hi everyone, I'm very new to do this kind of DIY, so that I need help!
    For the following two parts, which specific ones do you recommend me to buy?
    1. Wires
    2. Header Pins
    I'll be able to try makings this device once I know that. Thanks in advance!
    None
    maxb981

    7 months ago

    Cam, nice work. You provided a fantastic little product for DIYers. However, as you provided instructions for a medical device that people will use on their own bodies, and they trust your instructions, I have a few concerns that I hope you address to improve the safety and comfort:

    The instant the polarity changes is extremely painful and shocking. I do not know if you have personally felt the potential difference once the automatic polarity switches, but it feels like a very sharp electric shock. Obviously a 12 volt lithium ion battery isn't going to be providing enough power to kill (perhaps burn), but it is not the power that is causing the pain, but rather the rapid change in polarity that causes the extreme pain. I am wondering if you could respond and help provide additional code to:

    A.) Slowly fade the voltage to 0 and then ramp the voltage up SLOWLY in the opposite direction

    B.) Offer users an ability to remove the automatic polarity reversal all together, so that they can do it manually with the alligator clips

    Other than the painful shock that comes from the "automatic polarity reversal", this project proves effective in obtaining the goals of beneficience to the patient with low harm to the patient. Until the code is addressed to provide a solution to the painful polarity reversals, I see myself using my lithium ion 12 volt battery with alligator clips as it is safe and more comfortable than this project.
    1 reply
    None
    CameronCowardmaxb981

    Reply 7 months ago

    Thanks for the comment! I myself didn't notice it being painful, but everyone is different and someone else had pointed out that they experienced pain as well. You are absolutely correct that it's the potential change that would cost that, and the fix is to switch it gradually. I'm in the middle of a cross-country move right now and can't update the code at the moment. So, for now I will unpublish the project. After I can update the code, I'll put it back up. Thanks again for the heads up!

    None
    starphire

    10 months ago

    It's really troubling that you are not responding to comments. PLEASE change your power supply for one that only uses batteries, or at least uses a decent quality isolated DC power supply. Unlike the heavier old style wall transformers, modern and cheap DC wall supplies like the one suggested here are known for sometimes having one of the AC pins connected directly to the DC output - super dangerous! Sometimes there is nothing but a diode to isolate it from the AC, or a tiny gap on the PC board between AC and DC side that can easily arc over. Designers of these cheap adapters are not following strict safety protocols but instead designing for smallest size and lowest possible cost. They are not expecting these to be used for potentially dangerous applications like this. They should NEVER be trusted to have their outputs in contact with human skin. A GFCI outlet is not an adequate safety measure, either.

    3 replies
    None
    CameronCowardstarphire

    Reply 10 months ago

    Hi starphire, I have been responding to the comments, but I apologize if I've missed any. Why is a GFCI outlet not adequate? Isn't that what they're supposed to protect against? In any case, I'll rewrite this to use a battery only. I certainly don't want anyone to be put at risk.

    None
    starphireCameronCoward

    Reply 9 months ago

    I didn't see your other comments, just noticed that there wasn't a reply to recent ones that brought up the same concern. A GFCI is intended to be a secondary backup for normally safe devices that could become unsafe under certain rare conditions. A good idea to have them, but they're not foolproof: they have a moving part that could get stuck, or
    fail to trip. If it's on a reverse-wired outlet (hot is on neutral and vice versa, surprisingly common in houses with old wiring), a GFCI may not work at all. Basically they're not something I'd want to rely on for daily use of a product that *might* be inherently unsafe for this kind of use.

    Unfortunately the current state of the market with these plug-in switching DC supplies is pretty hit or miss as far as isolation and spacing between primary and secondary parts of the PC board go, and cheaper ones are rarely certified for safety by the more rigorous testing labs. Factories may substitute different circuits into the same housing without warning, so two customers might not even get the same thing inside.

    None
    CameronCowardstarphire

    Reply 9 months ago

    I see. Thanks for the explanation. I've updated the text to say to use a battery. It's not as convenient, but convenience isn't worth that kind of risk. Thanks again!

    None
    Censo

    10 months ago

    With systems connected to human body you absolutely must use full galvanic isolation to avoid electrocuting. It does not matter what low voltage the system uses, difference of potential between electrodes and grounding can be high enough to kill you, especially if power supply malfunctions or does not follow strict guidelines. People died even from using phones being charged https://www.vice.com/en_au/article/pa5mng/a-16-year-old-has-died-after-being-electrocuted-by-his-headphones

    4 replies
    None
    CameronCowardCenso

    Reply 10 months ago

    Wouldn't that risk be present for any device plugged in with a questionable power supply? Plugging it into a GFCI should be a sufficient precaution, correct?

    None
    CensoCameronCoward

    Reply 10 months ago

    Yes, the risk is with every power supply connected to AC outlet, however in vast majority of cases we are isolated from wires by device plastic case. It is quite different with medical devices connected to human body. There are strict requirements on galvanic isolation and usually medical devices use old style transformers in PSUs. Also, there are optocouplers on USB lines and so on, some related documentation can be found here https://www.edn.com/design/medical/4314949/Designing-medical-devices-for-isolation-and-safety
    Adding a note about GFCI is great, it is a must, not sure if it sufficient though. You may also consider battery powered solution to avoid AC altogether.

    None
    crfgarciaCenso

    Reply 10 months ago

    Battery powered seems safer, and it makes it portable.

    None
    CameronCowardCenso

    Reply 10 months ago

    Thanks for the information. This can easily be adapted to use a 12V battery, I'll add a note about that too.

    None
    beta35

    10 months ago

    Hello,
    Aluminum is a hazardous metal for health if you use it during iontophoresis. I see that you have used aluminum pans as electrodes on the video. After some time of iontophoretic activity, there would be pores on aluminum, probably most of them penetrated into the tissue through the water.

    5 replies
    None
    CameronCowardbeta35

    Reply 10 months ago

    Do you have a reference for this? I've never heard of aluminum being an issue, and commercial iontophoresis machines use aluminum.

    None
    beta35CameronCoward

    Reply 10 months ago

    Aluminum is a soft metal, which is not resistant to acid or alkali. Current through water will electrolyze water to hydrogen and oxygen that may also cause alkalic or acidic surfaces on both electrodes and sweat glands of the skin. After some time, there will be microscopic pores on aluminum surfaces because of electric current flow. That means aluminum surface was eroded and the aluminum gone to the other electrode surface (cathode) through some physicochemical reactions. The skin surface so the sweat glands are act as a cathode electrode surface on anode aluminum electrode. Aluminum is the only metal that the body does not have even rare amounts as other metals. Aluminum is also a well-known toxic metal especially to nervous system (https://www.ncbi.nlm.nih.gov/pubmed/26922890). By the help of electric currents, you are forcing aluminum to enter the body more than its usual exposure regime, if it is an electrode. Best and safe method of should be medical grade stainless steel (316 or 318t) because they ae more and more durable to acid or alkali. According to my experience, they do not have any microscopic pores if we were use years and years continuously. The only problem with these medical grade stainless steel electrodes is the collection of water lime on one electrode surface while the other is shiny. I never recommend aluminum electrodes for hyperhidrosis treatment, as there is a serious risk in long-term usage.

    None
    CameronCowardbeta35

    Reply 10 months ago

    Thanks for the thorough explanation! I imagine a food-grade stainless steel (often 316) should be sufficient then? I'm curious why aluminum is common in commercial machines if it's dangerous. I used to work for medical device companies (as a mechanical designer), and things like that were regulated.

    None
    crfgarciaCameronCoward

    Reply 10 months ago

    According to the Wikipedia Iontophoresis article, tap water can be used in mild hyperhydrosis cases and anticholinergics for severe ones. No mention of Aluminum like in antiperspirants.
    Maybe Iontophoresis can replace Aluminum ladden antiperspirants for underarm use?

    None
    beta35CameronCoward

    Reply 10 months ago

    I recommend medical
    grade stainless steel because I never met any pores on its surface in long-term
    and intense usage in hospital. Food-grade had also pores on very long and
    intense term usage. I think that food-grade stainless steel is acceptable for
    personal usage because it is much more durable than aluminum. I may recommend
    using forks and spoons in the kitchen as electrodes for iontophoresis
    treatment. I do not understand why some medical device companies continue to
    work with aluminum electrodes. Probably, aluminum is cheaper and metal
    processing is easier than stainless steel. Alternatively, the aluminum plates
    that they use may be a different kind of aluminum alloy, which is more durable
    to acidic or alkali reactions as airplane wings and body. Otherwise, there is a
    serious risk in long-term usage. Because it is the electric current, that pulls
    off aluminum atoms from the surface to water, then the resulting ions pushing
    to the sweat glands. Or, there is a point missing in regulations that never considered
    before. Finally, I think that there is a serious risk due to aluminum
    accumulation, if it was used as an electrode on an iontophoresis device and
    this risk may appear years and years later in the nervous system as a
    pathology.