My kinda cool build with an Arduino timer+counter

Hiya everyone,

I bought a one touch about a month ago and proceeded to mod it with the typical sponge anode, foot pedal and I jury rigged the stylus to take normal needles. Then I decided to just build a machine from scratch and added an Arduino+LCD I had lying around that acts as an insertion timer, hair kill counter and a buzzer that pauses every 10s so I don’t have to count 40 Mississippis in my head.

So felt like sharing since I haven’t made a post here yet even though I’ve been reading a bunch here over the last month :slight_smile:

The whole setup:

And it all turned out too be just as much of an eyesore as I was expecting.

The only LCD screen I had lying around was this one, unfortunately I had wired it up when I was just learning how to solder 4 or 5 years ago so it’s kind of a mess and also it’s attached to an Arduino shield making mounting to my ‘case’ close to impossible. So the Arduino just hangs out propped up against the case or on top of it at the moment :). I thought about desoldering it apart and rewiring it but decided to just order a tiny 2" touch screen for $10 (which comes Saturday, yay).

The makeshift needle holder:

To get it to take regular needles I first snapped the two metal shank pieces of a one touch needle apart and then kept the top tubular one and jammed half of one of those plastic tubes sterex needles come with inside. Then I glued the plastic bit to the metal shaft and crimped the metal tube a little bit after where the plastic tube ends. So when a needle is put in the plastic tube holds it snuggly and the crimped metal tube prevents it from being pushed down further and makes electrical contact. However it holds the needle a little too snuggly and pliers are required for removing an old needle. Electrical tape is there to keep it from sliding around when setting it down, not to hold it together.

So my next step is definitely going to be prettying it up, no point in hair removal if you can’t do it in style. Then after I run out 9Vs I might change to this regulated power supply I have from a eurorack synth that has 12v and 5v rails.

Decided to go the cheap DIY route instead of to a professional since I’ve done a bunch of DIY audio and synthesizer projects already and had some circuits exposure in college so modding or making one would be easy for me. Also currently unemployed so limited $$ but plenty of time. Electro has been a bit difficult to learn especially at the very start (and still learning), which I expected, but not extremely impossibly hard as some DIY naysayers have warned.

Great job! I think buying a needle cord would be the way to go. If you live in the USA, I will send you one for free (I have bunches of them) … let me know. Easy wire job and easy screw-off tip.

It’s a clever design with the “probeholder” but Michael is right, a real probeholder will give you better insertions.
With a modification of the power supply, a different probe holder, how much of the one touch are you using? Wouldnt it be easier to determine the approximate power and resistances and put in a better reostat and design your own circuit with a with a pedal contact switch??

But I do give one caution to all of this. Galvanic by itself is extremely tedious. To perform any meaningful hair removal, whether "pretty " or not you’ll probably want to try blend. And for that a galvanic only rig wont do. It’s not the same kind of “DIY” as building your own setup , but DIY from the effectiveness standpoint usually involves an epilator made for professionals which has been retired.

I’m just pointing this out , an elegant and functional galvanic circuit isnt that hard to create. It sounds like you’re having fun with your project, and for that I’m happy for you. One Touches have a bad reputation of burning out though from shoddy components.

Seana

Oh I’m aware of the one touch’s shoddy wiring, I already dropped everything except the probe holder which I also rewired with a sturdier cable. I decided to start off with the one touch as I wanted a working machine in front of me to start to calm my nervousness

Yep I’m in the USA and sure I’ll take you up on the offer if it’s really no problem for you :). I’ll pm my address.

Thank you!

And IMO the actual circuit board components on the one touch aren’t really the issue, the main problem is they used tinsy wire gauge for the stylus and so the cord is very likely to break. The wire is braided though, surprised they didn’t just use solid wire.

So if people with burned out units just rewired the holder they would likely fix the problem.

It seems to me weve heard multiple reports of the variable resistors expiring in a puff of smoke.I didn’t know there actually WAS a circuit board in them but I’ve never attempted to modify one.

Using good quality components it’s possible to build a good circuit, but why do so when a machine capable of more than simple galvanic will be necessary to remove hair with any sufficiency? My point is that you probably want to get a professional unit and put that ingenuity and willingness to learn a new skill into something that will actually get you somewhere.The best advice I ever took from one of the professionals here was to start with professional equipment. And in fact I worked in galvanic alone for a very brief period of time ,literally about a week, before I got fed up with it and tried my hand at blend.I worked almost exclusively in blend for most of 3 years

Yep even has a fancy shmancy TI IC and protection diode

I really don’t mind the slow speed or extra pain of galvanic and call me crazy but it’s slightly relaxing. So far I’ve put in 20-30hrs, I did get fed up with the unmodded one touch in under an hour though and removed it’s very loud and annoying buzzer and added a sponge right away.

Also I like the idea of galvanic for the lower chance of causing scarring if I screw up while I’m doing my face. I’ll probably get to a blend machine eventually. But why buy when you can do something like this: http://www.hairtell.com/forum/ubbthreads.php/topics/45081/Build_Your_own_27_Mhz_Epilator.html :stuck_out_tongue: (don’t know if I trust my electrical abilities enough to try that though)

Added the new screen and old synth wall power supply today and switched to a bigger wood box and a prettier scrap front panel :grin:

way beyond what I could do, so good luck!

That is very impressive !

[Random update, apologies for using this forum as my diary :P]

Yesterday I was attempting to add an adjustable constant current controlled by the Arduino to replace the 12v controlled by the analog pot. Which would help make the power level more predictable as body resistance changes on a daily basis and can vary on insert location too. Think this is also something actual manufacturers have in their machines.

So I was thinking about which random electronic I could scavenge for a digipot when I stumbled on some 5v 12bit DACs in my parts bin, sweet. At only 5v output amplification is required so I used 1/4 of an LM324 opamp to multiply the voltage x2 to get it back up to 10v max which is enough to zap any hair. Then the Arduino has an analog input hooked up to the needle/electrode circuit. This all gives us readings for input voltage, the voltage drop and the resistance of a resistor in a voltage divider going into the analog input so we can deduce the resistance of the person and the current so we can then adjust the DAC output to meet the target current. Cool.

I breadboarded it and it seemed to work out (though powering opamp at only 5v), then I soldered it down to my PCB ANNND screwed up somewhere ughh. My board layout is just a bunch of single holes so have to use solder bridges and the density of the IC pins probably caused a bad joint.

So I need to fix it today so I can continue doing electro :c

Also some rambling observations and things I learned that are maybe helpful for other DIYers [accuracy of information here not guaranteed]

  • Perfect insertion depth and a well fitted probe size for galvanic is not that important as the lye will diffuse around to the right place one way another. This means you can get away with just putting the needle at least a few millimeters and you don’t have to risk going too deep and poking out the end of the follicle if you haven’t developed a good feel for the end of the follicle yet. [And Michael Bono confirmed this for me]

  • It’s really easy to strain your back/neck doing this for any decent chunk of time. So what I do is lower my old office chair all the way down and slide it under my dining table so I’m as close as possible to the edge and I have a couple of text books lying around to lower/raise the height of my magnified mirror. Also I try to tilt the mirror and my lighting as much as possible rather than maneuvering my head or neck.

  • Even at the slower speed of galvanic need to be careful with doing too much in one area esp sensitive areas like the upper lip, a few weeks ago I zoned out a little and spent a couple hours on my upper lip hairs, initially afterwards the area looked fine but later that night it had puffed up quite a bit and I looked like some sort of tropical fish. So spread out and don’t go for clearing an area. [I also have in my head that pure galvanic causes more swelling afterwards then blend but I’m unable to find a source for that]

  • I use this nifty ‘architect’ lamp https://amzn.com/B002ZKDUVE with a 100w LED bulb, the arm can be maneuvered around all sorts of ways so you can get the lighting just right for the area you’re working on (it’s also my soldering lamp).

  • My current rate is about 50 hairs an hour and I can’t imagine going much faster than that (unless I bump my current up). The maximum you can probably get to is 90hrs/hair, using a generous 30sec average hair kill time + 10sec for tweezing, inserting and swabbing lye away.

  • I have a ‘10x’ 6" magnified mirror that has some ridiculous distortion that was nauseating at first for this and is still annoying. Planning on getting a new one when I have the money. If you’re getting a new mirror for this read the reviews and figure out how much distortion it has and also make sure to get one that can tilt

  • The one touch is worthless without modification and I kinda regret buying it in the first place. If you’re thinking about buying one I don’t recommend it unless you’re planning on modifying it and if you’re like me and know some electrical stuff, just skip the one touch and build one from scratch… Learning basic electrical skills and how to solder really isn’t that hard though, probably easier than electro. You can find ‘learn how to solder’ kits on amazon for $15 and it might leave you with enough solder for this project and you also know how to solder now :).

[Boring aside] I do recommend leaded solder though which the kits won’t come with. Lead sounds scary but it really ends up safer. See electronics.stackexchange.com/questions/19077. In short, lead-free can cause more shorts down the road which is why some medical manufactures still use it, lead-free is harder to work with and lead-tin solder doesn’t actually cause significant lead exposure to the solderer.

1 Like

Oops remembered one more

  • I’ve seen some DIYers say they like to zap a few hairs before grabbing the tweezers to speed things up, for me at least I’ve found this just leads to me forgetting which hairs I zapped and tweezer testing random ones till I find a loose one or give up :blush:. I also don’t like leaving any lye that might have come up longer than it has to so may as well grab the tweezers if i’m grabbing my alcohol swab and just tweeze individually.
    There’s also holding the tweezer in the other hand at all times but I imagine it might be too much of a pain to master when working through a tiny mirror on yourself and already struggling to get a good viewing angle and skin stretch down.

  • I saw the one touch manual tells you to soak the needle in alcohol before every use, soaking in alcohol really only sanitizes the needle it doesn’t sterilize it. So if you repeatedly reuse a needle even though it’s only for you it can accumulate bacteria and bacteria spores that alcohol won’t remove which could possibly cause a bad hair/skin infection for you, that .01% of bacteria it doesn’t kill are important too. One touch needles are ridiculously overpriced so you can’t really just use a new one every time though, leaving you with what I feel is the only option of modding it to take professional needles. (You can get ‘eh close enough’ to sterilization at home without an autoclave however by adding pressure cooker, microwave, lighter and bleach soak steps)

Got the adjustable current working :slight_smile: :

quite a bit of this is beyond my own electronics skills but I’ve a few comments anyway:

First, I would consider adding a milliamp meter to measure the exact current being discharged from the circuit to 2 decimal places.This will assist in your calculations of timing and units of lye delivered.

Regarding depth accuracy, I’m going to disagree with Michaels assertation that “just inserting a couple of millimeter is good enough”( and in fact if he did say this, I’m quite surprised! I’m of the opinion you misinterpreted him) . I’d like you to have a look at Michaels recent video on tweezing and how the hair follicle prevents substances from being delivered lower into the follicle than the insertion by it’s physical structure and makeup. This would include lye. Insertion depth is one of the more important skills you can master, and honestly it isnt that difficult.
Chief amoung considerations regarding insertion accuracy is the concept of the “moisture gradient”. All forms of electrolysis, be they galvanic, blend or thermolysis use moisture to accomplish their kill. Moister, wetter skin conducts the currents with greater efficiency.This means moister tissue will convert salt and water into lye with less pain, and create more lye per milliamp of current, and more importantly, create and distribute it to the place where it is needed, that is the bottom of the follicle. The deeper you go into the skin, the denser moisture becomes, creating a “gradient”.What you want to be doing is getting that insulated probe as close to the bottom of the follicle as you can.Yes, if you miss and overshoot you will probably still get enough lye into the upper parts of the follicle. You will not by going too shallow.Instead the smaller amount of lye will affect the upper tissues of the follicle and not penetrate deeper, and likely not kill the cells near the dermal papillae.The easiest way to determine proper depth is by learning how to do a depth guide, after a while you will be able to do it by feel, you will be able to “feel” the bottom of the follicle with the probe. ter a few insertions with galvanic you wont need this crutch as the lye crust will indicate the previous ( correct) insertion depth.

One of the advantages of “treat and wait” ( treating many follicle and then removing at once) is the lye has more time to work in the follicle. Yes, it’s possible you may forget which hairs you have treated, but this should become immediately obvious when you go to tweeze the hair. If it hasnt been treated, tot he correct depth and with enough lye for enough time, the hair wont release.If a hair is not releasing, it should NOT be plucked out forcefully. The correct approach is to treat the hair until it does properly release. With time you will learn to treat smalll groups of close hairs, so you dont forget which ones you’ve treated and which you havent.

Regarding holding the tweezers in one hand and the probe holder in the other, I wouldnt try to do this with DIY in the face. Learning to “switch” between tweezers and probe single handed ( while using the other hand to stretch the skin, will become an important skill.I dont feel the 2 handed epilation is suitable for doing DIY on the face it’s awkward and will worsen your accuracy. It’s fine when working on someone else, but working in a mirror with reversed movements it makes things too difficult. I personally like using peer vigour size 0C tweezers for one handed epilation because I find the switching back and forth very easy to accomplish with practise.

Regarding positioning, I think you are on the right track, but I would be willing to bet your back is aching something awful after epilating for a while . Your positioning and ergonomics will absolutely dictate how long you can work, how efficiently you can work, and with what accuracy. You want the least stress on yourself as you possibly can and the best positioning possible. So here’s my “recipe” for DIY positioning. When working on myself, I lay flat on my back. No craning of the neck, no bending over, no stress on the spine. A bed works fine lying down, a old weight bench, an aesthetics bench ( with the pedal on a chair next to it) . Then hang your foot over the side to reach the pedal. For vision a magnifying mirror hanging from the ceiling, or one stuck to the middle of a circle lamp magnifier, will allow you to get your vision aid right where you need it. The hanging it from string approach does have one disadvantage, that is if you knock it ( and you will) it will swing and must be steadied often. But this positioning will allow you to work, comfortably , for long periods without a lot of stress on your back , neck, or spine.

For sterilization, you are essentially talking about tweezers. You dont need to sterilize probes because they come pre-sterilized. At about $1 a probe it’s not worth it! As a DIY’er you arent exposing your tweezers to some of the more dangerous bacterial contaminants so you have some leeway here. I used to boil tweezers when working on myself, and while insufficient for work on others, this was fine for just working on myself. The pressure cooker idea works well ( make sure you get a heavy enough weight for it) . A ( new) toaster oven at high heat can work. Or if you like I have a dry heat heat sterilizer I could sell for very little, as it doesnt have a external temperature guage it doesnt meet ontario regulations for commercial use, but is perfectly functional and fine for at-home use.You could also use “quat” or a hydrogen peroxide soaking for this purpose.

Seana

Probably misunderstood a PM? … but YES … you must insert the needle to full-depth of the follicle (over-shooting is better than under-shooting). Thanks Seana for noting this … and, I like all your comments too on this subject.

(Seems like a LOT of electronics just for a simple DC circuit. I made one with a 9V battery, a “pot” and a DC meter. And, of course, a positive wire and needle cord.)

Meese, did the needle cord and needles get to you?

Think you missed my second set of images. At the bottom of the screen it’s showing the dialed in current of 500uA and 750uA on the bottom image and my multimeter results which show 500uA and 740uA (my multimeter’s margin of error is around 10uA so giving benefit of doubt to my circuit).

So the circuit can be thought of as having a built in current meter that then adjusts the voltage to get the desired current that is selected with the + and - buttons on the screen. (Or more precisely it measures the voltage drop across the person to figure out what their resistance is to figure out what the v in V=IR to get the desired current). Which is much preferable to having a multimeter out tangling things up and manually adjusting an analog pot. With an analog pot one day you could be getting 500uA and another day at the same position it will give you 600uA.

that’s more than likely

Haven’t checked my mail yet

Yep I know, I was talking about how if another DIYer attempted to use just the one touch probes which are cost inefficient to replace every session and how the way one touch tells the user to clean them isn’t 100% safe.

A very large percentage of the population are carrying some strain of staph bacteria at any given time(Like 20%-30% of people IIRC, although it’s a smaller percentage of that which are ‘dangerous strains’), which is fine unless it gets direct access into parts of your body it’s not supposed to be regularly. So it would be trouble if you have some staph chilling in your nose and you sneeze and a tiny amount escapes your hand/elbow block and then floats onto your needle.

Yep I’m aware and already do it progressive only tweezing fully when it wants to come out like. If I forgot which hair(I have a terrible memory) and also undertreat it makes it a big pain to figure out since I have to find the one that feels kinda looser than the others in the area which can be impossible.

I have varying shades of red and blonde and their easy for me to mix up which color they are unless the lighting is just perfect. My usual mix up is with these dark red coarse-ish guys that take a minute(+) and these medium blonde coarse-ish guys that take around 40 seconds. So I go 30-40sec for the initial treatment of most coarse hairs which causes me to undertreat more and makes doing a few and then tweezing less productive. Though maybe I just need to get better at figuring out what color a hair is…

Yeah I saw a post about that doing it while on your back (probably your post) and I might try it out soon, more for the possibility of better viewing angles and lighting. Less concerned about the back stress as with my current setup is basically the same as sitting in a chair and looking at a computer screen, as long as a resist moving neck instead of moving my mirror and lamp around. As a software dev I normally already have to do this 8-12 hours a day so adding a 1-3 hours every few days isn’t going to hurt my already screwed back much more.

Sorry I was half awake when I wrote that this morning while having my coffee before dashing to work:) yes I missed viewing that image.

The point I was trying to get across re: sterilization.

It’s pretty much un-necessary.

As a DIY’er, you will not be using your tweezers for anything which will penetrate the skin. The probe does , yes, and if you have concerns about bacteria like that on the skin you should be wiping the area down with alcohol or witch hazel first. However transmission from your tweezers ( which grasp the hair and dont break the skin like we pros might do removing an ingrown hair) dont need to be sterilized.I cant count the number of times I simply washed my tweezers between treatments. It is only when I started working on others that sterilization in any way became a priority. Unless you are routinely jabbing holes in your face with your tweezers ( and in that case should rethink your methods) sterilizing them wont do any good whatsoever. Really!

Seana