My kinda cool build with an Arduino timer+counter

Hair Removal Methods Do-It-Yourself Electrolysis
#21

Yep just got it, Thanks again! I’ll try it out in a little after I scrounge around for a BNC jack in my random parts bin, know I had one somewhere… or change to a 3.5mm connector failing that.

See 2 posts above for the exact what the additional circuitry does. It’s not really a necessary addition but it still does help . Making little electronics/software projects like this is fun for me and the engineer in me has a compulsive need to make things better.

Also whatever blend machine you use would very likely have something similar, if its something like DC strength 1-100 then using 50 will probably always give you 500ma no matter which person it’s used on (though they probably used some sort of digital potentiometer/DAC that outputs 12v by itself and doesn’t need the additional opamp I had to use since my 5v DAC was just what I had lying around).

#22

Ah I see, yeah I’m likely worrying too much, maybe a tad on the germophobic side lol

#23

Good, glad you got it. Yes, the blend machines have all the “stuff” you are talking about (I don’t pretend to know about electronics) … we just called it “constant current”: set the DC and the voltage keeps the current at a constant level.

However, I have to say that something WAS lost with the newer circuits … but, that’s a long (and forgotten) story. However, without “constant current” we could tell when the client was experiencing more pain and could instantly make adjustments. They thought we were reading their minds … but we were just watching the meter! (A slight drop and we could up the HF and go faster; a sudden spike in the DC … we knew it was “killing” them … gripping the sponge or sweating …

#24

Liking the new cable! No longer have a giant piece of plastic blocking some viewing angles and screw cap removes my pain of having to use pliers to replace the probes. I left the air tube on so it can’t be mixed up with my foot pedal cable and it also just kinda looks nicer with it. Most importantly my machines like 50% less of an eyesore with it instead of my makeshift cord. Much appreciated!

When I was still using the analog potentiometer I noticed that the current could rise about 50-100ua over the course of a hair treatment. Could have just been me slightly moving the needle around while tilting my head to get a good look at the multi-meter tho.

But if 50-100ua is a normal rise without constant current then maybe with the older circuits the slight current ramp up allowed you to squeeze in more DC power without the client noticing additional pain.

I’m no expert either, but if electrical engineers get to pretend they can write software I feel it’s fair I can pretend to know how to make circuits ;).

#25

With the last addition think I might be out of ideas for things to add to my galvanic circuit that would actually be helpful. Could add a cataphoresis switch but think the general opinion I’ve seen for cataphoresis here is it’s helpfulness is dubious at best. There’s also some sort of pulsing DC thing but that sounds like it’s just to reduce pain for sensitive people and just makes treatment longer.

Also could add auto trigger on insert, not exactly helpful for slow paced DC though. Not sure how the pro machines implement it but way I’m thinking is to send out a very small test voltage at all times to determine if the circuit is complete and fire after a 1s delay. Or do they use something like a pressure or distance sensor? I remember seeing people mentioning that sometimes it triggers too early so it would make sense that they do it the simple test voltage way.

Then there’s multi needle galvanic, extremely likely would be too insane for DIY. I’m imagining me wrapped up in rat’s nest of cables yelling to my neighbors to help get me unstuck. And 16 probe holders is cost prohibitive.

A thermoylsis/blend circuit would be fun to make and opens up many extra things that can be added on. But would need to learn blend stuff. Might have to buy/rent a blend text book soon so I would know how to actually use it correctly.

#26

Actually next I’m going to change it to be controlled by my android phone over an audio cable with a mic channel, android->arduino is the audio part and arduino->android is the mic part. Android will just sends what power level it wants and Arduino will still control the constant current circuit and will send the Android the active timer, kill count and the person’s resistance values.

For other crazy people looking to do something like this project this will lower the cost by $10 since the touchscreen is no longer needed.

Could also use a bluetooth chip to make it slightly cleaner. Bluetooth chips can be had for $2 but only come in 30+ pin SMT packaging which is a little ridiculous to solder by hand so would likely have to use an already soldered bluetooth module which you can find for $6 at the cheapest.

#27

So earlier in the week I wrote my own dinky little audio cable to android modem code just using tones and could only squeeze out 48 b/s which is insufficient for all the data I want to send. So I need to switch to an actual library that has already been written for this called SoftModem that can get up to 2450 b/s, but it doesn’t work with the arduino I have since it’s timers and interrupt pins are different so I need to modify it.

I’ve also been bumping my current up slowly, up to 850uA now and havn’t noticed any additional pinkness/irritation/swelling. Planning on getting to the 1.5mA-2mA range which seems to be the max any blend or ‘fast’ single needle galvanic operator uses. The way I made my circuit it can only go up to 1ma with worst case 10k ohm body resistance which I thought would be more than enough but I’m suddenly feeling the want/need for more so going to switch the circuit to use 24v by just using the -12v rail as gnd and give it a max 2ma at 10k ohms and also need a better fuse setup since 24v at 1k ohm is 24ma which can be deadly. [my current fuse is a 200ma with a 13v zener diode that will clamp down and blow the fuse just in case the power supply gives > ~13.5v, max current at 12v is manageable so high fuse value was fine but with 24v it is not]

#28

Can’t say I understand at all what you are doing. I do know that 1.5mA - 2.0mA is generally too much for single needle DC.

There is nothing more simple than a DC circuit and a few electrologists still use a battery (yes, really), like they did 100 years ago.

Are you using battery power … or “plugged into the wall?” I don’t “get” what you’re doing, but it’s somewhat entertaining. Don’t “blow yourself up” kiddo!

#29

Saw the max current for single needle in a couple places, heres one for 1.5ma: http://www.hairtell.com/forum/ubbthreads.php/topics/102033/Re:Failed_LHR-_Looking_for_e.html#Post102033

Since blend goes up to 2ma that sounds like the max anyone considers safe enough for a person for any method (ignoring the person’s skin’s safety)

Plugged into the wall!! 9Vs are expensive and drop well below 9V long before they’re ‘dead’ and I didn’t want to shell out $20 for rechargeables.

I’m using a linear regulated +/-12v power supply that uses an unregulated 500ma wall wart plugged into a surge protector. The power supply was taken from a modular synthesizer that I built most of myself, I sold off most of it a while ago but still had this power supply left which luckily was one of the few modules I didn’t solder together myself (though I have built my own wall power supply too). The PSU is something people trust with thousands of dollars worth of audio/synth equipment so I somewhat trust it with supplying current into my face.

The actual electro circuit has a few “safety” mechanisms. First there’s the opamp that acts kinda like a voltage limiter since it’s input signal comes from the arduino/DAC which can only ever give 5v and the opamp multiples it x2 currently so it will only output 10v max even if the main supply voltage bizarrely increases. Then the DAC output voltage is controlled by a microcontroller which measures resistance/current and adjusts the DAC output voltage as needed and also if the resistance is outlandishly high it just shuts the signal off. Lastley there’s the fuse+volt limiting zener diode, reverse polarity protect diode and a 1k resistor right after the cathode/needle mostly to protect the sensitive components like the microcontroller from shorts such as the probe and anode touching directly.

Also I use a circuit simulator to double check things and a multimeter when I make the change. If/when I switch to 24v probably going to add redundant resistance/current detectors since my arduino has analog inputs to spare.

So don’t worry! Chances of blowing myself up are likely less than me dying in a car crash tomorrow (though I turned 25 a bit ago and I believe car insurance companies say that means I magically became a better driver)

#30

Android phone hooked up to it over bluetooth:

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github project page here

Onto thermo/blend I guess! So need to cobble together some sort of 13.56 MHz oscillator circuit and amplify and control V pk-pk from the 30V to 70V range. Unlike Martha’s design I have a microcontroller at my disposal which will generate the timings. Also will need to modify the DC circuit a bit to prevent RF interference from the thermo circuit.

#31

Started chronicling my DIY adventures on my blog so I’m somewhat shamelessly plugging it here, first post can be found here.

Also a post about the simple usb webcam macro mod I bumped into is here. (Though I already posted it in one of Seana’s threads)

Was going to do an update on the webcam macro mod but for the last few days I have been completely blanking on it and shaving my entire my beard in the morning, oops. And I’m still planning on building and posting the thermolysis DIY machine sometime soon.

Also boycott Tinder!

(No, there is no such thing as shame when pageviews are involved)

#32

Oh boy. I recognize some of the motivations now :slight_smile:

Practise Practise Practise.

Hairtell will be needed for a while yet!

#33

Havn’t posted in a while here! But I’ve secured the funding to continue work on these shenanigans, though I’m more lacking in time now. Upgraded the old ugly makeshift case today to an actual case!

Boring longer blog article about it here: https://mabboud.net/hair-o-matics-new-case/

and pretty pictures:

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#34

Your DIY build is looking pretty spiffy!
Some questions for you:

Anything at all remain of the original one touch?
Since you seem to be playing with some combined thermolysis and galvanic, at what frequency is your oscillator alternating the radio frequency current?Some machines use 13.56 mhz, others 27 mhz.

Any plans to put in preset routines? Thousands of a second pulses?

Surely you have more invested in this project by now than you would have had you just bought a used machine off of ebay?

how about success rate in epilation? You are correct it has been a while, in this much time you could have made some real progress in hair removal, or is tinkering eating up most of your epilation time?

Good luck with this project, and if you ever decide to spend more time on hair removal than on tinkering with your electronics, hit me up for tips.

Seana

#35

One touch is way way long gone. I think I might still have the makeshift probe holder lying around as a backup but that’s it.

Haven’t actually added thermo yet! sorry if that wasn’t clear.

Have a little circuit diagram in lt spice drawn up for it and a mouser cart full of parts for it I’m going to order soon (mouser is an electrical component store)

It’s going to be 13.56 mhz couldn’t find any solid evidence of 27 mhz being superior.

I’m trying to remember what timings the Arduino pulse generator I’m going to make with one of its outputs is capable of doing but it’s been a minute since I researched that, I think it can do down to 1000ths of a second at least.

Will have to redo the DC circuit as it needs to be re-enforced against RF interference from the thermo circuit or the microcontroller and the nifty stuff it does will be messed with.

I might actually buy a used machine so I have one that I know works to learn/compare with. My blog addresses this though, for the fun of it! Though I’m still currently only in $60 or $70 on this so not price wise, timewise probably, but it’s fun.

I’ve been going with the spread out vs area clearing method which makes it hard to tell but I did clear out a small patch on my front chin and one on my sideburn for this purpose and they both haven’t had any regrowth and it’s been 5 or 6 months.

Area under my chin where I first started practising has of course had some regrowth. The oopsies I made on the bottom of my chin while learning have all disappeared though, kinda hard to scar yourself with DC I think.

Currently my hair kill counter says 3050 but there was around 1500 to 2000 on it before it got reset when I changed things. So 5000ish out of worst case 40k hairs(think 40k is worst case?), so I’m getting there lol.

Current job requires my face to be pretty at all times which is the biggest impediment to my progress on this. Planning on taking a week off sometime and just binging out on hair killing.

#36

Well, I’m still going to recommend you buy a used blend machine to work with. This is all well and good as a fun experiment, but a face, no you will treat more than 40000 hairs I’m sorry to say.You’ll want and appreciate the increased epilation time of blend . I’d still recommend investing a few hundred into a good quality used blend epilator. One where the timings and circuitry have already been figured out and engineered for you ( by experts). Havingdone my own face, strait thermolysis is too risky, improperly regulated electrolysis shares this risk. Blend on a professional machine can be done without the same level of risk, and pure galvanic , is just too slow in my opinion to ge tthe job done on as many hairs as you will face in a beard removal. While I appreciate the DIY aspect, I think you may have taken it to it’s conclusion. Time to move on and kill some hair with a little better efficiency.

Seana

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