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This project is currently being updated. Feel free to get your comments and suggestions in so that the feedback can be used in my next build.

There is a problem with the circuit. Please see the comment from Zanderist below. I have updated the schematic in the next step.

So when I wanted to quit smoking I tried an electronic cigarette. They were expensive and didn't produce enough vapor for me. I figured hey it can't be that hard and decided to look into making my own.

Approximate cost not counting batteries is about $12

I took my existing electronic cigarette and hooked it up to a voltmeter and started making notes. I found other electronic cigarette models that had variable voltages so I decided to search through several forums out there to see what range of voltages were being used.

I found that most operate off 5-8vdc with wattage being a little higher than just from the battery alone so battery voltage needs to be higher than what is being used and the amp hours need to be high.

I found that most electronic cigarette mods were using IMR 14500 3.5v Lithium Ion Batteries

Needing to control the voltage I looked at several voltage regulators and came up with the LM317 because it supports the volt range I'm working with. I also wanted to leave room for creating a desktop model.

Nicotine use in the US requires you to be 18 years of age or older but then again this project isn't about nicotine and I didn't use any when I really began to quit smoking.

Feel free to ask questions and/or make suggestions.

Step 1: Application Schematics & Math

Use the first schematic in this step. This update is from working with Zanderist. This was originally designed for the LM317 voltage regulator but after suggestions from Zanderist the design is now using LM338t. Other schematics are from my first design and manufacturer specs.


As far as the math goes I've done it for you so don't worry too much. I calculated the values based upon 7.5vdc but the intended use is around 6.5 to 7vdc. I left in the overhead because as the batteries get drained you can crank it up.

<p>This thing is dope</p>
<p>Awesome!</p>
<p>Don't use the LM317 IC, its rated at 1.5 amps which is too low for this application.</p><p>It would be better with the LM338t, if keeping to this design layout. </p><p>However if choosing to use the LM317t you will need to use an additional power transistor (which you can also buy at radio shack) to increase the current output.</p><p>A quick google images yeilds the following results:</p><p>https://www.google.com/search?q=lm317t+increase+current&amp;espv=210&amp;es_sm=122&amp;tbm=isch&amp;imgil=853-qQRm6avh-M%253A%253Bhttps%253A%252F%252Fencrypted-tbn2.gstatic.com%252Fimages%253Fq%253Dtbn%253AANd9GcQpeG2hW_Yimcj4GH0PmIpz30fgfkOMvMd-DGCpgk4ojh9p1DXRUQ%253B400%253B218%253BiEw08L4XO6s4AM%253Bhttp%25253A%25252F%25252Fwww.reuk.co.uk%25252FLM317-High-Current-Voltage-Regulator.htm&amp;source=iu&amp;usg=__0_BJ-c6grb9Z8IisngXh64-Crrg%3D&amp;sa=X&amp;ei=pKLyUvDQL-fNsQT2-4CgDw&amp;ved=0CD0Q9QEwAg&amp;biw=1240&amp;bih=642#facrc=_&amp;imgrc=853-qQRm6avh-M%253A%3BiEw08L4XO6s4AM%3Bhttp%253A%252F%252Fwww.reuk.co.uk%252FOtherImages%252Flm317t-pnp-pass-transistor-voltage-regulator.jpg%3Bhttp%253A%252F%252Fwww.reuk.co.uk%252FLM317-High-Current-Voltage-Regulator.htm%3B400%3B218</p>
<p>Wow I stand corrected! I completely over looked this when I designed it. Knowing this now I can't believe it still works after a year of heavy use. I will have to build a version 3 with the LM338t. I have already been kicking around the idea of building a variable wattage version using a micro-controller.</p><p>7.5 vdc and 2 ohms = 3.75 amps</p><p>7.5 vdc and 1.5 ohm = 5 amps</p><p>Thanks for the feedback.</p>
<p>From the LM317 Datasheet</p><p>Electrical Characteristics:</p><p>VI-VO = 5 V, IO = 0.5 A, </p><p> 0&deg;C &le; TJ &le; +125&deg;C,</p><p> IMAX = 1.5 A,</p><p> PDMAX = 20 W, unless otherwise specified.</p><p>IO(MAX): (Maximum Output Current) :: TA = 25&deg;C</p><p>VI - VO &le; 15 V, PD &le; PMAX MIN: 1.5A TYP: 2.2A</p><p>VI - VO &le; 40 V, PD &le; PMAX MIN: 1.5A TYP: 0.3A</p><p>Further More:</p><p>Description:</p><p>This monolithic integrated circuit is an adjustable 3-terminal</p><p>positive-voltage regulator designed to supply more</p><p>than 1.5 A of load current with an output voltage adjustable</p><p>over a 1.2 V to 37 V range. It employs internal current</p><p>limiting, thermal shutdown, and safe area</p><p>compensation.</p><p>Focus on line: &quot;designed to supply more than 1.5 A of load current&quot;</p><p>So, if you can keep the LM317 at 25&deg;C (77&deg;F)</p><p>You can supply at least 2.2A (maybe more) :: it really depens on the temperature coeffiecent</p><p>and the output current is internally limited (again accouring to the datasheet)</p><p>-- this is why it has been working for you</p>
<p>The texas instruments datasheet says the current range is:<br>MIN: 1.5A TYP: 2.2A MAX: 3.4A<br>@7.5 vdc<br>You could use: a 2 ohm - 5 ohm coil<br>7.5/1.5A = 5 ohms<br>7.5/2.2A = ~3.41 ohms<br>7.5/3.4A = ~2.1 ohms<br>7.5/3.8A = ~2 ohms</p>
You probably would only need a mircocontroller if you wanted a display. unless your going to try a PWM style of variable wattage.<br><br>I've been trying to reverse engineer the whole variable wattage thing to sorta debunk if its just a marketing gimmick. <br><br>Something variable wattage could be done pretty simply I suppose with something called a trans-conductance amplifier .
<p>Well it's not entirely a gimmick. The wattage is what drives the heat so it gives you a more consistant vape. This is done by calculating the ohm rating of the carto quickly and then delivering the amount of voltage needed to create the amount of wattage desired. </p><p>Now I'm curious about doing variable wattage without a micro-controller. I'll take a look and see what I can find too then post my findings here.</p>
<p>I've already blazed a trail for you to follow into then, you've cleared up the vary wattage thing then.</p><p>What you have in the following image is a noninverting op amp driving a transistor in an emitter bias configuration. Nice thing about this is it takes a very small voltage to drive the opamp. The dc voltage source you see going into the op amp could be sub'd for a potentiometer set up to be a voltage divier. What it comes down to is the gain you choose at the op amp.</p>
Oh ok cool! I think I may already have the parts. I'll look tomorrow and see.
<p>Just for everyone to see I have made one of my own inspired off of Redbeard.</p><p>I found a DIY tutorial that showed and explained the idea on how to make printed circuit boards.</p><p>In addition I used re purposed laptop batteries found from a dead laptop to drive the Ecig.</p>
<p>That looks awesome! Great idea using the laptop battery.</p>
<p>Thanks for this, it's the best help I have found so far. My daughter is working in Arduino and wants to make her own version of the Tempesco-- it's a clear box that shows you what the weather outside by making it cloudy or rainy or other inside a closed, clear box. So, I was thinking that getting the atomizer working that you guys use in your vape things would be a good way to go. Since we don't vape, can you tell me-- are these atomizer parts supposed to be disposable?</p>
Yes but they are fairly cheap to get especially for what you're doing. I've seen people make fog machines with them and its funny because that's where the technology came from in the first place.
<p>Hi MrRedBeard, really interesting project. I would like to create an arduino-controlled ecigarette voporizer, your project seems to come very close. What I am currently not quite understanding, probably due to the lack of knowledge about ecigarettes, is how the liquid is going through the tin and is then later somehow vaporized. Did I miss the part for that? Any tips/hints/links would really be appreciated. </p><p>thx for sharing!</p>
Hi. I want to learn how to make a variable wattage device which goes up to at least 100 watts, maybe 150 watt, with a display and if possible temperature control like the latest box mods you can buy. If i can build these devices here in the United States and sell them at a competitive cost then i guarantee anyone doing this will get rich real quick. <br>Im not an electronic genius but im good at selling. Anyone want to help me figure out how to build these? Electronics tech needed
<p>So a box that goes to 100 - 150 watts and can display possible temp. They are making these currently. It uses nickle wire and the controller reads back the temp. There is something about nickle that makes this possible. Just making a wild guess I imagine they measure the resistance and wattage before then use those values with operational resistance. I could design and build a prototype.</p>
Oh email me at buddy4341@gmail.com if anyone can help build a box mod like this..?
Oh email me at buddy4341@gmail.com if anyone can help build a box mod like this..?
Oh email me at buddy4341@gmail.com if anyone can help build a box mod like this..?
Oh email me at buddy4341@gmail.com if anyone can help build a box mod like this..?
Hi. I want to learn how to make a variable wattage device which goes up to at least 100 watts, maybe 150 watt, with a display and if possible temperature control like the latest box mods you can buy. If i can build these devices here in the United States and sell them at a competitive cost then i guarantee anyone doing this will get rich real quick. <br>Im not an electronic genius but im good at selling. Anyone want to help me figure out how to build these? Electronics tech needed
Hi. I want to learn how to make a variable wattage device which goes up to at least 100 watts, maybe 150 watt, with a display and if possible temperature control like the latest box mods you can buy. If i can build these devices here in the United States and sell them at a competitive cost then i guarantee anyone doing this will get rich real quick. <br>Im not an electronic genius but im good at selling. Anyone want to help me figure out how to build these? Electronics tech needed.
i love this
Please contact me ASAP <br><br>i have a business proposal <br><br>Mustafa.may@hotmail.co.uk
<p>Thank you for including a schematic, you wouldn't believe how many guides dont include one.</p>
<p>I see another problem here, the lm317 is not heatsinked, so it gets real hot and dies very quick.For this application i would use a step down switched supply.z.B. LM2596. It wastes much less power.</p>
<p>i am trying to use the lm338t adj nd on my dmm it reads that i am getting volts but when i put it on my tank it wont fire please help</p>
<p>If your getting voltage out on the connector that goes to your tank then it should be good to go. Check the resistance on your carto/coil. You should get 1-3 ohms. In your dm you said you were getting 7.5vdc? That may have popped the heating element (some don't like going that high especially if they're used). If that is the case adjust the voltage down between 3-5 vdc.</p>
<p>I also want to add if you are going to use PWM, you may need to introduce some RF shielding. The FCC may end up giving you a fine, haha.</p>
<p>Haha but that's a cool thought shaping the waveform to fit a desired freq. Thanks Zanderist now this will consume my thoughts.</p>
Hey if I didn't want to use the potentiometer what could I use? can you take some up close pics of the PC board sorry I'm still learning how to read circuits the only place I get parts are at radioshack and what v are the caps?
The capacitor in the list is rated for 250vdc. I built one using all radioshack parts, I will get you more info on that shortly. <br> <br>As far as the variable resistor you can leave it out and have the voltage at around 7.5vdc but understand some e-liquids may not taste good.
Thanks for the info but it seems I'm missing something. How are you getting VIN 28v from 2 3.4v Lithium batteries?
No I am getting ~6.8vdc from the 2 3.4vdc lithium batteries. The 28v is the upper tolerance of the LM317 voltage regulator.
that is some wild customization you got there!
Haha Thanks
I am not a smoker but where do you put the magic liquid and how does it vaporize it?
It goes inside the cartomizer or atomizer which has a heating element. I used a tank on mine which fed the cartomizer through a pin size hole which kept the heating element cooler during longer operation and fed it consistently which meant I didn't have to always carry the liquid with me.

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