Hackaday Prize Entry: An E-Juice Robot

E-cigarettes are increasingly popular, with weird hipster head shops popping up in towns around the globe. While you can buy this e-juice at gas stations and just about anywhere else analog cigarettes are sold, there are inevitably people who want to mix their own propylene glycol, glycerin, water, and nicotine. For them, [conklinnick] is building The End Of An Evil Industry, an e-juice printer that automates the entire process.

This ‘e-juice printer’ is designed to mix the basic ingredients of the consumables for e-cigarettes. These ingredients are propylene glycol and/or glycerin, water, flavorings, and nicotine. [conklinnick]’s project is using different ‘stations’ and a camera slider to dispense these ingredients into a small vial. It’s effectively a barbot dispensing ingredients for silly putty instead of alcohol.

It’s a great project, and although it’s not for everybody – nor should it be for everybody – it’s a great application of homebrew tech we already have for new uses.


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49 thoughts on “Hackaday Prize Entry: An E-Juice Robot

  1. While the machine may not be bannable, I am pretty sure when they get to banning, it will be the ingredients that are banned. Since this project relies on the availability of those ingredients, this is hardly “unbannable.”

    1. PG and VG are in *everything*. Want a sausage mcmuffin at Mcdonalds? You’re getting propylene glycol. Nicotine? If there are people extracting reasonably pure THC in a college dorm kitchen (there are. or rather, there were), you can get pure nicotine out of a plant at home.

      The only truly idiotic thing about this would be adding nicotine by itself. There’s enough nicotine in a single pack of cigs to kill a rather large man; it’s just that burning it and inhaling it cuts the bio-availability a lot. Getting a PG/VG/nic mix would completely eliminate that issue.

      1. Most definitely true. One interesting tidbit from our family:

        My mom’s dad’s family grew up in Kentucky, and grew tobacco as their crop. When the rules came in effect from the cigarette companies, they could only use 1 pesticide on their crop: nicotine. Now, why would they spray nicotine on their crops? Because these things take over if you don’t: http://entnemdept.ufl.edu/creatures/field/hornworm.htm

        My family was poor, so getting nicotine was somewhat hard. Well, it’s a lot cheaper if you can make it. So what my granddad did was have a 5 gallon glass jar half full of water, and he (and others) put their butts in the jar. After about 6 months, it stank to hell and back… but they siphoned and filtered the water. Lo and behold, they had a high concentration of nicotine water for free.

        It was also one of the only times you’d catch him wearing gloves. A bit landed on his skin the first time, and he was bedridden for a few days. Turns out, nicotine can subdermally enter the blood stream.

        1. Interesting, I had no idea that tobacco worms (horn worms) could be prevented by spraying nicotine. While I was going up in KY, we used to trap those things in jars and keep them as short-term pets all the time. They look scary, but aren’t harmful to humans at all.

          Nicotine can most definitely enter the blood stream subdermally. I never had a reason to look it up before now, but I remember being told stories from my father (also in KY) about getting sick while picking tobacco by hand. The CDC has a decent page on Green Tobacco Sickness: http://www.cdc.gov/niosh/topics/greentobaccosickness/default.html

          1. Yes! Horn worms are scary looking! I remember them from my childhood. And nicotine patches deliver nicotine through the skin, so of course it can be absorbed dermally. .

    2. Yes, they could ban nicotine extracts. But:

      Nicotine per cigarette: ~12-18mg
      Nicotine delivered to smoker per cigarette: ~1mg (the rest is burned, or not inhaled/absorbed)
      Efficiency of nicotine delivery via vaping: ~50% (though highly debatable, insufficient formal studies)
      Efficiency of extracting nicotine from cigarettes at home: >75%

      Lots of uncertainty in these stats, but it’s still clear that so as long as there are cigarettes, vapers can still get their nicotine at a deep discount. (At least those who are also hackers.)

      PG, VG, and food-grade flavorings are indeed everywhere, will never be banned, and can be obtained easily with no need to extract them from Sausage McMuffins.

      1. Hell yes. No matter what ban or laws get passed, people will always get what they want. A 5 pound bag of shredded tobacco (tax class L) is way cheaper than cigarettes, or you can buy a 200 pound bail of cured tobacco from a friendly southern tobacco farmer. You could also grow your own if your climate or hydroponic setup allows.

  2. I buy unflavored premix pretty cheap. I’d rather not risk messing around with pure nicotine. That stuff is quite dangerous if you’re not careful.

    $30 or so for a 235ml bottle of 50/50 pg/vg 24mg unflavored liquid and $2-3 for a 10ml bottle of flavoring that’ll last a looooong time, even at heavy usage.

    1. Let me put your concerns into context.

      There’s some dispute over the LD50 for nicotine but it’s definitely less than a gram, and historical documents indicate that it’s less than a tenth of a gram.

      Nicotine is readily absorbed through the skin, and you can die by spilling it on your hand. The link below tells of a girl who spilled 7.5cc on her overalls, immediately removed and washed them, returned to work, and collapsed 20 minutes later.


      The symptoms tend to mimic those of intoxication, so others will think you’re drunk and won’t know to call the ambulance.

      It’s called “one of the most deadly poisons known”.

      (I’m not a fan of “Fireman Bill” posts which point out trivial dangers, but this danger isn’t trivial.)

      1. it’s deadly enough that it was one of the few toxic substances featured in the old usenet classic Uncle Fester’s that was and still is easy to get your hand on. While I doubt the method described in UF would be even near 90% efficient, the LD50 is low enough that a spiked drink would be fatal. Probably taste like shit, but the buccal absorption would be high enough to still make a person very very ill.

        And I wouldn’t call “Hey, this is dangerous, know what you are doing” comments Fireman Bill trolls. Just like with the infamous SCUBA tank posts. It’s a hack, we’re all adults here, as long as everyone knows the risks involved. If bringing up the risks is what comments are for, so be it.

  3. Why the complication of a linear translation, when you could very, very easily use syringes with a Luer connection, and simply join the tubing from all syringes close to the bottle? Much simpler, less code, same result*. If no cross-contamination of the different flavours is acceptable, flush the mixer with whatever is the cheapest ingredient. Choose the order of connections wisely.

    *Because all ingredients will end up in a mixture, I’ll just assume that they are chemically compatible

          1. As someone who vapes, I don’t like most other people that vape also.

            I can’t speak to Marvin’s grievances against them, but in my experience most people that vape seem to be very unaware of the people around them. A lot of them will take the “second hand vapor wont cause cancer” thing too far and blow the vape right into other peoples faces.

            Combine this with the fact that a lot of vaping rigs can create a ton more vape than a cigarette creates smoke and you have a perfect recipe for some annoying people.

          2. I’m guessing it’s because of the “hipster” aspect. While the hipsters are probably a very small minority, they’re highly visible. Just a few weeks ago I encountered an attention-needy one in Walmart, sneaking up behind people then blowing large clouds of what must have been 100% VG.

    1. Why?

      Do you also yell at children to stay off your lawn? Are you so full of animosity, disregard, and “hate” for other citizens that you can be so condemnatory over something that does not hurt you?

      Are you pro war and hate hippies? Maybe vote for fascist racist right wingers?

  4. As long as certain loopholes still exist in tobacco taxation, you can roll a carton of cigs in the US for about $12. Already cheaper than the equivalent amount of store-bought juice.

    For those who favor juice, and are thrifty enough to want to mix their own, I *seriously* doubt they would invest the money required for an automated mixing machine. Especially when the labor saved is minimal, and can be reduced to any arbitrary degree simply by mixing larger batches.

    1. This device hopefully wont end up on kickstarter, but you are right – unless its ‘for fun’ – obviously building such a machine would be fun for many people here.

      If they try to kickstarter it, it will likely fail for the reasons you mention.

  5. The project title “The End Of an Evil Industry” is just ridiculous. Perhaps this person is not a smoker? I know many people that have tried vaping (including myself), and go back to cigarettes within 2 weeks. Women seem to have an easier time quitting, and I can reduce my smoking by vaping, but tobacco smoke is far more complex chemically than just nicotine.

    1. I’ve wondered if there’s some herb or substance that could be added to e-juice to make it more complex and fulfilling. Preferably something far less toxic and physiologically addictive than nicotine, and excluding THC for multiple reasons. But still mildly pleasant, and most importantly something you would not get from a *real* cigarette; so that one would tend to reach for the e-cig more.

      Any ideas? I’m not really familiar with what’s out there, and might be a candidate. Damiana perhaps, but as my state of Louisiana has decided to make it and a slew of other common medicinal herbs illegal, it puts a damper on casual experimentation.

      1. I think maybe the flavorings fill this role – also, i am not involved in this passtime, but I think the more powerful vaporizers (as opposed to disposable ecigs) allow for huge satisfying vapor-hits.

      2. I personally use (and still use at work occasionally along with vaping) Cytisine, an extract available from several species of plants. It helps, but has a pretty short half life (about 1 hour), so if I don’t take it every hour I will start to feel the need to smoke. Perhaps modification of this drug to increase it’s half life would give a better result. The down side to it though, in higher doses, is a sleepy “over-relaxed” feeling, which is not good at work. I will try adding some Cytisine to a small amount of vaping liquid to see how that works.

        The anxiolytic properties of Damiana may be helpful for smoking cessation too. I will order some to experiment with.

        I have also tried Varenicline from my doctor, but had to stop after 10 days due to psychotic events.

        Tobacco smoke is pretty complex, and appears to contain a couple of chemicals that act as monoamine oxidase inhibitors, which can have an anti-depressant effect. Nicotine itself has a very short half life, so the other chemicals must play some role in the addiction, otherwise every smoker would be a chain smoker.
        Many years ago I tried putting tobacco in capsules and just swallowing them, and it worked great, but severe heartburn and the potential for a stomach ulcer made me stop.

        I would argue it’s not the nicotine that kills smokers, but the carbon monoxide and carcinogenic compounds produced when tobacco is burned. So, if you can eliminate those, you may extend your life a little.

        You can put just about anything in e-juice, so experimentation is possible.

          1. Now that I have thought about it more, I will try a reflux soxhlet extraction of tobacco with a 50/50 ethanol water mixture. Everclear 151 (legal in my state) cut with water to 50/50 will work to extract the polar and non-polar compounds. Then add the extract to the VG or PG, boil out the ethanol (or leave it in and get a buzz), and vape.

            This should provide the complex mixture of chemicals my brain wants, without the monoxide or decomposition compounds from burning the tobacco.

          2. Glad you two enjoyed the excerpt! It made the same impression on me when I was first introduced to it.

            The result of the tobacco extraction could potentially be very interesting. If you’re planning in doing this in the next few weeks, I’d like to hear what happens, and can check back periodically.

          3. @Mark Where did you get your soxhlet from, if you can share? I’ve wanted one for kitchen chemistry, but every glass supplier seems to have them priced really high.

          4. @Quin – I bought it about 20 years ago from Carolina Biological Supply company. Back then they had a good selection of glassware. You can try eBay. You might get lucky.

          5. @Mark the flea market approach has tempted me, but without knowing the lab that glassware was used in, who knows what sorts of organic or inorganic compounds went through it. I can think of many nasty things that could be refluxed that I would not want stuck to glass that I was going to use for food flavorants.

          6. @Quin- There is tons of glassware coming out out China these days at low-low discount prices. eBay has quite a few listing for complete sets with multiple flasks. Just remember to buy extra thimbles, and get some silicone high vacuum grease for the joints. They also have complete distillation setups pretty cheap too. What a time to be alive!
            And before you poo-poo China glassware- Remember- It’s glass no mater who makes it, and it will break in a split second if you drop it, so the less you pay for it the better.

          7. @Chris C – I have done two different extractions so far with excellent results. One with a Soxhlet extractor at 105 degrees C, and one by simply steeping (like making tea) the tobacco in the solvent (50/50 ethanol / water). The resulting extracts were dried in a desiccator over 4A molecular sieve to remove ethanol and water. The resulting concentrate was a translucent golden brown thick liquid. In both cases the smell of the concentrate was of fresh tobacco, but there was a distinct pungency to the material extracted by steeping, and a more roasted scent to the reflux extracted material.
            In both cases 0.1mL of the extract is added to 1mL of an unflavored VG / PG mix for testing. Both extracts were quite pleasing and satisfying.
            The extraction of 5 grams of tobacco yielded 0.35mL of extract with 10% water content.
            Extraction of tobacco is becoming a popular method for flavoring vaping liquids-

          8. @Mark – Thank you, for both your results and the supplemental links! I’ll be ordering PG and VG soon, and will try this soon after receipt.

    2. A few years ago I switched from smoking to vaping (God I hate that word…) with no problem. I had tried the gas station disposable e-cigs before that, but they were never satisfying enough. Noirwhal is right, the more powerful vaporizers are much more satisfying.

    3. You may need to try a better device that creates more vapour. The cheap dinky ecigs don’t satisfy the feeling for me, they are just like the gum or inhalers.

      What make ecigs work out (though not quit cigarettes completely, but cut back to a pack a week depending vs a pack a day) was getting a device that can produce a lot of vapour – so you feel it in your lungs.

      Try the kangertank sub ohm (and either a straight 18650 mod or one of the fancier variable voltage devices – check fasttech, straight mod shouldn’t cost you more than $20, the VV devices $30-60) if you just want something that works vs tinkering all the time.

      The VV devices are nice because you can change the wattage to get hotter vapour and have a bit more control.

      Depends on what your goals are really. I just wanted to save money and give my lungs a break because in canada packs are around $14 for premium cigarettes.

      1. Yeah, I was just about to try that. A buddy of mine has a BGO Subohm 40 Watt, and that thing kicks out piles of vapor compared to my little eGo-T. He was the only one of 6 people I know that used vaping to actually quit cigarettes, so maybe it has something to do with the amount of vapor.

  6. I’m not going to debate the lethality of nicotine, but I would recommend an improvement to the design shown. Linear actuators are going to give you issues. I would definitely investigate in peristaltic pumps instead. Any air in the system for a linear system is going to cause inconsistent pumps. With peristaltic pumps, you can implement very tightly controlled pumps, pull-back to prevent drippage, etc.

    Viewing this as strictly a materials pumping system, it has merit. The intended use however, I’ll leave that to the trolls.

    1. I would have gone with peristaltic pumps also. The only issue I would see with that would be when changing flavor. In that case you would just swap out the tubing in the flavor pump with a different one to avoid mixing flavors.

    2. Everyone knows nicotene is dangerous – these people just like to hear their keyboard clacking while that small adrenaline associated with ‘being right’ flows through their ego-driven veins.

      In the end this device is pointless except as a learning exercise.

  7. This thing looks pretty neat. It seems like its not that hard to squirt droppers into a tiny bottle. If you can just keep inserting empty bottles and letting it run, I can see an advantage. but, if you have to reset the fluid droppers every time, it just wouldn’t be worth it.

    The vapor mod scene is full of hackers. Tons of people are making their own E-cig mods. All you need is a few wires and a button. Although, many use chips to regulate wattage. Here’s one I hacked together with spare parts and Lego.


    The only problem is I burned out the button. I need to put a MOSFET in there.

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