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Engineer turns disposable vape pen into a working web server (interestingengineering.com)
submitted 5 months ago by to c/technology@lemmy.world
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[–] 56 points 5 months ago* (18 children)

Because an existing SoC at scale is cheaper than a custom ASIC.

You see this all the time, custom keyboard running ARM+Linux, SmartNICs using RISC-V cores/FPGAs instead of ASIC accelerators. Even Microsoft refuses to commit to ASICs for network processing in their DCs and use FPGAs instead.

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  • [–] 35 points 5 months ago (17 children)

    A vape is a battery connected to a button connected to a heating coil. You might want a single transistor. You don't need a software platform.

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  • [–] 30 points 5 months ago (2 children)

    Sure, if you weren't competing with every other vape out there that has things like variable voltage settings (at least 3), a pre-heat feature, the ability to turn on/off with 5 presses, or to turn off automatically after 5-10 minutes without use, a low battery indicator, a charging indicator, a broken coil indicator...

    Hmm, seems like you need a lot more than a battery, heating coil, button, and single transistor.

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  • [–] 6 points 5 months ago

    With the major caveat that dispos dont offer more than 2 of those features at best. Almost all those features you specify are on reusable devices. There are going to be some that do have those additional features, but at a price point that makes them nearly as or more costly than a reusable device.

    The only IC you need for a disposable really, is a BMS, and a temp sensor (technically a timer so it also doesnt over draw, but timer ICs are built into everything) so it doesn't willfully light itself on fire in unusual circumstances.

    All that to say: there is effectively 0 difference between most disposables released today and reusables, with the sole exception that you cant refill or recharge them. There should be no device with a battery deliberately intended to be thrown away, for anything, save for medical uses.

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  • [–] 3 points 5 months ago

    You’re sooooo right, check my response to that guy. I was into vaping years ago and loved mechanical vaoes, which were legit just a battery, heating coil mounted to a platform, button, and conductive tube. Super simple devices, so easy!

    Except they’re INSANELY DANGEROUS! I loved them but I’ve had friends treat them carelessly and they WILL start on fire or even explode if not vented. You need a thorough understanding of Ohm’s law, batteries’ amperage limits, how to rewrap batteries with nicks in the wrap, and to never leave them unattended even with manual locking rings.

    The person you replied to mentions adding a transistor which would do nothing. Add some more bits and just like you said, you’re competing with fully functional vapes with all those features and they’re cheap as hell. The chips cost nearly nothing, so that’s the route they go. Those vapes aren’t impervious to blowing up, but they’re much safer than simple mechanical vapes.

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  • [–] 28 points 5 months ago

    There is also a battery management system as well.

    M0 processors are dirt cheap, especially in bulk.

    They probably have a BMS library that takes a few Kb of flash.

    The time it would take to make the design cost effective wouldn't be worth it.

    Slap a less than a dollar mcu and be done with it.

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  • [–] 9 points 5 months ago (7 children)

    Disclaimer: I don't smoke anything, so I don't know any details.

    Wouldn't a button connected to a heating coil be a fire hazard? Is there no automatic shut-off based on temperature? If you add enough safety features, it might end up costing about the same as an embedded SoC.

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  • [–] 7 points 5 months ago (5 children)

    All it would need is a thermal fuse/cutoff, like those in portable heating appliances (air fryers, grills etc.). I wonder what's needed to include a 10 second on & 30 seconds disabled timer, maybe it's cheaper

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  • [–] 6 points 5 months ago (2 children)

    I wonder what’s needed to include a 10 second on & 30 seconds disabled timer, maybe it’s cheaper

    555 timer and a transistor or two, I think?

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  • [–] 2 points 5 months ago* (1 child)

    Digipart is showing me price for PY32F002B with a minimum purchase of 5000 as less that $0.10 (not the factory price, just the cheapest store).

    The price for the cheapest NE555 (random manufacturer implementation of a 555) variant in Digipart is $0.13

    (Granted, you also need at least a crystal and 2 caps, plus 1 power filtering cap per power line for the microcontroller, but those are all cheap)

    It's ridiculous how modern microcontrollers are so stupidly cheap that even though they can run a lot more digital logic (in the form of software running in them) they almost always beat using older and much simpler digital parts even for something as simple as this.

    Even microprocessors are getting stupidly cheap: somebody recently pointed me out the Allwinner F1C100s, which is about the smallest microprocessor that can run Linux, and it costs $2 in bulk to the point that some embedded engineer has made a business card with one running Linux which he just gives away.

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  • [–] 0 points 5 months ago

    You’re 100% correct. I have mechanical vapes—no safety cutoff, just an 18650 in a conductive tube with wire coils attached to posts. They’re amazing, and they’re extremely dangerous. Turning one into a protected vape with basic features like wattage adjustment? Way cheaper and easier to go SoC!

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  • [–] 9 points 5 months ago

    I used to be into vaping and a big mechanical vape fan. I still have all of my old mech vapes! Those were what you’re thinking of—a button, a conducive body, and a coil or two mounted to a post. You pop an 18650 in, no transistor or resistors needed. You adjust your wattage by changing the way you wrap your coils, and your wire gauge. Generally I’d like to run around .2 ohms, which pushes about 18-20 amps out of the 18650s.

    These are NOT devices you want in the hands of regular people lawl. I’ve had friends in years past love how my setup was and get similar vapes for themselves. I’ve seen a burned-down backpack (RIP, all of his adderall XR), a table almost catch fire, and burnt carpet. No explosions because I told people “don’t get one of these, but if you’re not going to listen to me, for the love of glob make sure it’s vented.”

    Anyway, yeah no way anyone should have these except electronics enthusiasts. Even with locking rings, they can just start firing if the person using it isn’t super careful. Nice batteries rated for 30a pulse are 2USD more than the garbage batteries that love to vent or explode.

    You add in a transistor, that’s not gonna do anything. You add in a couple more things for protection and your cost is higher than it would have been by getting one of the chips in OP’s article, and you don’t have a nice interface for adjusting wattage and checking battery level and charging via USB and all that fun shit.

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  • [–] 3 points 5 months ago (2 children)

    i disagree with the single transistor. overcharge prevention requires something more (i am not a batteriologist don't ask me what. i'd do it with a tesla coil because that'd look cooler)

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  • [–] 2 points 5 months ago (1 child)

    I was assuming it was disposable (as so many are) and therefore no charging circuit.

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  • [–] 1 point 5 months ago*

    Huh. The disposables I am occasionally "forced" to get (put it in a 510 thread gramma) have charging ports. I usually have to charge once or twice to get through the full gram.

    That being said, the good local dispo just rebranded and gave me a bunch of 510 batteries with the old name on them. These batteries are fantastic and look about the same size as the server in the article

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  • [–] 2 points 5 months ago

    There is a little more to it, pressing the button 5 times turns it on and off. Three times often lets one cycle through power settings. But yeah, anything more than a very minimal programming is frankly suspicious.

    It could be a lot is used to get the charge right idk.

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