Show HN: Hacking a $20 4G wireless hotspot into a texting device

(bkovac.github.io)

145 points | by bobili1234 6 hours ago ago

22 comments

  • walrus01 4 hours ago

    Based on the work the person has done, if they wanted to make something with an exceedingly long battery life, and the battery setup there already seems to be basically a 1S li ion, they could graft in a back side battery holder for two high quality 18650 cells in parallel. It would probably last weeks.

    • iamnothere 3 hours ago

      A 10000mAh pouch battery would take up less room and provide more battery life. They are almost as cheap as 18650s too.

      • walrus01 2 hours ago

        The neat thing about 18650s though is that you can put a battery door on it and make them swappable, if a person used a holder that can accommodate button top protected 18650 cells. The same cells can also be shared by a bunch of good quality flashlights and headlamps. I have several extremely useful headlamps from "sofirn" that take my choice of cell and have a built in USB-C charging port and charge circuitry protected behing a gasket and twist-open ip67 sealed cap. The pouch battery would be better as an integrated all in one product but also makes the thing a bit less modular.

        • iamnothere 2 hours ago

          There are advantages in some applications, it’s just not a one size fits all tool. Slim devices aren’t really a good fit for them. They make sense in round devices (like a flashlight) or larger devices where space isn’t as much of a concern.

          • DANmode an hour ago

            Thank you to both solder-nerds for contributing strongly to the thread, please don’t fight.

            • walrus01 an hour ago

              No fighting intended, I think it's interesting to see that there's many ways of doings things, and doing a sort of mental whiteboard exercise on what the benefits and drawbacks of different things are... Like, using cylindrical cells would let me share cells with my head lamp, swap cells, independently charge cells and keep spare charged cells ready.

              While using a pouch cell keeps the profile much more slim, portable, still has opportunities for really high capacity in watt hours, and allows for a more robust case design that doesn't have the structural weakness of a battery door.

              And if you put the pouch cell on a set of wires with a small pluggable connector to the main PCB (and a case that can screw open/shut) it's still an item the user can replace with 5 minutes and a screwdriver if it wears out from many cycles over a period of years.

              • iamnothere 6 minutes ago

                > And if you put the pouch cell on a set of wires with a small pluggable connector to the main PCB (and a case that can screw open/shut) it's still an item the user can replace with 5 minutes and a screwdriver if it wears out from many cycles over a period of years.

                True, and you could even enclose it in a quick swap hard shell case with contacts, like the old Nokia cell phone batteries. (Those are actually still good for some uses, I have a gadget that uses them.)

                We’re fortunate to live in an era of battery abundance.

      • jsisto 3 hours ago

        How is a 10000mAh pouch more energy dense than an 18650?

        • bri3d 3 hours ago

          By not having void air space in between cylindrical cells like you'd get with two 18650s? It's mostly just a matter of packaging.

          Pouches can be made to have better volumetric density than cylindrical cells quite easily, which is why laptops aren't generally full of cylinder cells anymore; the challenge is just providing them enough external support/compression and swelling allowance, which can be accomplished through chassis design.

        • iamnothere 3 hours ago

          Pouch cells are lighter per mAh due to the lack of metal casing. But more than the casing, the form factor is better for a pocketable device. The cylindrical form factor sticks out, usually wastes some space, and can’t be neatly tucked behind a board or display.

  • notpushkin 4 hours ago

    This is really nice! It so happens that I’ve just bought a $10 4G dongle [1], guess I’ll have to check what’s inside now :-)

    [1]: like this: https://img.joomcdn.net/ea91b4418997d83d802339fad0bbcf878b9d...

    ---

    Aside, but it appears some MSM8916-based dongles run Android UI despite having no display: https://github.com/u0d7i/uz801#screenshots

  • harhargange 5 hours ago

    I often ditch my phone and carry my hotspot device for my internet. The only drawback is that for viewing my texts and OTPs i end up putting the sim in my phone or opening up the web interface on my laptop. This seems to work very well as a dumbphone per se.

    • newhotelowner 5 hours ago

      How do you check sms/OTP/text using web interface on your laptop?

      • notpushkin 4 hours ago

        This probably depends on your particular dongle model. Back in 3G era, some carriers offered USB modems with SMS locked out in the firmware, but you could flash a firmware from a different operator (also install their variant of software, the only difference being the added SMS tab and a different skin) and then you can text and even use USSD! (No calls, though.)

      • knowaveragejoe 4 hours ago

        https://messages.google.com/web/ is one way I'm aware of, I'm sure there's others depending on the messages app used.

        • notpushkin 4 hours ago

          It seems those modems run Android 4.x with the stock messaging app: https://github.com/u0d7i/uz801#screenshots

          But I guess you can install a custom messaging app that would sync the messages? (If there’s one that still supports such an old version of Android)

    • blobbers 3 hours ago

      If you move to an Apple set up, the phone can act as a hotspot and there is no need to take out your sim. Also... you have a physical sim card? I thought those became obsolete.

  • xx_ns 6 hours ago

    This is a really cool project! A mini cyberdeck that doesn't seem too impractical to use. Repurposing the Clicks keyboard is a genius idea.

  • VinnyBarreca 3 hours ago

    It would be pretty cool to put Hermes Agent or some agent system on that thing, assuming the OpenStick build has enough RAM/storage. That would be fire.

    • RIMR an hour ago

      Truly, I couldn't imagine a worse platform to put a coding agent on. What even would be the point?

      It's got less than 512GB of RAM, no package manager, and virtually no storage.

  • msm8916 2 hours ago

    OpenStick is super old though, there are Linux and OpenWRT builders that track the upstream kernel, check hkfuertes and others.

  • dgf18 5 hours ago

    Really cool!