[HN Gopher] Putting an Ultra-Tiny Linux Board in a Phone Charger...
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       Putting an Ultra-Tiny Linux Board in a Phone Charger Eventually
        
       Author : rbanffy
       Score  : 105 points
       Date   : 2021-05-06 11:06 UTC (2 days ago)
        
 (HTM) web link (hackaday.com)
 (TXT) w3m dump (hackaday.com)
        
       | withinboredom wrote:
       | Neat! If it's a phone charger, instead of WiFi, why not work as a
       | USB host and use the phone's internet via tethering?
        
         | valyagolev wrote:
         | I assume because it would be more obvious to detect?
        
       | vvll wrote:
       | Why not just buy something like this off aliexpress? I don't have
       | one but I'd assume it'd be pretty easily hacked to run linux (or
       | maybe it does already?) given it already has a camera and wifi:
       | 
       | https://www.aliexpress.com/item/1005002413810261.html?spm=a2...
        
         | Qub3d wrote:
         | In this case, the lede was buried a bit. The actual source
         | article [0] talks about making this project completely open
         | source and using components optimized for linux and networking
         | from the get-go.
         | 
         | [0]: https://itnext.io/im-putting-a-wifi-router-into-a-wall-
         | charg...
        
       | hans-moleman wrote:
       | " I will ignore the "powered from mains" requirement for this
       | round of the board and feed in 5V elsewhere."
       | 
       | I feel this will be a challenge. The wall wart is the size it is
       | because that's the size of a transformer/rectifier for 120/240 to
       | 5v. Trying to add a Linux machine to that but keep the same size
       | is the tricky part.
        
         | dijit wrote:
         | I'm sure there's something that can be done with Gallium
         | Nitride. The chargers coming from that method are many times
         | smaller than the contemporary. Often you can get a 90w charger
         | where a 40w charger used to fit.
         | 
         | https://www.howtogeek.com/509209/what-is-a-gan-charger-and-w...
        
         | sokoloff wrote:
         | Several smart plugs run OpenWRT already.
        
         | Epskampie wrote:
         | The example he shows is pretty big (but not suspisiously big)
         | https://miro.medium.com/max/720/0*jUoQD3Udknc9b5Lx.jpg
         | 
         | Since there are a lot smaller chargers out there this should
         | still be possible. https://store.storeimages.cdn-
         | apple.com/4668/as-images.apple...
        
         | fy20 wrote:
         | IKEA Koppla chargers would be perfect for this.
         | 
         | https://www.ifixit.com/Guide/IKEA+KOPPLA+Connector+(fix)/126...
         | 
         | I expect you could even fit a Raspberry Pi Zero inside if you
         | replaced the charger electronics with something smaller.
        
         | zibzab wrote:
         | Transformers are fairly uncommon these days due low efficiency
         | and large size.
         | 
         | You can build a much smaller (1-3 cm3) and more efficient
         | system using more modern technology.
        
       | userbinator wrote:
       | Relatedly, here's a _GSM cellphone_ in a package only slightly
       | larger than a normal USB plug:
       | https://news.ycombinator.com/item?id=15676737
        
         | [deleted]
        
         | exikyut wrote:
         | (2017)
         | 
         | So, we could fit phones inside USB connectors, 4 years ago.
         | Nice >:(
        
           | squarefoot wrote:
           | Just slightly bigger, but one could actually build a similar
           | thing at home literally for change coins:
           | https://www.ebay.com/itm/284022359237 (or search for "SIM 800
           | module")
           | 
           | This one is a module that does GSM voice+SMS communication;
           | just add a cheap GPS module if necessary, a small 8 pin uC
           | that speaks serial, some code, a battery and voila. The
           | problem with these devices is that they need a SIM card which
           | I believe needs some form of registration pretty much
           | everywhere, so unless there is some governmental screen to
           | protect you, if you use any SIM based device to spy on others
           | you'll be leaving behind sensitive traces useable to identify
           | you.
        
       | i_have_to_speak wrote:
       | Whatever happened to SheevaPlug [1] ?
       | 
       | [1] https://en.wikipedia.org/wiki/SheevaPlug
        
         | spditner wrote:
         | They're still available in newer forms[1]. Its manufacturer,
         | GlobalScale, is more an ODM for plug computers and provides
         | reference devices.
         | 
         | There are also other smaller full package variants around. I
         | used the Ionics PlugComputers for a PBX project ~8 years ago
         | (no longer manufactured), and still have one of them running a
         | PBX on debian under my desk[2].
         | 
         | [1] https://www.globalscaletechnologies.com/t-products.aspx [2]
         | https://imgur.com/a/YuaLFtc
        
         | techrat wrote:
         | The RasPi eclipsed it in cost, usability, function, specs and
         | performance.
        
       | testmasterflex wrote:
       | Do you guys think Linux on small SoCs are the future?
       | 
       | I've chosen the RPi 0W direction for a bathroom music player
       | (Loodio.com) I'm working on because there are so many
       | possibilities in the software and the goal currently is to make
       | it so small a wall socket can support its weight. That way you
       | never have to think about charging it, can do OTA updates and
       | already supports so much software with Linux.
       | 
       | Perhaps the overhead is too high and you can already do a lot
       | with Arduino etc?
        
         | Apanatshka wrote:
         | Make sure to test your RPi 0W with the Bluetooth speaker you
         | had in mind asap. Mine won't connect to my soundbar, which is
         | complicating my setup for connecting my projector and soundbar
         | wirelessly :(
        
           | testmasterflex wrote:
           | Had some issues with it not showing up on iOS at first but is
           | resolved. (First result on google) So the unit itself is now
           | a Bluetooth speaker as well. Like so: https://www.instagram.c
           | om/p/CNsMwbhlSTj/?igshid=1wre6yuxymaz...
           | 
           | Just added a DAC/Amp + speaker inside.
        
         | the__alchemist wrote:
         | No. Compared to an embedded device running targeted code, Linux
         | will be slow, and consume more power. We're not in a post-
         | computational scarcity period yet - responsiveness and battery
         | life matter.
        
           | Sanzig wrote:
           | It's also much easier to handle applications that require
           | very tight timing (examples: motor control, real-time signal
           | processing) when you're using a microcontroller with bare-
           | metal code or almost bare-metal with a very lightweight RTOS.
        
         | posterboy wrote:
         | a better idea would be to get it to replace the socket, give it
         | a neat face plate.
         | 
         | Actually, you only need to have the input/output in place and
         | plan for the wiring at building construction, because the--
         | literally--biggest problem should be the power converter. Guess
         | that's why you complain about weight, too.
        
           | testmasterflex wrote:
           | Sure but that would raise the threshold for setup a lot for
           | consumers. Maybe viable one day if I get a large order from a
           | hotel chain or similar
        
         | rbanffy wrote:
         | Linux has a ton of pull in this space, but you can still do a
         | lot with thinner RTOSs on smaller, less powerful (and power-
         | hungry) SoCs.
        
           | testmasterflex wrote:
           | Yeah the fact I can SSH into the unit and install just about
           | any services like a web server just makes me happy and I can
           | focus on building cool software instead as if it was a fully
           | featured server.
        
             | rbanffy wrote:
             | It's excellent for development. Being able to have a
             | complete development and debugging toolset inside the
             | target environment is awesome for all sorts of reason.
        
         | vidarh wrote:
         | The RPi 0W is orders of magnitude faster and bigger than the
         | first Linux machines I used as a desktop and even the first
         | Linux machines we used as login and mail servers for an ISP I
         | used to run. We handled dozens of simultaneously logged in
         | users on that machine.
         | 
         | So the overhead of Linux is not the issue, even with modern
         | Linux kernels taking up substantially more space. But the
         | overhead of any given distro may be.
         | 
         | You can certainly get lots of things done with a more basic
         | device, but at this point if the unit cost of an RPi 0W works
         | for you, it's certainly convenient to use something like that.
         | 
         | That said, you can do a lot smaller device and still run Linux.
         | E.g. the smallest device I've run Linux on (and it was no
         | record breaker by any means) had 4MB RAM and 4MB flash, and a
         | mid 1990's low end x86 clone.
         | 
         | The Transcend WiFi SD-cards that I linked to elsewhere also is
         | a good demonstration of how small you can get a Linux machine
         | (or could, almost a decade ago)
        
           | andromaton wrote:
           | faster and *smaller
        
             | vidarh wrote:
             | I should have been more precise - I meant it has magnitudes
             | more storage and memory. My first workstation had 16MB RAM
             | (and we ran X on them) and 400MB hard-drives.
        
         | blihp wrote:
         | It's not an either/or thing or even a particularly new decision
         | point. I generally just ask myself for smaller projects if an
         | OS is justified/worth it? If so, go with a SoC or larger
         | running an OS. If not, go with a microcontroller. All that has
         | really changed is the area of overlap between microcontrollers
         | and SoCs continues to grow so it increasingly becomes a
         | requirements/preference decision vs. only one or the other
         | being possible.
        
         | amelius wrote:
         | One tiny problem: I don't have a wall socket in my bathroom,
         | and I suppose many people don't. And even if they do it's
         | likely occupied by the electric toothbrush.
         | 
         | The future is probably to have the CPU integrated in the
         | speaker.
        
           | testmasterflex wrote:
           | Sure, but afaik new homes do. And the latest prototype we
           | built was battery run but I made a lot of mistakes so I'm
           | starting over with the raspberry and eventually making a
           | battery version again with another mcu.
        
             | amelius wrote:
             | By the way, some portable speakers have a USB charging
             | outlet which you could use as well.
        
               | testmasterflex wrote:
               | When it's time to DFM the plan is to contact a CM that
               | makes portable speakers
        
               | ascorbic wrote:
               | I don't know where you're planning to get it
               | manufactured, but I can recommend a CM in the UK that I
               | used for my own Kickstarter project (vela.io) and have
               | continued to do so for multiple rounds of reorders. I
               | originally found them via an intro from another indie
               | hardware maker who sells high end portable speakers. If
               | you want a chat, send me a DM on Twitter where my
               | username is the same.
        
           | vidarh wrote:
           | Yeah, many places there are specific restrictions on
           | electrical equipment for bathrooms that includes e.g.
           | specific sockets types. In the UK for example, most wall
           | sockets in the bathroom use two prongs and are typically
           | marked "shavers only". You _can_ install three prong sockets
           | that can take normal UK plugs in a bathroom, but they must
           | have RCDs, and must be IP (Ingress Protection) rated, and the
           | equipment to be used must also be IP rated to a certain
           | level, depending on proximity to a bath etc.
           | 
           | As a result, most bathrooms in the UK only have the two-prong
           | shaver outlets, if that.
        
       | ngcc_hk wrote:
       | Unfortunately the ulisp can run only on arduino. Otherwise it
       | would be interesting.
       | 
       | But in the other hand if you just want a hacking device that can
       | be there abd phone home, can arduino-ulisp fit the bill. Wonder.
        
       | Spunkie wrote:
       | Neat.
       | 
       | Should combine it with power line internet for an almost
       | completely unmonitored channel for data exfiltration.
        
         | ekianjo wrote:
         | You can't combine it with power line internet out of nothing -
         | you need an appliance already installed in the first place, and
         | usually the data is encrypted over the power line anyway.
        
           | XorNot wrote:
           | Powerline internet to the fusebox where you turn it into 4G
           | with another device.
        
             | schoen wrote:
             | You could use UPB to signal over the home wiring to another
             | device.
             | 
             | https://en.wikipedia.org/wiki/Universal_powerline_bus
             | 
             | (Well, I guess there are several different protocols in
             | this area, with their respective transceivers available. I
             | used to use X-10, which has a much lower data rate.)
        
             | scoopertrooper wrote:
             | You'd only be able to get access to the fuse box at a very
             | small company or at a residence. Either of which probably
             | isn't monitoring their wifi or cellular (especially)
             | channels.
        
           | monocasa wrote:
           | You can pick up homeplug signals from other houses if you're
           | on the same phase. And the encryption isn't really the best.
        
         | vidarh wrote:
         | There's the good old sdcards with wifi running Linux that seems
         | like they'd be a good candidate for that.
         | 
         | EDIT: This is the one I was thinking of:
         | 
         | http://haxit.blogspot.com.au/2013/08/hacking-transcend-wifi-...
        
         | zeckalpha wrote:
         | Power line internet is very noisy in the RF spectrum.
        
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