Well that's because for the Pi you have GPIO. If you just want to run homelabs or software only stuff, why not go for ITX motherboard with just in time components
Thats a great read. I explored similar things with my rooted phone. Samsung galaxy m30s. Wrote something on it as well on what I did, may be you will also like this type of experimentation?
I guess in general, the development experience on a Pi is much better, because it’s made to be tinkered with, right? In the other hand, Android phones are also nicely hackable. I’d just guess that for beginners, it’s much easier to install the Raspberry IDE and plug in the Pi (as opposed to learning how to connect and develop for an Android phone). But yeah, for pros or vibe coders, an Android phone might be the right or even better choice. And it’s great that Android phones can therefore be used a little longer before landing in a landfill.
> The open question is supply. Finding two good used phones is easy; finding a few hundred matching ones, with healthy batteries and predictable camera behaviour, would take more work. I feel increasingly confident that it’s possible.
RaspberryPies and such are commodity hardware. You can buy one, two, ten, twenty, a hundred, and it just scales along. All of those devices will, barring perhaps a few dead-on-arrival ones covered under warranty, just work out of the box.
A used smartphone will have issues which can vary from device to device, so scaling that would take a very dedicated refurbishing setup where the quirks are ironed out (and the unsalvageable ones discarded).
I would also expect that you are starting out at the other end of the bathtub curve: with new devices you will have a few that fail soon after unboxing and using them a bit, and then they will run fine for years until you start hitting the other end of the curve and wear-related faults pop up. With old cheap phones you would start out at that side of the curve, so if you buy one hundred of those, a bunch will fail at various points soon after deploying them.
The cost of that unpredictable behaviour seems high to me. So much so that I wonder if it wouldn't be cheaper to buy a lot of unsold stock of a certain type of budget smartphone from two or three years back. Those devices could run fine as long as they aren't connected to the internet directly.
Phones are pretty robust though, meant to handle everyday use and abuse. In terms of failure, the battery is really the only thing to be concerned about. Most phones have some battery limiting option, and bypass the battery when the charger is connected. And if you're determined enough you can run without a battery.
Just plug all the battery slots in parallel to a 4.1V power source (that's a nearly full battery voltage). You probably have to solder them to make a reliable connection.
I'm pretty sure the third/fourth pins are used for communication to the battery. I doubt the phone would be happy it wasn't responding. I vaguely remember some phones can just use a resistor for that pin? Either way it's not quite that simple.
Maybe. Try it and see. If it doesn't work it's probably just a temperature sensor (thermistor) and a resistor indeed simulates a certain temperature the same way your power supply simulates a charge state.
You could probably open the wrap of a battery to show the individual components including the cells and other guts. Once you identify what the cables lead to then simulate it or replicate it.
The main issue with old phones are NAND Flash degradation and battery problems. As long as you fix those two issues everything else is simple. These days with AI it's almost trivial to build and flash your own ROM and even the most hardcore of binary blob drivers can be reversed so long you have enough GPUs.
It's not the dark days of android where something like CyanogenMod takes a whole team of experienced system and embedded engineers to port and you don't have to hunt for information on XDA anymore.
Hobbyist don't usually need to scale beyond one device. Warranty is not that a big issue, if you buy a used hardware you know what are getting into, that's why they are cheaper than new devices.
we are talking about embedded devices here. you dont need a second one because your web server cant serve enough requests, you need a second one because you want separate projects to have separate hardware.
> RaspberryPies and such are commodity hardware. You can buy one, two, ten, twenty, a hundred, and it just scales along.
Not my experience at all. Pies are hard to find, get more expensive each week. Some are impossible to find (Pi zero).
The most fragile part of a phone is the screen. If you don't care about breaking it, then access to the battery becomes pretty easy, and therefore easy to replace.
Where are you based? I just bought 25 from CPC without any issues. Delivered in two days. They aren't as cheap as they used to be, but I understand the reasons why, given how expensive RAM is. Yes, the zero is trickier, but the 2W is in stock on PiHut at the moment.
Thank you so much for the heads up! They're as 'rare as rocking horse ...' as an old teacher of mine would say. And I've needed one for a project for ages.
Unfortunately thanks to the EU's new tariff regime it would cost over 30eur to ship it here, but luckily I can smuggle one back from my next trip to the UK...
I've chatted to the guy running Citronics, they provided old but working Fairphone 3 to a workshop we had at Goatmire Elixir. They try to tackle repurposing and certifying the quality of old phones. Interesting effort and well positioned for the current climate.
Their board currently on sale is this. Based on Fairphone 2. Targeting commercial or industrial more than hobbyist though. I've been trying to convince them to sell the old phones as is, as well.
https://shop.citronics.eu/
Thanks to Marc Lainez and his token spend we have a great Nerves system for running the Fairphone 3 by just programming Elixir. And people are flipping new (old) phones over to be put to work every week in the Nerves Discord.
We have a good UI framework in Emerge. We have media handling with Membrane. And Nerves handles the OS integration for stuff like networking. I thoroughly enjoy making up my own mobile OS for my own purposes.
You lose the GPIO/I2C/SPI/UART as easy extension points compared to the Pi. But the stuff that is there is already well integrated.
Yeah like its a weird article idea where the pi is expensive compared to an old phone which you have for free. But that doesn't make the used phone cheaper. You can just as well say why use an expensive PI when I have an old computer with a 1680ti and 12 gigs of ram. Like yeah okay but what does that have to do with Pi? Entirely different device classes imo
You're correct but they did lay out the table oddly because the first line has the price for the Pi but not the phone, which made it look like it was assuming they already had the phone.
> Yeah like its a weird article idea where the pi is expensive compared to an old phone which you have for free. But that doesn't make the used phone cheaper.
Perhaps not in the first world reality you live in, where you can buy a rpi 4 for a couple of bucks. But in third world countries they aren't readily available and usually the imported prices exceed that of a decent PC.
You can find an old used phone for almost half the price that is still good enough for many daily processing tasks.
> You can just as well say why use an expensive PI when I have an old computer with a 1680ti and 12 gigs of ram.
That is a logical fallacy. A high end PC and an old used phone that you can buy in Ebay are in entirely different price ranges.
> Like yeah okay but what does that have to do with Pi? Entirely different device classes imo
Entirely different device classes, yeah, but both can execute the very same functions. The difference is one is much cheaper and you get 2x the processing power than the "more specialized" other. You can use both as local llm, serv
ers, home automation... and even GPIO if you expose some wires from the phone.
Yes, the terms "kernel" or "security updates" don't exist in the article at all.
Everything without upstream kernel support is inherently vulnerable.
This is why most phones are unfortunately not general purpose computers. They don't run the software you want, but only work on closed binary blobs hardcoded against specific kernel versions.
If only we had some magical software that could compile the vanilla Linux kernel, diff it with the vendor kernel, reverse engineer the differences and patch the original sources for you while you sleep...
I’m out of the loop on this sort of workflow. I guess this is referencing the LLMs super reverse engineering capabilities. They are impressive but how much would that sort of task cost? There isn’t a ton of headroom if we’re going to beat a Pi, right? I mean they aren’t super cheap anymore, but you also have to factor in the phone.
You can reverse quite a large program on a Claude $100 sub if you already have one lying around. I have to assume it's cheaper if you have the sources of a kernel that's 99.99% the same.
In the long run I also imagine this sort of thing being something someone does once per phone model and uploads it.
Often enough for those android devices you already have the sources for most components but only compatible with some age old android kernel and it's "just" porting it and poking around. LLMs are quite good at this.
Yes, USB to GPIO adapters are available. Note that you won't be able to implement anything that has timing requirements - you'll need a microcontroller for that.
I think in practice the timing jitter and the low cost difference to something like an Arduino Nano or Pi Pico means people use one of those even if they could technically use a GPIO adapter.
Rooting or flashing a modern phone is pain in the ass. Ideally the battery needs to be replaced with a 3.7V PSU (and BMS must be salvaged without cutting the battery accidentally). And for old phones it either old linux kernel, partially unsupported hardware or fork maintained by handful of hackers for free.
I guess laptops are way easier: more upgradeable and repairable, don't require unlocking mostly, battery can just be thrown away and it works with its native PSU. Just need to make sure power won't go out. And it is bulkier, though maybe less susceptible to overheating.
Agreed, dealing with deprecated android devices can be frustrating even when rooted. There was a project to bring a standard deb linux distro build to native mobile hardware, but most features like cell data access become a brick.
It is the drawback of locked proprietary hardware builds no one makes anymore.
An recent laptop with a broken LCD is cheap e-waste, and works just fine to setup on an external monitor. Mini PC are also cheaper than most pi5 now, so if you don't need the gpio... save the money for a real SSD. =3
Reasons to get a Pi: GPIO support, software support, OS updates, free root & bootloader, more flexibility and customizability, extensive documentation and support, consistency, simplicity, more ports, battery optional.
Used phones are good for tinkering, especially for "display with sensors and battery attached" usecases, but there are still plenty of downsides. And unfortunately Linux on phones is just not ready for primetime, last I checked.
Atom x5 Z-8350, 2GB of RAM, 8-16GB of flash, some USB, and there's a board on that page you can have done up to do a slapdash SD adapter inside the case for more flash.
The main reason is that they are one of the few ARM computers sold with a pre-installed officially supported GNU/Linux distribution, at affordable prices.
Even with the prices increases that the PI has suffered, there no systems of vendors like Tuxedo, or System 76, at similar price point, with ARM support.
As long as it's not an iPhone. Once Apple has bricked your old iPhone, you can't even run your own software on it anymore. Despite all their lip service to being environmentally friendly, that thing is nothing but an expensive paperweight and e-waste now.
You could consider getting an older flagship phone perhaps 2022-2023 and have a strong portable device with a decent amount of compute power and not to mention ram. I'm starting to believe that these devices are under utilised and we will see some interesting applications using either with AI or without.
I particuarly think the economics of this are interesting, if you take the one plus 11 you can get one for around £200-250. The CPU is very capable and the alternatives are a PI 5 or N100. You get 16b of ram, a screen, gps, bluetooth a camera... the list goes on.
These devices could really shine as edge computing devices and I believe they are overlooked.
The problem with modern smartphones is that they run on battery, even when plugged into external power. You cannot use it without the batteries without some more hardware hacks. As the batteries aren't designed to be always in a fully charged state, if you decide to use the phone with the battery you have to carefully monitor the batteries too if you keep it powered 24x7. Old batteries can also bulge or, worst case, even explode. Another thing you need to consider is cooling - Smartphones are designed with the idea that their CPUs won't run at 100% always. A smartphones CPU, Camera, battery etc. tends to get hot on prolonged use, so if you are, for example, planning to use it as a mini webserver or as a 24x7 streaming cam, you need ensure it remains adequately cool. And ofcourse, the best smartphones for these kind of projects is one capable of running Linux.
Some OnePlus devices have a "bypass charging" system. My OP8 Pro is running since 2y now as a Kubernetes node, and nothing bad has happened to its battery (yet).
I'm honestly curious to see if bypass charging is on, but it's been a while since I touched the device itself and it has been fine do far. YMMV
>>The problem with modern smartphones is that they run on battery, even when plugged into external power.
That's not universally true - a lot of android phones have a "bypass charging" mode where you run directly from the power supply, and indeed you can run them with the battery removed.
I think sometimes playing games on the phone while plugged in would actually drain battery because the CPU just used too much power (obviously a while back when charging was lower power).
Not sure if those phones would work without a battery and throttle the CPU, or if they would crash.
On a similar note, old smartphones (depending how old of course) are way more powerful than a Raspberry Pi. You can turn them into a Kubernetes cluster [1].
I recently used Termux on a 7 year old low-end android to run a WordPress site with sqlite db and a golang sse pubsub service at a conference, via cloudflare tunnel, with dozens of people connected and doing some realtime collaborative stuff. Worked perfectly.
It was vastly more powerful than the old RPi 3 that i have, and significantly easier to work with given the screen, keyboard, wifi etc...
For me if I don't have a need for the GPIO pins, it's "why get an expensive pi when I can get a used ex-corporate small form factor quad core, intel core i7-something desktop PC with 16GB of RAM and a real SSD"... For like 150 bucks on eBay. RAM apocalypse and price of equipment has affected this a lot (these used to be like 90 bucks depending on era of core i7), but they're vastly more useful when a general purpose x86-64 linux is installed on them. Or even just put proxmox on it and then various things inside that.
>Why get an expensive Pi when I have an old phone?
>I’ve unlocked and rooted the Redmi
Herein lies the issue. I don't know fuck all about phones. I don't want to. They are engineered to keep me out, and that is a pain in the ass I don't want to deal with when doing hardware work. I want to own something that works the second I get it and doesn't fight me the entire way. Sure, I could let an LLM guide me through it or even do it for me, but why bother when the whole point of the hardware is for me to fuck off and use it as a subscriber to the OEM and carrier? This is tedium, removed by further spending. Not to mention documentation - what bullshit is the OEM hiding in their board or firmware thats going to ruin my day? I'm sure that some of these devices are great for reuse as a self contained server with media and modem, but _is my old phone going to do this?_
I'm not gonna spend $50 on ewaste to _try_ to do something unless I _want_ to use _that_ ewaste (old keyboards, old toys? :3). Old phones are a non-sequitur because, again, they're engineered to keep me out.
>>Herein lies the issue. I don't know fuck all about phones. I don't want to. They are engineered to keep me out, and that is a pain in the ass I don't want to deal with when doing hardware work.
I mean, you do know we're on a forum called hacker news, right?
In most cases it's not some magic voodoo process that you need an LLM for, it's the first result on Google and one command to run or in some cases you just hold two buttons together when booting up and click the unlock button.
Like, I completely understand your perspective and desire to have things which "just work"(I'm in the same boat a lot of the time lately) but like, let's be realistic - rooting an old phone and running some software on it is really not a big deal, I'd hope especially for people on here.
I have recently taken to gathering old phones and putting Nerves on them (Nerves packages up the Erlang VM into a mainline kernel to run on a variety of devices). I got inspired by a talk by Marc Lainez at Goatmire who had put it on a variety of exotic devices (e.g., a Wii).
I am by no means an expert at this, but starting of with a device on the Postmarket OS list and Claude, you can get a lot of these old devices working with mainline Linux and nearly all drivers. The newer devices are a bit harder, but if you go back nearly a decade, they're very easy to get working.
So far I have repurposed a Fairphone 3, Nexus 5, Galaxy S20, and Galaxy Tab 3.0 7". All of them (except the s20) with all drivers working compared to stock. Others have done a lot too: https://github.com/mlainez/awesome-nerves-systems
For DIY projects you can use host USB, or get one of the Adafruit FT232H type boards for GPIO pins.
Neat. I've heard good things about Erlang, though I haven't taken a proper look at it. What kind of things can you do with it? Or rather, where does it shine?
So Nerves folks typically run Elixir on the Erlang VM. So you have the Phoenix web framework, Membrane media framework, Nx (nx_eigen) for basic inference, Emerge does well for embedded UI.
I've played around with clustering a bunch of these devices over Tailscale across my home. Opening cameras from one device and streaming to anothers display, willy-nilly. All experimental for me.
I've put Homex and Espex on them to have them integrate with Home Assistant. Feeding sensor data up or whatever I feel like.
Elixir already has a production embedded ecosystem through Nerves and web services have been the bread and butter for a long time. So you can do almost anything.
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[ 0.19 ms ] story [ 44.4 ms ] threadhttps://nimitbhardwaj.github.io/posts/hermes-agent-rooted-an...
> The open question is supply. Finding two good used phones is easy; finding a few hundred matching ones, with healthy batteries and predictable camera behaviour, would take more work. I feel increasingly confident that it’s possible.
RaspberryPies and such are commodity hardware. You can buy one, two, ten, twenty, a hundred, and it just scales along. All of those devices will, barring perhaps a few dead-on-arrival ones covered under warranty, just work out of the box.
A used smartphone will have issues which can vary from device to device, so scaling that would take a very dedicated refurbishing setup where the quirks are ironed out (and the unsalvageable ones discarded).
I would also expect that you are starting out at the other end of the bathtub curve: with new devices you will have a few that fail soon after unboxing and using them a bit, and then they will run fine for years until you start hitting the other end of the curve and wear-related faults pop up. With old cheap phones you would start out at that side of the curve, so if you buy one hundred of those, a bunch will fail at various points soon after deploying them.
The cost of that unpredictable behaviour seems high to me. So much so that I wonder if it wouldn't be cheaper to buy a lot of unsold stock of a certain type of budget smartphone from two or three years back. Those devices could run fine as long as they aren't connected to the internet directly.
It's not the dark days of android where something like CyanogenMod takes a whole team of experienced system and embedded engineers to port and you don't have to hunt for information on XDA anymore.
It makes more sense with high availability though. Their current situation seems rough.
Not my experience at all. Pies are hard to find, get more expensive each week. Some are impossible to find (Pi zero).
The most fragile part of a phone is the screen. If you don't care about breaking it, then access to the battery becomes pretty easy, and therefore easy to replace.
Unfortunately thanks to the EU's new tariff regime it would cost over 30eur to ship it here, but luckily I can smuggle one back from my next trip to the UK...
Their board currently on sale is this. Based on Fairphone 2. Targeting commercial or industrial more than hobbyist though. I've been trying to convince them to sell the old phones as is, as well. https://shop.citronics.eu/
Thanks to Marc Lainez and his token spend we have a great Nerves system for running the Fairphone 3 by just programming Elixir. And people are flipping new (old) phones over to be put to work every week in the Nerves Discord.
We have a good UI framework in Emerge. We have media handling with Membrane. And Nerves handles the OS integration for stuff like networking. I thoroughly enjoy making up my own mobile OS for my own purposes.
You lose the GPIO/I2C/SPI/UART as easy extension points compared to the Pi. But the stuff that is there is already well integrated.
Some are bought with US carrier locks - never activated or unlocked. Any chance they can be unlocked with today's tools and not dumped into ewaste.
There are a few simple projects for home automation i have in mind but the rooting felt like a daunting task.
Because the pi has a maintained kernel and a userspace I don't have to fight.
Perhaps not in the first world reality you live in, where you can buy a rpi 4 for a couple of bucks. But in third world countries they aren't readily available and usually the imported prices exceed that of a decent PC.
You can find an old used phone for almost half the price that is still good enough for many daily processing tasks.
> You can just as well say why use an expensive PI when I have an old computer with a 1680ti and 12 gigs of ram.
That is a logical fallacy. A high end PC and an old used phone that you can buy in Ebay are in entirely different price ranges.
> Like yeah okay but what does that have to do with Pi? Entirely different device classes imo
Entirely different device classes, yeah, but both can execute the very same functions. The difference is one is much cheaper and you get 2x the processing power than the "more specialized" other. You can use both as local llm, serv ers, home automation... and even GPIO if you expose some wires from the phone.
Everything without upstream kernel support is inherently vulnerable.
This is why most phones are unfortunately not general purpose computers. They don't run the software you want, but only work on closed binary blobs hardcoded against specific kernel versions.
In the long run I also imagine this sort of thing being something someone does once per phone model and uploads it.
I think in practice the timing jitter and the low cost difference to something like an Arduino Nano or Pi Pico means people use one of those even if they could technically use a GPIO adapter.
No one cares if you have overpriced white earbuds or not for Pi tasks.
I guess laptops are way easier: more upgradeable and repairable, don't require unlocking mostly, battery can just be thrown away and it works with its native PSU. Just need to make sure power won't go out. And it is bulkier, though maybe less susceptible to overheating.
It is the drawback of locked proprietary hardware builds no one makes anymore.
An recent laptop with a broken LCD is cheap e-waste, and works just fine to setup on an external monitor. Mini PC are also cheaper than most pi5 now, so if you don't need the gpio... save the money for a real SSD. =3
Used phones are good for tinkering, especially for "display with sensors and battery attached" usecases, but there are still plenty of downsides. And unfortunately Linux on phones is just not ready for primetime, last I checked.
https://www.ebay.com/itm/147663241534
https://www.parkytowers.me.uk/thin/wyse/3040/
Atom x5 Z-8350, 2GB of RAM, 8-16GB of flash, some USB, and there's a board on that page you can have done up to do a slapdash SD adapter inside the case for more flash.
I do use termux daily to ssh into other boxes, that's incredibly useful
Even with the prices increases that the PI has suffered, there no systems of vendors like Tuxedo, or System 76, at similar price point, with ARM support.
I particuarly think the economics of this are interesting, if you take the one plus 11 you can get one for around £200-250. The CPU is very capable and the alternatives are a PI 5 or N100. You get 16b of ram, a screen, gps, bluetooth a camera... the list goes on.
These devices could really shine as edge computing devices and I believe they are overlooked.
I'm honestly curious to see if bypass charging is on, but it's been a while since I touched the device itself and it has been fine do far. YMMV
See: https://blog.denv.it/posts/pmos-k3s-cluster/
That's not universally true - a lot of android phones have a "bypass charging" mode where you run directly from the power supply, and indeed you can run them with the battery removed.
Not sure if those phones would work without a battery and throttle the CPU, or if they would crash.
My blog article about this: https://louwrentius.com/the-raspberry-pi-5-is-no-match-for-a...
[1]: https://blog.denv.it/posts/pmos-k3s-cluster/
It was vastly more powerful than the old RPi 3 that i have, and significantly easier to work with given the screen, keyboard, wifi etc...
>I’ve unlocked and rooted the Redmi
Herein lies the issue. I don't know fuck all about phones. I don't want to. They are engineered to keep me out, and that is a pain in the ass I don't want to deal with when doing hardware work. I want to own something that works the second I get it and doesn't fight me the entire way. Sure, I could let an LLM guide me through it or even do it for me, but why bother when the whole point of the hardware is for me to fuck off and use it as a subscriber to the OEM and carrier? This is tedium, removed by further spending. Not to mention documentation - what bullshit is the OEM hiding in their board or firmware thats going to ruin my day? I'm sure that some of these devices are great for reuse as a self contained server with media and modem, but _is my old phone going to do this?_
I'm not gonna spend $50 on ewaste to _try_ to do something unless I _want_ to use _that_ ewaste (old keyboards, old toys? :3). Old phones are a non-sequitur because, again, they're engineered to keep me out.
I mean, you do know we're on a forum called hacker news, right?
In most cases it's not some magic voodoo process that you need an LLM for, it's the first result on Google and one command to run or in some cases you just hold two buttons together when booting up and click the unlock button.
Like, I completely understand your perspective and desire to have things which "just work"(I'm in the same boat a lot of the time lately) but like, let's be realistic - rooting an old phone and running some software on it is really not a big deal, I'd hope especially for people on here.
I am by no means an expert at this, but starting of with a device on the Postmarket OS list and Claude, you can get a lot of these old devices working with mainline Linux and nearly all drivers. The newer devices are a bit harder, but if you go back nearly a decade, they're very easy to get working.
So far I have repurposed a Fairphone 3, Nexus 5, Galaxy S20, and Galaxy Tab 3.0 7". All of them (except the s20) with all drivers working compared to stock. Others have done a lot too: https://github.com/mlainez/awesome-nerves-systems
For DIY projects you can use host USB, or get one of the Adafruit FT232H type boards for GPIO pins.
So Nerves folks typically run Elixir on the Erlang VM. So you have the Phoenix web framework, Membrane media framework, Nx (nx_eigen) for basic inference, Emerge does well for embedded UI.
I've played around with clustering a bunch of these devices over Tailscale across my home. Opening cameras from one device and streaming to anothers display, willy-nilly. All experimental for me.
I've put Homex and Espex on them to have them integrate with Home Assistant. Feeding sensor data up or whatever I feel like.
Elixir already has a production embedded ecosystem through Nerves and web services have been the bread and butter for a long time. So you can do almost anything.