Why get an expensive Pi when I have an old phone?

Nowadays, I just get old laptops with broken screens and take the mainboard out. They are dirt cheap, often even have 16GB of RAM, you can just dump pretty much any linux on them and they are usually way faster than Pis.

The boards are of course bigger, which I guess will be a non-starter for many. They'll also require active cooling unless you downclock them considerably. They often also require more power, although many mainboards can be configured down two a few watts of power consumption, depending on what peripherals and speed you need.

Yeah, it's more work than just getting a Pi, but given the current prices, it makes sense for me.

This is the main issue:

> 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.

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.

This isnt new and has a major flaw. Phones are not made to be continously charged. You have to find or tinker your own solution to power it without battery which is more cumbersome than just getting off the shelf used hardware in the raspberry range.

> Why get an expensive Pi when I have an old phone?

Because the pi has a maintained kernel and a userspace I don't have to fight.

I tried this once - with a little "fleet" of phones running 24/7 serving things. But it turned out that phones do not really like running 24/7 doing something. Eventually they started failing in various ways.

Is there a project that can handle GPIO from a USB port? To me that and a generalized linux distro for phones is would be the compelling switch.

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.

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.

There are a few issues with Android devices. I have 2 Android phones lying around in my rack, as well as an Android tablet that I use as a dashboard.

1. Batteries swell over time. Replacing them is easy, but it's still harder than changing one inside a UPS hat. Most phones won't even start without a battery.

2. Software support will be awful. Maybe you'll get lucky and your device will be able to run postmarketOS.

3. There's no modularity, you're stuck with the full package. Don't feel comfortable having a camera or a microphone on a device with no security updates? Too bad, there's not much you can do about it.

Don't get me wrong, if you understand these risks, are fine with them, and Android devices cover your use cases — that's great, go for it! I just find SBCs with decent software support to be a better option for general projects.

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.

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

Underrated bit: it has its own LTE modem and battery. Makes a decent watchdog for when the router or power dies and the Pi goes down with it.

Because big tech decides what you are allowed to run on your phones

I was thinking about using my old phones with something similar, but I'm worried about battery. When permanently connected to charger, won't they swell, start fire or something like that after longer(er) period of time?

Way more trouble than it is worth.

* Lithium batteries are a problem

* No ethernet

* No prebuilt images like say Talos

* Can't readily attach an SSD

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...

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.

Phones are cheap for what you get, but problems arise when you try to add something. Driving LEDs is the start. So how do you do that? Via a cloud service? How do you add an air monitor or servos? The pi and esp32s have an ecology of add-ons and a community to support you. Sure that could be built around a rooted phone, but it would take years.

Yeah, people mostly just buy things to satisfy their wants. the PI sells because its the more reliable, low-friction option for a lot of use cases,even if an old phone is technically stronger and cheaper

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.

Hey, I can answer that! Because me and my family have always had Verizon and when I recently went through alllllll the devices I have ever owned, I would need to go back to circa 2010's Galaxy S7 to be able to get a rooted device, which as Claude keeps reminding me, "isn't what I want, but might be good enough"....

Raspberry PI's don't give me near the struggle and I never dumbly signed a contract that I didn't really own the device I was purchasing (that I am completely aware of)

Pi's are expensive trash

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].

[1]: https://blog.denv.it/posts/pmos-k3s-cluster/

kernel wont get updates, no IO, no ports.

Need to fuck about pretty much per phone model,rather than install Debian, unattended-upgrades and forget about device for 2 years

Are you gonna open-source this so others can also benefit?

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?

https://nimitbhardwaj.github.io/posts/hermes-agent-rooted-an...

I too have a bunch of cheap android phones of diverse vintage lying around.

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.

Locked bootloaders mostly

>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.

I also keep using old android phone but the battery dies every few months if you keep plug-in power cable.

What about GPIO support and Raspberry Pi OS updates?

Why get an expensive Pi when you can get a cheap 1L PC / tini-mini-micro or SFF pc? Especially if you don't need GPIO pins?

My blog article about this: https://louwrentius.com/the-raspberry-pi-5-is-no-match-for-a...

An old phone? That is my phone, sigh...

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.

I've always found it a bit absurd that an old phone can have more sensors and connectivity than a fairly expensive hobbyist computer, yet we rarely consider using it as one

but aren't the cell carriers making loads of money off our data? lol

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.

A Pi is the Apple of small compute. It's the in thing, flashy, with loads of just as capable competitors.

No one cares if you have overpriced white earbuds or not for Pi tasks.

Is there a peripheral you can plug into the USB port that exposes gpio pins?

[dead]