The top comment should be that without opening the case and wiring in the power directly (not easy) for such old phones THIS IS DANGEROUS. The battery, when under load and plugged in the whole time, can and will swell and explode somewhere in the future.

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.

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.

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.

>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 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.

Even better are old smartphones with Sailfish OS, Ubuntu Touch or PineOS - they are based on proper Linux with full control, not crippled like stock Android, unless you flash it (if you can).

This is valid for one off projects but if you want something that can replicate/scale and easily integrate into a product then RPi or Jetson boards are great

Old phones are fine if you want to tinker but are a nightmare to try and actually 'do' something with. It sucks and shouldn't be the case but here we are.

Depends on what you want to do. In terms of ram and CPU I understand but if you want HDMI, I/O... And lot of documentation about existing projects, troubleshooting....