I have a few old smartphones lying around collecting dust, but there's a lot you can actually do with one if it's just sitting there. Most smartphones in the last few years are incredibly powerful, and even without rooting them, there's a lot you can do. However, most of these projects require root access as they can give you even more control over your phone to run whatever you want.

I used a OnePlus 11 I had lying around for this, which is a bit more powerful than your conventional old phone that may be lying around. Still, any older phone can do most of these, along with plenty more, so it's worth having a look and seeing what you can do!

5 Pi-hole

Filter advertisements on your network

Pi Deploy is a fork of an older root application for Android called Linux Deploy, but its use case is a bit different. Rather than being aimed at running general-purpose Linux distributions, Pi Deploy is built to run Raspbian on your smartphone. However, there's one very specific reason for that, and that's for Pi-hole. Pi-hole is a network-level ad-blocker that runs a DNS server on the device hosting it. If you use another device and set your DNS server to the one running Pi-hole (in this case, our trusty OnePlus 11), you can filter advertisements across your entire network.

How Pi-hole works is it will see those DNS requests for advertisement servers and route them to a blackhole, so that client devices like your browser can't actually load the advertisements. It's a great way to get use out of your old phone, and can also be used to block trackers and other unwanted, potentially privacy-violating baddies online.

4 Turn your old phone into a Nextcloud server

It's really easy with root

Pi Deploy's Raspbian build also comes with a script to build and launch a Nextcloud Pi server. Nextcloud is a fantastic way to build your own Google Drive alternative that you can host yourself, and other devices can sync to it as well. It doesn't take long to set up, and with Pi Deploy, you can SSH in and just run pideploy-nextcloud-install to set up and install Nextcloud Pi. Nextcloud Pi runs a bit behind regular Nextcloud releases but configures and runs your server for you.

Nextcloud serves as an excellent Google Drive replacement that you can set up in just a few minutes. The Nextcloud ecosystem offers a wide range of applications, including a full Google suite alternative through Nextcloud Office. We don't recommend relying on your smartphone's storage as your only backup medium, but it works as a place to store files and make copies in a pinch.

3 Minecraft server

You don't even need root for this one

Did you know you can run a Minecraft server on your phone, and without root? It's pretty easy! You'll need to use Termux and AnLinux to install a virtualized version of Ubuntu that you interface with through Termux. It's very basic, but with smartphones being as powerful as they are these days, it's surprisingly viable. You'll need a way to give access to your friends so that they can play with you, but that's about it.

If you have a rooted phone, then this process can be made even easier by simply deploying a full-fledged Linux distribution on your phone.

2 Run Linux

Run a full Linux system on your phone

There are a few ways you can run Linux on your phone, but the best way is to either use a proot Distro or a tool like Linux Deploy. Linux Deploy is somewhat outdated and may have inconsistent results on different smartphones and different versions of Android, but it will be more akin to a full Linux distro. In contrast, a proot Distro can work for basic things, but it's not cut out to be used as a replacement for a true Linux build.

proot isn't stable and can have degraded performance, and there's no real access separation. The difference between a root user and a regular user is just the UIDs and names, rather than a true separation of control. That won't matter for basic things, but if you're serious about using Linux on your phone, we recommend looking into Linux Deploy. From there, you can try to run servers and other applications, including Docker if you feel comfortable modifying your phone's kernel.

A program like Nestbox would be better for this, especially if you're using a Google Pixel.

1 CCTV camera

Just make sure it's plugged in

This also doesn't require root and can make your smartphone a part of your overall home security. While we don't recommend using it for long periods of time as it will generate a lot of heat and degrade your battery, IP Webcam can create a web server that streams your phone's camera to it. You can configure what camera it's using, you can enable motion detection, and you can even take photos remotely so that you can save whatever is going on.

To this day, IP Webcam is still a fantastic app that can get you started, and it even has Home Assistant integration. if you're serious about making it a part of your home security, you might want to invest in some ways to charge your devices in a smart way rather than keeping them at 100% all of the time.

If you have an old phone lying around, brainstorm what you can do with it

Leaving old tech to go to waste is bad, and you can find plenty of uses for older devices that can teach you something new and save you money. That's what this is all about, and even running a Minecraft server can save you a monthly subscription price if you were to purchase a Minecraft Realm or other rented server instead. There's a lot more you can do, but these are the ones that I've personally done, and I recommend trying them out at the very least!