When you've got a new smartphone, what do you do with your old mobile phones?

Whether it's an archaic Nokia or a recent Android or iPhone, your phone has some sophisticated circuitry inside. As we move into a world of smart homes and connected devices, your phone's technology is more useful than ever before.

So, while it might be obsolete as a phone, it can still be reused---you just need to get creative. Here are a few ways you can reuse an old cell phone.

1. Get Over Your Tech DIY Fears

One of the best things to do with old broken cell phones is to use them to conquer your fear of tech-based DIY.

For example, you can easily replace a damaged screen yourself—it's really not too hard. But it can be intimidating to try... What if you can't do it? What if you make things worse?

An old phone is a perfect way to get over those fears. You can practice anything you want on an old phone. You can start with something small like jailbreaking an old iPhone, or installing a custom ROM on Android. If you're comfortable with those, try something challenging like disassembling and reassembling a phone.

2. Create an Untraceable Phone

Right now, a hacker can easily trace back all the data from your phone back to you. If you have an extra smartphone, you can turn it into a "ghost phone" that will be completely untraceable.

A ghost phone has a lot of benefits. For example, it will keep your identity secure on online dating sites or if you're selling something on Craigslist.

It's simple to set up:

  • Install one of the apps that provide a burner phone number. The recommended options are Hushed or Burner.
  • Add a secure VPN service that encrypts all data going out of your phone. CyberGhost and ExpressVPN both do this.
  • Create a new Google or Apple account from the phone. Don't sign in with your existing account on the app stores. Similarly, create new accounts for any app you want to use.
  • Don't buy any app or service. Online transactions leave a money trail.

This is a handy gadget to have with you. Any time you want to take a data-sensitive online action, it'll keep you more secure than your everyday phone.

Related: The Best Sites to Sell Your Phone for Cash

3. Recycle the Phone Into a Wallet or Piggy Bank

repurpose-old-phone-wallet

Most of these tricks are useful if you have a functional old phone. But what if it's a busted old clamshell phone or a broken iPhone? Well, you could turn it into the coolest wallet around.

This project requires you to take apart the phone and remove all the gadgetry inside. You just want the outer case, nothing else. As such, it is a great way to reuse old Nokia phones (and other keypad-based models).

Depending on what phone you have, you can now get creative with how you want to use it as a wallet. Instructables has a couple of inspirational guides for this; someone turned a broken iPod Touch into a wallet, and another person realized that an old shell phone makes a good modern piggy bank for kids.

4. Turn it Into a Security Camera

Instead of spending good money to buy a bunch of security cameras, why not just use old smartphones? They work brilliantly, and it's easy too.

There are two ways you can go about this:

  • You can use popular apps if your old phone is a smartphone.
  • You set things up manually so that the operating system doesn't matter.

For an Android-only setup, nothing is as easy as WardenCam. Download the app, place your phone where you want it, and you can watch all the action on another phone or computer.

In case you're looking to reuse non-smartphones with Wi-Fi, then you'll need to set it up manually. As long as it connects to your home Wi-Fi, we have the complete guide to set up old phones as a home security network.

5. Make a Universal Remote Control

This is one of the most popular ways to reuse an old smartphone. Whether it's running Android or iOS, you'll be able to control almost anything in your smart home.

You need to check whether your Android phone has an infrared (IR) blaster. This will let it connect to TVs, air conditioners, and other devices that normally use a remote control. Sadly, no iPhones have an IR blaster built-in.

If the phone has an IR blaster, just grab one of the best remote apps that we recommended.

If the phone doesn't have an IR blaster, you'll need to add IR connectivity. You can either add an IR blaster to the phone with a third-party accessory or you can buy the Logitech Harmony Hub. The Harmony Hub acts as an IR "base" for all your devices and then connects to your phone over Wi-Fi. If you have the cash, the Harmony Hub is the easiest option.

Related: How to Recycle Old PCs, Phones, and Other Tech

6. Create a Portable Gaming Device

Hopefully, your old phone is an Android with an expandable memory card slot or plenty of internal memory. If so, you can turn it into a portable gaming device for your kids (or yourself!).

This is perhaps the simplest way to repurpose an old smartphone, and your kids will love you for it. Given the amazing games released on Android and iOS these days, it's also a cheaper option than buying a PlayStation Portable or Nintendo DS.

7. Leave it In Your Car Permanently

repurpose-old-phone-car

A lot of people overlook the simplest use for an old smartphone. Grab a car phone holder, a double-port car charger, and fix your phone in place permanently.

It means you don't need to waste your regular phone's battery or data on GPS and turn-by-turn directions. That's what the car phone is for.

Similarly, you don't even need to spend a ridiculous amount of money for an awesome car stereo with Bluetooth and internet radio. Just buy one of the best Bluetooth speakers and play music from your car phone.

There are dozens of charities in both the US and Europe that will take your old phone off you, give it a spruce up, and then pass it on to people who can't access the latest tech quite so readily.

Some charities worth checking out include:

  • Cell Phones for Soldiers: To help people in the armed forces call their loved ones without charge.
  • 911 Cell Phone Bank: Provides phones to vulnerable people so they can call 911 easily.
  • Medic Mobile: Gives old phones to medical workers in developing countries so they can track diseases, register pregnancies, and communicate with other emergency workers.

Recycle Your Old Tech

Keeping hold of hold devices and finding new uses for them is better for the environment than chucking them in the bin. If you can't find a new home for the phone, find a new use instead. The same goes for other technology you have around the house.