While it might lag playing Candy Crush, an older smartphone is still a tiny, powerful computer that can be useful in many ways. Better yet, the projects we’ve collected here generally won’t cost you a thing.
Android is a particularly flexible platform for phone-repurposing, but many apps also have iOS and Windows Phone equivalents.
IP security camera
An IP Camera can be used for tasks from monitoring the dog while at work, to being part of a bigger motion sensing security system.
The key to getting started is an Android or iPhone app called IP Webcam. This lets you remotely access the camera over the network or Internet. You can also use the microphone, speaker and LED flash.
Other free and paid apps can motion activate, record video and sent alerts. Get a cheap car mount for the phone to help get the right viewpoint, and make sure it’s plugged and charging.
Car or bike computer
Instead of buying an expensive GPS speedo, an app such as GPS Speedometer turns that spare phone into a powerful measurement system. Get an accurate speed, check your elevation, record trip distances and time, and get limit warnings.
By downloading offline Google maps on Wi-Fi, a smartphone can also be used as a dedicated GPS unit.
For car use, an app such as Torque can turn a smartphone into a dedicated car computer. Linking with a Bluetooth OBII reader, you can monitor your car engine, check fold codes, watch sensor data and set alarms for issues such as overheating.
The app can also measure acceleration and record info from track racing.
For Android users with a Chromecast, most major apps such as Netflix and YouTube can be simple to cast to a TV.
A smartphone with inbuilt IR blaster can control devices from TVs to air-conditioners directly, using the AnyMote app.
G-mote (or iTunes Remote) can be used to control a PC or Mac directly, from music and movies to operating as a Wi-Fi touchpad and keyboard.
GPS tracking bug
Dreams of becoming a PI aside, GPS tracking is probably better suited to your own vehicles, instead of an expensive security system. Combined with a cheap pre-paid sim-card, a smartphone can be used to remotely check the location of a stolen car or boat.
Newer iOS and Android phone can be tracked through an account, but apps such as Glympse give a greater range of options such as logging or movement alerts.
With a car charger, a phone can be hardwired in a hidden location and won’t ever run out of power. Otherwise, coupling a phone to a high capacity power bank and putting it in a sealed container gives a bug that can operate for up to many weeks away from the charger.
Add wireless charging to (almost) any phone
Potentially one of the most handy, yet often overlooked features of a smartphone — wireless charging — is fairly easy to retrofit. Both receivers and charging pads are super affordable, and, together, can cost under $20.
Having to plug in a cable each night might not seem like much of a chore, but wireless charging is more about always being topped up. The chargers are so cheap that it’s easy to have one next to the bed, in the car, on your desk at work or in the living room.
Plopping your phone down on a pad, rather than just a table, means it will almost always be fully charged throughout the day.
Many phones (such as some Samsung’s, the LG G4 and more) actually have provisions for wireless charging to be added. It’s as simple as finding the right receiver — eBay has a huge selection.
From there, it’s as easy as popping off the back cover, sticking the receiver in place and putting it all back together. This is the ideal way to add wireless charging, as it means the USB port can still be used as normal.
Not many phones have this option, but always check to make sure.
Universal charging receivers
For other devices without an upgrade option, you need to get a little more creative. Fortunately, it’s possible to buy a variety of receivers that can be fitted to almost any phone.
The catch is that, for many phones, you either have an ugly pad stuck on the back, or need to cover it all up with a case. USB Type-C users are out of luck, at least for now.
For some phones (such as the iPhone), it’s also possible to buy cases that have QI charging built in.
The universal charging receivers come in a range of different types, and it’s critical to get the right one for your specific device.
iPhone users have it easy — since all the phones are very similar, it’s as simple as searching for an iPhone compatible model. Android (and to a lesser extent, Windows Phone) users on the other hand have a large array of options.
The problem is the location and orientation of the Micro USB port. Depending on the model, it can be on the side (high or low), on the bottom, or offset from the middle.
The port can also be orientated in either direction. Fortunately, there are a huge range of receivers available to suit most phones.
The receiver simply plugs into the phone’s charging port, then is curled around to lie flat against the back panel. Then the unit is carefully put into a case to hold it all in place.
In our testing, the charging works through even thick wallet style cases, but can be blocked by metal.
With some phones with a removable back cover, it can be possible to tuck the receiver pad inside, leaving just a thin ribbon cable out to the charging port.
Wireless charging is not just limited to a phone — it’s possible to add to all sorts of devices. Tablets, eBook readers, cameras, power banks, Bluetooth speakers and more can all benefit, just make sure you pick a suitable receiver module to match.
Another excellent use is that old phone being used as a remote. Keep a charging pad by the TV and the remote has a home that keeps it always topped up.