If you're anything like me, you probably have more than one old smartphone hanging around in draws and boxes, just gathering dust. I think I've got three, from an old (and very reliable) HTC Desire to a Sony Z3 that doesn't work as a phone (my wife dropped it), but does have a perfectly operable camera and screen.
Have a look in your bedside cabinet - are you the same? Got a bunch of phones doing nothing?
Well, a few weeks ago I was reading an article that was talking about security, and there was an assertion that security agencies such as GCHQ and the NSA could hack into phones and switch the camera on. The article was clear - if you have a mobile phone, it's not secure, and somebody could get to it.
If they can do it, it means bad guys can do it. They can see what's going on in your home simply by hacking into the camera and viewing it!
Now, I've looked into this in some detail, and it seems the encryption in the latest versions of Android and Apple OiS are pretty good, and you're not likely to be hacked anytime soon. So you don't have to store your phone in a lead lined box when you go to bed. Rest easy.
But, it got me thinking. If it's possible to do this, then surely it must be possible to view the camera remotely if done legitimately, i.e. with an app.
Turns out there is!
Let's cover the big question first, why would you want to do this?
The first obvious reason is security.
When you're out of the house, and a burglar decides he wants to run off with your telly, it's good to be able to see it happening, it's even better if you can get an alert when it happens so you can call the cops.
And, if you've got a recording of the deed in motion, you have some evidence to use to catch the thief if the police don't get there in time.
There are other reasons, though.
Want to keep an eye on your child as he sleeps in his cot? Want to make sure the kids in the playroom aren't getting up to anything dangerous? Want an eye on the garden to see if a badger is digging holes?
These and many more ad-hoc reasons are enough to make it worthwhile digging out your old tech and making some use of it.
First off, you'll need an app. There are many around, but I used "Presence" which is available from the Google Play store and is free.
Grab your old phone, the one you're going to use as a camera, and download the Presence app. Load it up and you'll be asked to register an account - remember your password.
When it's all set up, you can start the camera.
What you then get is a bunch of options that allow you to fine-tune how the camera will be used.
For example, you might want to record any motion that's sensed. So, if you position the camera on a shelf, it'll happily sit there waiting for something to move. When it does, it will record this for a set amount of time and store it.
This is especially useful for wildlife recording. Set it up pointing at the garden, and when that badger turns up - it'll record it. But it can also be used for security.
If the room should be empty, and someone walks in, then it will start recording.
There are also options for recording sound, broadcasting to Twitter (haven't tried that, seems a little odd) and setting the sensitivity.
Once you're all set up, you can view your camera from either another phone using an iPhone or the same Android app, or connect to it via the web, where you can see a live stream.
It's only fair to make it clear that this is far from an ideal security camera replacement. I'm using a particularly good phone with an excellent camera, but the quality leaves a lot to be desired.
Although you could probably make out the person's face, if your camera was a distance from them, you'd have trouble seeing any distinct features.
Also, there's a lag on the display. What you see on the web or via the phone app is a few seconds behind real life.
And of course, there's the battery thing.
Cameras on phones tend to suck battery power, so you'll need to have your phone plugged into the mains in order to use it for extended periods.
There are a number of apps that will do a very similar job to Presence, but you have to bear in mind that they will all suffer the same flaws.
For the gadget freak who wants to make the most out of their old tech, then this is a great thing to tinker with, and it's certainly a lot of fun. If you have multiple cameras, you can set them up all around the house and create a rudimentary security system.
With a bit more imagination, I'm sure you could create boxes for them, hide the power cables and get quite sophisticated, but overall, they're not going to replace a real security camera that is dedicated to the job.