Keeping your home safe is important to everyone, but using your PC isn't necessarily the first thing you'll think of when it comes to home security.

However, it can be a very useful tool in letting you keep abreast of what's been going on and, with an internet connection costing about the same as the monthly fees for a monitored burglar alarm, why not save money and keep an eye on things yourself, or let the computer do it for you?

Many people have a webcam on their computer, and there's plenty of software that will spot when things have changed, and save a picture. But it hasn't been top of the list when it comes to making your home secure.

The situation is changing now, as many people have broadband connections that are always on. That makes it more feasible to use a PC for security, without worrying about tying up phone lines, or the time taken to update a picture on a remote web server.

Depending on the details of your net connection, it also means it may be possible to connect to your computer from elsewhere, and see what's happening in your home.

In fact, the internet is slowly edging into the security market in various ways - we'll look at some of them here - but there are other methods. You could, for instance, use a remote control application like virtual network computing to connect to your PC and view webcam pictures.

Home monitoring
Burglar alarms that have a monitoring facility have been around for years, and often involve fairly expensive response centres, staffed by people who try to contact you when the alarm goes off and alert the authorities when necessary.

It's no surprise that the internet and mobile phones are being used to try and cut down on the number of people needed to provide such services, so that they can be made more affordable. One such system is BT's home monitoring service, the Home Monitor VP1000 (www.bt.com/homemonitoring), which is based on a DIY installable alarm, similar to the cordless systems you can buy at most DIY warehouses.

At £250 for a control unit, one door or window contact, two motion sensors, a dummy alarm box and a keychain remote, it doesn't look like great value, but it has some tricks up its sleeve. Besides making a lot of noise when the alarm goes off, the control unit plugs into the phone line.

As part of the installation, you create an account on the BT Home Monitoring website; you can specify up to three contacts with mobile phone numbers, email addresses or ordinary phone numbers. When an alarm is triggered, the system calls your home, then alerts the contacts if the alarm hasn't been reset.

You can also sign in to the web page from anywhere and check to see the status, including whether batteries in sensors need replacing, or which sensors have been triggered.

Many people may choose to add other detectors, such as a smoke alarm or extra door contacts, putting up the price - and after the first three months, you'll have to pay an additional £5 per month for the monitoring service.

Nevertheless, for those who would like a little extra peace of mind without the expense of a typical call-centre-based system, it may be worth looking at. Just remember that the only people who'll be alerted are the ones on your contact list; BT's system won't call the emergency services for you.

BT's system, clever though it is, probably doesn't make quite enough use of the internet to satisfy the hard core technophile. Who's going to be satisfied just knowing that something's happening at home when there's technology out there that will let you see every detail?

Network webcams
Webcams are the obvious way of keeping an eye on what's going on at home, and with broadband connections it's simple to set up a window on your living room using one of the many camera-sharing websites.

If you have a web page of your own, you can always arrange for pictures to be uploaded there every few minutes, and many webcams come with software that can be used to detect motion. However, much of this software is pretty basic; it will simply compare images to see if there's been much of a change since the last shot, and then save the image, or start to record a video stream if it spots motion.

That might sound like all you need, but such simple motion detection has its drawbacks, as you'll find out on a windy day when you come home to a hard drive filled with pictures of gently billowing net curtains.

To avoid this problem, choose a camera position carefully, or pick software that can be programmed to avoid small changes in the scene.

Alternatively, you can use a passive infrared motion detector like the ones used in burglar alarms; modern ones are even clever enough to avoid being triggered by small animals.

There are other solutions if you can access your network remotely. Veo Products has a range of cameras that connect directly to a network, either via an ordinary wired connection or via 802.11b wireless. They have built-in web servers, so you can connect to them over the internet and see what's happening, and even listen to it.

While the cameras themselves can be bought for around £120, a motion sensor is an optional extra, and you'll want to add one if avoiding the net curtain problem is important to you. For around £150 you can have the wireless version, which will ensure you can add security to your home without running cables everywhere.

Since you have to connect to these cameras from outside, rather than letting them upload pictures to a web server as you would with a typical webcam, you may have problems with some types of domestic broadband connection.

That's because many of these are not designed to run servers, which is essentially what these cameras are; they rely on a Java or ActiveX applet downloaded to a web browser which can be used to view the images.

If a firewall or service restrictions prevent you from connecting to your computer, you won't be able to use this type of camera. Some types of broadband may allow you to connect but, if you have multiple cameras, you might need to do some complicated configuration of routers or firewalls.

Beyond a single camera
There are some situations in which a single camera may be all you need - if there really is only one way in and out of your home, for example - but in many cases, that's not enough. And that's where things start to become more complicated for the PC home security enthusiast, not to mention more expensive.

Observation cameras that you can connect to over the network, or better still a wireless Lan such as the Veo Observer, may be a great idea. But when each one costs £120, fitting one at the front and back of your home, one indoors, and one covering the garage, for example, is going to be pretty expensive. This sort of system is best suited to businesses that can more easily justify the expense.

If you already have a conventional monitoring system with cameras that produce Pal video output then you don't even have to rip those out; instead you can add a video server, such as the ones from Axis Communications, which can connect either a single camera or four at a time to the web.

If you want to capture images, the company also produces digital video recorders so you can record clips and then access them over the web later.

More interestingly, Axis also produces its own network cameras, which are based on an embedded version of Linux and even offer the possibility of panning or zooming the camera via remote control over the web. But this costs around £300 for a camera, and considerably more for the video servers to use with existing CCTV systems. In other words, definitely a business product.

But that doesn't mean home users should be denied the opportunity of multiple-camera systems to keep an eye on what's going on at home. Step forward the Incontrol Quadcam system (from www.digital-cybermasters.co.uk), which provides up to four cameras and a controller box that links them together and combines them into a single USB input for your PC.