Can you hack it? DIY goes digital

Never have our high streets or our living rooms hummed as loudly with the sound of gizmos and widgets. But for some this dizzying array is not enough. They are the geeks in garages who, brandishing screwdrivers, soldering irons and circuit boards, hack and modify things to create their own devices. A DIY hovercraft, anyone? Or how about a replica "hand repulsor gadget" inspired by Iron Man and made using parts from old hard drives and – of course – paper clips?

Heath Robinson-style tinkerers are not a new breed but thanks to the internet these solitary inventors have become a community. Their champion is Joe Langevin, an electronics graduate from Seattle who launched the website HacknMod.com two years ago. Langevin and his team of like-minded techies, who revel in their geekery ("there's a lot of pride in it," Langevin says), scour the internet for projects, or "hacks" and "mods" that would otherwise languish on obscure university websites. On HacknMod, which gets 10,000 visitors a day, the projects of hundreds of bedroom boffins are celebrated with pictures and videos.

Now the geeks also come to Langevin, who offers cash for projects that make the site. But why bother building, say, a DIY Segway, as one "modder" has done in the past week, when there's a company in America that does it pretty well? "Apart from saving money, it's about customising and making things that a million other people don't have," says Langevin, who would dismantle his grandfather's radio as an eight-year-old. "It's also a reaction to the iPod and the other homogeneous gadgets we all buy."

I do not own a soldering iron, but in the spirit of tinkering I agree to tackle a hack. Or a mod. Or something from Langevin's site. He suggests the "five minute, dirt cheap multitouch pad". It is, he says, a bit like the touchpads laptops use instead of a mouse, except that you can use multiple fingers. More like a bigger version of an iPhone screen, then, on which you can move your fingers together and apart to zoom in and out.

An iPod touch screen is about as hi-tech as it gets but the five-minute, dirt cheap version, which is the brainchild of a Californian student called Seth Sandler, requires only a cardboard box, some sticky tape, a bog-standard webcam, a picture frame, a piece of paper and a bit of free software. First I prepare the box by taping my webcam at the bottom so it points up and then thread the cable through a hole I make with scissors. Then, nicking a painting from my mum's wall, I replace the watercolour with a bit of white paper I tape to the glass. The frame simply rests on top of the box and there I have it – a cardboard box with a webcam in it and an opaque glass lid.

Then comes the hard part. I have to download the software and calibrate it. The touchpad will work thus: when you place fingertips on the glass they create shadows. The software, to which the webcam sends video of the underside of the glass, is designed to recognise and track these shadows, and replicate that movement on your computer screen. Applications that come with the software allow you to play a virtual piano or move photos around like they do in C.S.I.

It takes ages to adjust the settings and when I try the piano application I'm more monkey than maestro. It seems I haven't got the calibration quite right. The videos of Sandler demonstrating his own box on HacknMod are impressive but I lose patience with the whole thing – I'm not cut out to be a hacker or a modder. But for those who are given to geekery (or think they might be), Langevin's site offers a wealth of ideas ranging from the fiendishly complex to the idiot proof. Here are Langevin's five top projects...

How to make a dirt-cheap touch-screen

Do try this at home: The best hacks

Wi-Fi prank

We're constantly being told to increase security on our wireless networks so neighbours can't "piggyback" on the internet we're paying good money for. But what if, rather than block them out, we lured them in and played a harmless prank to teach them a lesson? This project, which should only be attempted by those who know their "DHCP server" from their "mac address", splits the network into two – one half is protected, the other is left open and is designed to flummox impostors. One scam directs all traffic to www.kittenwar.com , a site where photos of kittens can be rated, while another turns any internet page upside down or makes it blurry. http://tinyurl.com/56my6r

Emergency party button

The big red emergency button sitting on the coffee table in this project looks like it might detonate a bomb, but is, in fact, the ultimate way to get a party started. When the key is turned and the button pushed, the lights go out, motors whirl as the blinds are closed, a smoke machine is activated while 'What is Love', by Nineties dance sensation Haddaway, blares out of the stereo as strobes and lasers kick in with the chorus. The unnamed brain behind the button has spent more than £400 wiring up his house, and despite being the cheesiest mod on the site, it never fails to raise a smile. Should you be inspired, there is a step-by-step tutorial. http://tinyurl.com/6yg264

DIY free heating

Not all the projects on HacknMod are for people with degrees in electronics engineering. The key ingredient in this one is not a circuit board but drinks cans. They are emptied, drilled and connected into long pipes, which are laid in rows in a wooden chamber and painted black. The box is covered with glass or Perspex and placed outside and connected to your house via two pipes (in and out) and an extractor fan. The sun warms the air in the black cans, which is then cycled through your house. The budget DIY version linked at the bottom of the HacknMod page costs £40 yet warms the air that passes through it by an impressive 15 degrees. http://tinyurl.com/6abo4c

Laser surveillance system

Home modifications are some of the most popular but few can be as ingenious as this one, which recalls the laser beam scene in the Catherine Zeta-Jones film 'Entrapment'. Its key component is a laser pointer of the type ostentatious middle managers use on flipcharts. This is stuck to a wall in your house using Velcro. You then use Blu-Tack to stick small mirror squares around your house in such a way that the single laser beam is bounced across doorways or in front of valuables until it reaches a light detector Velcroed elsewhere. When an intruder breaks the beam a siren goes off. It can also be rigged to send you an email or text message. http://tinyurl.com/62xup4

Geek scooter

Sometimes hackers and modders get so carried away in their garages that they end up spending big money. This scooter must have costs hundreds of dollars because, using a router, GPS, touch screen and various antennas, it allows its rider to stream footage from a webcam to the internet, watch TV, go online, broadcast his own radio station, use GPS navigation and make Skype phone calls. It is, in the words of its makers, "the downright motherload of geek gadgetry packed into one scooter. You can also record TV programmes so you don't miss 'Lost' because you are lost". http://tinyurl.com/6j4s2o