Every now and then we stumble on a shed-based boffin who is making some exceptional instruments, and we just have to make a glitchy song-and-dance about it. Meet the crazy inventions of Dave Cranmer

As soon as we saw these instruments we had to track down the brains behind the boxes. A rack of eight Furbies lashed into an hand-cranked box called the Furby Gurdy? We had to know more about this and the rest of his creations.

Luckily the eccentric bending-guru was willing to give us an insight into his instruments and projects. We put on our home-made colander/ideas helmet and fired away.

FM: Tell us about yourself and how you began making these cool devices!

My name is Dave, I am 26 and live in East London in a house with a small shed. I'd always been interested in electronic sounds and music, but the thing that really started the home made stuff was a demonstration by Paul and Emma of Lektrolab.com.

Paul had a battery powered doorbell that played different melodies, and after opening it up he simply placed a finger over a resistor to change the pitch of the sounds being produced. It was a really exciting moment - I had always presumed that working on something like that would involve having an incredibly detailed knowledge of the entire circuit board.

I thought that you would have to know all of the precise component values, and if anything was slightly changed then there would be a pop and a wisp of smoke and that would be the end of that.

This demonstration instantly showed that you could just use trial and error until you heard something that you liked, and that the circuitry had a high tolerance to being poked around with.

FM: How would someone start if they were interested in getting into Circuit Bending?

Every week hundreds of eBay-compatible mums sell the musical toys that their babies have outgrown, and these make ideal cheap circuit bending projects.

Any battery powered toy that produces some kind of electronic speech, sound effect or melody is ideal. Slightly older toys tend to be easier to work on, as their components are usually larger and more accessible.

A few basic tools such as a soldering iron, set of screwdrivers, wire strippers and pliers, and you're ready to use Baby's First Radio to conjure the voice of Satan.

Cheap toys are excellent to start with, as you can use them to get a feel for the process of circuit bending without damaging any expensive audio gear. There is plenty of advice on the internet on how to get started, although I think learning the techniques behind how to find your own modifications is better than simply following step-by-step guides.

FM: What has been the most complicated project and why?

So far it has been the first Furby Gurdy, just because it has involved a lot of different processes, such as making the case, hand filing the cams, wiring up the furbies etc.

FM: How much does it cost for one of these devices?

Hmm, it depends really on the amount of work involved, the number of units produced, and the materials used. The 'voice changer' effects boxes are about 80, but then a custom commissioned device, depending on what goes into it, maybe starts around 500.

Some people ask if they can have a lower budget device with a cheaper finish, and some people want extra diamonds, so that all effects the final price of the unit.

FM: You've had some famous customers, tell us who and about how it happened...

I think my favourite was getting an e-mail out of the blue from Adrian Utley, after being a Portishead fan for a very long time. He bought a modified 'My First Talking Computer'. I haven't heard the new album yet, but I hope it hasn't replaced Beth's vocals.

FM: Do you make music using these devices? Where can we hear it?

I've done a couple of small live shows recently, and should hopefully be playing at the Sonic Arts Expo in Brighton this year. New Cross based band Naked With Horses also let me practice with them from time to time.

FM: What are you working on next? How do you come up with new ideas? Do you take commissions?

New ideas tend to arrive at a fairly constant rate - the problem really is prioritising which project to finish first and trying not to get distracted by starting too many new ones.

Discovering new tools, materials and components also inspire new ideas - tool catalogs are great for this! I have nearly finished two musical stepladders, which should be making an appearance at the Sonic Arts Network gig. They each have lo-fi sampling capabilities, enabling the user to record a sound for each tread. Each of the treads is mounted on springs, and plays back a sound as you walk on it.

I have also very nearly finished four new smaller Furby Gurdies, which will be for sale in May/June.

There's also a couple of commissions on the go, but I am always happy to talk about more!

(June 2008)