Airheads tweak virtual strings

PLAYING air guitar at work could land you in trouble, particularly if it gets ends up on YouTube, but it is part of the job for Richard Helmer a research engineer at CSIRO Textile and Fibre Technology near Geelong, in Victoria.

Dr Helmer looks like he is playing air guitar, including behind-the-head moves, but he is actually controlling a computer program that generates guitar sounds.

"Basically you have sensors on your elbows, you wiggle about and you can make instruments out of it," he says, making light of a serious endeavour. "It is not just guitars, but other stuff as well. In fact, the other night I started recording the first song using all air instruments. Look out."

Rehearsals to date have involved a four or five piece outfit that calls itself the Airheads.

Lyric lines include: "Wuh uh uh oh guitar hero ... let yourself go."

Helmer, who plays guitar and drums in an eight-piece band, was working with a team at the University of Wollongong on a smart knee-sleeve when he thought he could use a similar approach to make a virtual guitar.

The knee-sleeve project was a biofeedback device to monitor an athlete's knee to help them land correctly and prevent injury.

"The knee sleeve was a bit too techo for the market, so I decided we needed to do something that was a bit more market-friendly while people got used to the idea," Helmer says.

"I saw it and thought I could make guitar out of that, and in my own time I did.

"The first one was sort of clunky, with wires hanging off it and it needed four pieces of software.

"But in November 2005 I ended up with a German computing science student for six months and I gave him the specification to write and he put the software together.

"That got us to where we were last November when the website went up, and since then I have been improving the robustness, fleshing out some instruments.

"A lot of that was done at home, but now it is part of a bigger project to do body motion mapping and things like that.

"It has been a useful exercise to show that people are interested in this sort of stuff, and demonstrating that we can get a useful output from it.

Helmer says he has just finished a study with some secondary school students to assess whether they could learn it.

"We had a group of kids who were highly skilled - three years of guitar or four years with some other instrument - and those who had done a year of guitar and others who had no prior music experience.

"We looked at whether they could learn the song. That is the one on the web in the Yellow clip (www.csiro.au/science/ps29y.html - it is also on YouTube).

"They were able to do that in about six attempts. Obviously, the skilled kids were better at it, they learned it faster and were able to have a go at different skill levels.

"It pretty much does what it looks like, but we are looking at using it for other things, going back to sports, physio and assisted training - even medical applications such as seizure monitors.

"Part of the trust at the moment is massaging the whole system from the textiles to the software.

"You are trying to embed knowledge into the product, in this case musical knowledge - how the song is made and all that - so people who do not have musical knowledge can still do it.

"It is not just about the outcome: someone playing a song. It's getting technology into a form that is much more accessible - a bit like the iPod of guitars."

It's work in progress.

The unsightly wires of the prototype have been replaced with textile sensors embedded in the elbows of a long-sleeve T-shirt.

"With your fret arm you can probably do up to 10 positions. At the moment it is only six positions: 15 degrees, 30, 45 whatever. Each time you choose one of those you get a different sound.

"To make it simpler, you can have two arm positions: first and chorus, and the software will cycle through the chords.

"Once you are in Software Land you can do anything.

"We are starting with a simple set of signals from the body. You could play a song note by note on the bass guitar, but the average punter does not want to be fooling around.

"The first version I had finger positions and stuff like that, but it was ridiculous as you needed to be skilled to play it, which defeated the purpose."

The elbow movements are sent to a small wireless transmitter that clips on to the shirt with press-studs that make the connection.

That transmits to a little box that connects to a computer with a USB cable.

In the future, the box this is likely to be become a USB joystick.

"The whole premise is that you put it on, plug everything in and turn it on, open the software and choose a song and an instrument. Then you can play it with the actual sound of the recording."

The first commercial product from the system will most likely be interactive entertainment, Helmer says.

"Then there will be sports training - a bit of physio," he says.

"Then, once you go through all the clinical tests, you might get a few medical devices.

"In the more demanding applications such as medical, the accuracy and precision requirements go up."

Meanwhile, there is work to do, and not all of it involves Airheads rehearsals.

"It is pretty amazing. It is getting slowly more amazing as the days go by."