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School of Electronic Engineering and Computer Science

Digital music platform offers new opportunities for disabled musicians

Strummi, a simplified guitar-like instrument made using digital platform Bela

Dr Andrew McPherson

Reader in Digital Media

A baton that allows visually impaired musicians to feel the movements of the conductor’s hands, a guitar that can be played with one hand – Queen Mary’s digital platform Bela opens doors for extraordinary innovations in developing new musical tools.

Dr Andrew McPherson and his team have developed Bela, an open-source hardware platform for creating digital music. Bela is easy to learn and use and offers superior technical performance.

As a result, thousands of artists, designers, students and researchers are using Bela to develop new ways of producing music and sound.

Technology that responds to musicians’ needs

Bela has ultra-low latency, which means that the delay between input and output is so quick as to be undetectable, solving a problem experienced with many digital instruments.

Musicians need digital instruments that are reliable, responsive and expressive, and which do not necessarily need to be tethered to a computer. They often want to be able to play and create in ways no designer could anticipate.

How can an interface be designed that embraces the user’s wilful subversion of its original goals? McPherson’s interdisciplinary research drew on human-computer interfaces, embedded hardware systems and arts practice to understand how musicians creatively (mis-)use technology.

From instrument to adaptable platform

The technical infrastructure, completed in 2014, was originally focused on a single digital musical instrument. The Queen Mary team expanded it over the next two years to become the platform they eventually branded 'Bela'.

The team collaborated with charities and other universities and developed new features, making it easier for people without an engineering background to create projects with Bela. At the end of 2015, Bela was in use by around 50 researchers and artists worldwide.

Bela launched on Kickstarter in 2016, where it exceeded its fundraising target, and thereafter spun out into the company Augmented Instruments Ltd in September 2016. There are now thousands of people using Bela.

Bela is low cost and you don’t need a master’s degree to build it. It opens up the opportunity to give access to music to people who didn’t have that before.
— Tim Yates, Research and Development Programme Leader and Associate Musician at Drake Music

How is Bela being used in the music world?

Bela in the marketplace

To date, Augmented Instruments Ltd (AIL) has sold several thousand Bela units, with sales growing year-on-year.

AIL has delivered technical consultancies to clients including a major European music technology company, a silicon valley entrepreneur, and start-ups in the UK, Israel and Finland. They have helped these companies to create proof-of-concept systems using Bela for applications, including audio processing, scientific data measurement and automotive systems.

Bela in the music community and industry

Thousands of unique users across six continents have bought their own Bela boards, and a similar number have encountered it through classes or workshops.

The Queen Mary team studied the characteristics of the Bela early-adopter community in 2017 and found a diversity of profiles and interests:

  • technology hobbyists and independent creators

  • musical performers

  • musical instrument designers

  • media artists

  • teachers

  • students

  • researchers in fields ranging from human-computer interaction to signal processing to neuroscience

Most of these users utilise Bela for musical applications, commonly building musical instruments and synthesisers. Dozens of instruments have been created by Bela users and are showcased on the project blog. Many also use Bela to create art installations.

Making music more accessible to the disabled community

The Accessible Music Hackathon

In February 2016, Bela was used in an Accessible Music Hackathon with Drake Music to develop prototypes of new accessible instruments.

Tim Yates, Research & Development Programme Leader & Associate Musician at Drake Music said, “We produce bespoke instruments for individuals; they have disabilities and can’t use standard musical instruments in the standard way, so we help them to use the instruments in a way that is specific to each person.” Two projects out of the 10 that were presented at the event used Bela.

The Haptic Baton

Visually impaired musicians are often unable to perform with an orchestra because they cannot follow a conductor. The Haptic Baton, created using Bela, uses motion sensors inside the baton to wirelessly transmit the movement data as vibrations to wearable wristbands. Musicians can thus feel the baton movements rather than following the visual cues of the conductor’s baton.


In 2018, Jacob Harrison and Robert Jack (McPherson’s PhD students) created Strummi, a simplified guitar-like instrument. Strummi uses Bela's low-latency audio processing so that the player experiences the richness of strumming real physical strings. However chord selection is managed using a series of buttons. This means the instrument can be played using just one hand.

Strummi, came out of a collaboration with the OHMI Trust, a charity devoted to music-making for physically disabled individuals. OHMI stands for 'one handed musical instruments'. Stephen Hetherington, founder of OHMI said: "By making the guitar fully playable with one hand, Strummi offers the real opportunity for many thousands of disabled people in the UK to play music for the first time."

The success of Strummi led to a £25,000 grant to Queen Mary from the Chelsea and Westminster Hospital Foundation to create a new instrument for stroke patients that could be used by patients at various stages of their rehabilitation.

Bela as an educational resource

Bela is being used in teaching in more than 20 universities in Europe, North America and Australia. It is a core part of the curriculum of a new cross-university Master’s in Music, Communication and Technology (University of Oslo, NTNU Trondheim).

The Bela team has also released a series of 22 free public YouTube videos on C++ audio programming with Bela.

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Schools, institutes and research centres

School of Electronic Engineering and Computer Science

With a 130-year history, our School offers a vibrant, multi-disciplinary learning and research environment. Our enthusiasm for research defines our programmes, keeping our teaching exciting and relevant.

Centre for Digital Music

We are a world-leading, multi-disciplinary research group in the field of music and audio technology. Since our founding members joined Queen Mary in 2001, the Centre has grown to become arguably the UK’s leading digital music research group.

Augmented Instruments Laboratory

We are part of the Centre for Digital Music (C4DM) at Queen Mary. Founded in 2011, the lab is led by Andrew McPherson and includes members and collaborators from across C4DM.

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