© Toby Williams
  © Toby Williams

Technology

NVA’s Head Designer James Johnson took on the challenge to illuminate athletes and walkers on Arthur’s Seat. Here he takes us through the development process:

The brief focused on four main areas of exploration: a lighting system that expresses the movement of running and walking; a lighting system that uses the minimum amount of power but gives the greatest possible effect; electrical power being generated or harvested by the runners and walkers movement efficiently and economically; kit that is rugged and simple to be used by a large number of runners and walkers on challenging terrain in all weathers.

Initial light research

Aesthetically the requirements of the runners and walkers kits varied greatly. The development of the runners’ kit was predominantly about the creation of something dramatic, whereas the walkers’ kit required a far more subtle approach.

Numerous investigations and trials were undertaken with different light sources (electroluminescent wire and tape, fibre optic fabric and diffused and non-diffused LEDs), helped by a team of specialists put together by the Edinburgh International Science Festival.

Also investigated was the comparative readability of point sources versus diffused light sources when viewed over distance and in varying weather conditions on the mountain.

Initial light research, runners and walkers

Rough prototype lighting arrangements were trialled on Arthur’s Seat. For the runners’ kit the concentrated point source of LEDs gave the best effect, both close up and at distance, and had the advantage of giving the ability to mix colour and adjust intensity.

For the walkers kit the subtler diffused lighting types, electroluminescent tape, fibreoptic fabric and diffused LEDs were found more suitable to create the desired visualeffect and also illuminate the pathways without glare. It was important that the audience/walkers night vision was not impaired for safety reasons and that glare did not detract from the viewing experience of the audience watching the runners.

From the research and development the design that emerged for the runners was a webbing suit that could be worn over their clothing, incorporating full colour LEDs, battery pack and radio control.

For the walkers/audience the chosen design was a static colour stick or baton that could be carried, the sticks creating a dramatic effect on the hillside in number but also illuminating the pathways for the individual walker.

Power Generation

Running parallel to the research into lighting types, investigations were carried out to see if it was possible to generate power or harvest energy from the movement of the runners and walkers with knee braces, pull string generators and piezo electric devices.

Although possible, the research demonstrated how efficient a runner’s motions are and how any interference or impedance in the motion dramatically affects the effort required and balance and coordination of the runner.

The more leisurely action of walking proved to be a better candidate for power generation and a series of walking staffs were developed that have the ability to power flashing LEDs. A smaller hand held baton that can be carried by the runners was also developed.

At the top of each walkers stick, (mentioned previously), is a removable polycarbonate tube that houses the flashing led assembly. The LED assembly consists of two led’s, two high power Neodymium Magnets and a copper coil. As the walker strides along the impact of the stick striking the ground forces one of the magnets to oscillate through the copper coil, the movement generates a small electrical current on the down and up stroke within the coil. The oscillating magnet is held sprung within the coil by a second magnet at the base of the tube that acts as a return spring. The alternating current is used to power the two led’s, one is powered from the electrical current created on the downward travel of the magnet through the coil and the other LED is power with the electrical current produced with the upwards travel of the magnet. The LED’s are held within a diffusing acrylic cap and the end result is a twinkling effect from the LED’s as the walker travels along.

Light Suit Tests

In summer of 2011 we commissioned 15 prototype light suits. The factors to be tested were:

- Was it possible to have one suit that would fit all runner sizes and how easy was it to get dressed and undressed? – Would the wireless DMX control system work on the terrain of Arthur’s Seat, allowing us to have individual lighting control over each suits colour and intensity? – Which components are likely to fail under the conditions of constant use and bad weather? – Two suit types had emerged through development: ‘stick man’ – an array of linear LEDs down the runners’ limbs and ‘node man’- point LED’s positioned at the joints. 10 versions of ‘stick man’ and 5 of ‘node man’ were constructed to see which one at distance would give the best aesthetic.

During the same test period prototype walking staffs were produced and the diffusing properties of various materials, frosted, dichroic film, light pipe and fritted material evaluated and tested by a group of keen walkers. The preferred option was a Light staff with a glowing acrylic rod mounted at
the base of a stick. The light is produced by a high efficiency LED run at less than 0.5 of a Watt internally illuminating the 300mm length of frosted acrylic . The light produced creates a puddle of light at the feet of the walker, giving the walker light to place their feet whilst not interfering with their night
vision. As the walker moves along the illuminated base of the walkers stick creates a pendulum motion. When seen on mass, a group of walkers take on the character of a many legged lolloping animal.

Further Developments

Following the original prototyping tests in August 2011, the ‘stick-man’ light suit was selected to be further prototyped, communicating over distance the shape of the human body better than ‘node-man’. Through four more prototype versions (including those destruction tested by Run Leaders Sandy and Leo) a final design was arrived upon and 120 lights were commissioned in time for our Super Sunday training events.

Throughout the technical rehearsals and performance nights of Speed of Light Edinburgh, the 120 light suits were worn by over 4000 runners. They weathered mud, wind and (happily) not too much rain, responding to lighting cues via an array of transmission equipment dotted across the site. The suits featured as key elements within the BBC Artworks documentary Running at the Speed of Light, an edit of which can be seen on The Space. In Yokohama, 50 suits were worn over the 2 nights, illuminating the runners during their 10 kilometre run. A film commissioned by the British Council will be available soon!