The (possible) absurdity of mapping human presence to six electrodes

It was established early on that the sensing system should be simple, robust and ‘forgiving’. ‘Forgiving’ in the sense that it should be able to accept false positives (of someone/something sitting) and gracefully realising the error. But more on that later. First, let’s talk about how we could detect people sitting on the park bench.

Briefly, the system works on capacitance sensing, a phenomenon that detects the trace amounts of electrical charge in our bodies that can be measured when we touch objects. For more details, please refer to the forthcoming article on this website that details more of the system behind the artwork.

3×2 sensing ‘grid’ to detect large general areas on the park bench

A three-by-two ‘grid’ system was conceptualised to map out the regions on a 1800mm park bench that can be discretely sensed as far as bodily presence is concerned. By quickly body-storming typical postures on a park bench, we asserted that the park bench should have distinct backrest and seat regions, split into the three sides that three people could comfortably sit on a single bench. From this sensing blueprint, we were then able to map out some other possible postures and user ‘stories’ that might unfold on the park bench.

General location of the sensing strips (highlighted in blue for clarity; they are to be concealed). Green dots on side are approximate locations of where the LED light strips will be installed.

These stories are indicative of the types of interactions that might happen – it is not our intention to force any of these ‘postures’ on the public. The interface of touch and optical light output is a relationship of experience derived from the act of sitting on the parkbench, and it is hoped that the public gets to discover perhaps curated or suggested ‘modes’ of usage which may or may not be the intended pattern to match the way the occupants are seated. This is something we wholeheartedly feel is ok. The resulting light animations are also suitably abstract for individuals to invoke their own interpretation of the gestures. In this context, one might say we got away without having to challenge the ambiguity of the interface, but even for such an open interface, details still need to be mapped out to get the prototype started.

This Coggle mindmap is our working conversation on nominating basic interactions intended for each park bench. We had an initial interest in creating park benches that communicate to each other about their occupancy.

We want people to encounter moments of discovery, that brings out a resonance to their emotions. A sparkly burst of light could mean a public expression of affection for two suitably lovestruck birds, but it could also signal to two friends a moment of wonder, or have kids enjoy a moment of surprise on an unfamiliarly responsive piece of street furniture.

The right choice of technology is made through trial and error. Never let anyone overtly serious about technology tell you otherwise. Best intentions and specifications sometimes do not work! We sometimes fall into the trappings of over-intellectualising how interactions should be designed. While the lessons gleaned from this deeper discussion on interaction affordances and signifiers offer a good starting point on how we might design interactive street furniture that has a certain degree of accessibility and creative ‘acceptability’.

Flowing particles…

Flows and movement upon, and in between cracks and gaps, were identified as a visual analogy to aid us in thinking about the lighting possibilities on the park bench. It seemed apt to consider the transient nature of park benches and the way flows emerge and subside. To that end, and in responding to the initial thoughts as drawn out in the user stories, the following types of ‘flowing’ particles were imagined:

  • CRACKS – breathing light that swells out from the cracks
  • MEANDERERS – light that traverses the length and span of the park bench
  • SPARKLES – bright, sparkling spots of light, not unlike a sparkler
  • TELEPATHIC – a similarly gentle breathing light that shows up when the other park bench wishes to tell us the first about it being sat upon

This video of a simulation software running off a derivative of the OpenPixelControl project demonstrates the early ideas of some of the above particles.

A pause for thought…

Some quick questions arose from this technological planning and working through the prototype. In determining the types of interactions that we would like to do, is technology choice the limitation, or part of the creative decision-making matrix? Is there always going to be some form of compromise or disappointment in discussing feasibility of a particular desired effect? Cost and effort, time and patience?

Also, in terms of the testing of the lighting effects, we realise that the interactant often is facing away from the bench, away from the lights, perhaps only in its periphery. It is the audience that sees, but not always attending to the light. On the other hand, the interactant becomes an actor; part of a performance. Who watches? Perhaps more on this in a separate post…

1 year ago

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