CityGems

The idea

The Wave proved that a camera-free interactive installation survives real public use. CityGems takes that and spreads it across a city.

Gem-shaped modules clip onto lampposts, walls and fences that already exist. They react to movement with light and sound, and a companion app ties them together with maps, challenges and progress tracking. The target audience is 12–35 year-olds, and the point is to turn overlooked corners of a city into a social, gamified reason to walk, run and explore.

What makes it hard

You do not own the thing you are mounting to. A lamppost belongs to the city, carries its own cabling, and has to stay serviceable. Anything attached has to be non-invasive, safe, and acceptable to the people who maintain the street.

Every unit is somewhere inconvenient. One module on a bench is easy. Two hundred across a city means anything requiring a visit — a reset, a battery, a firmware update by cable — does not scale. Each module reports its own status so maintenance is driven by data rather than by patrol.

It has to read as intentional. A street is visually noisy: bikes, bins, signage, graffiti, greenery. An object that looks like utility hardware disappears into that clutter or reads as something to vandalise.

Each module is a compact weatherproof unit sized to a 40cm bounding cube, mounted 1–1.5m above ground.

From prototype to street test

Early enclosures went straight onto Rotterdam lampposts — not to test the electronics, but to see how the thing reads at street scale against real background clutter, and whether the mounting is honestly practical.

Physical shape tests worked out how the faceted gem form should catch light.

Concept placements along Schuttersveld were used to work out spacing, colour variety, and how the gems hold their own against graffiti and greenery.

The interaction itself was prototyped on the bench first, on a dedicated reaction panel, to get the timing and feedback right before committing any of it to an enclosure.

Built with THUAS

We prototyped the LED and sensor core with The Hague University of Applied Sciences, which gave students hands-on work building the interactive heart of the modules — and gave the project a second set of eyes on the electronics.

Where it stands

CityGems has been tested indoors at The Sun and informally on Teilingerstraat. Sportbedrijf Rotterdam has shown strong early interest, and Rotterdam’s city planners have affirmed the approach of mounting to existing infrastructure.

It is now moving toward pilot deployment.