The Laser Eruv

An eruv is a symbolic boundary – a wire – that is suspended around orthodox Jewish communities throughout the world. It is typically strung between utility poles above the city streets, a somewhat fragile arrangement prone to storm damage and requiring laborious upkeep.

The laser eruv, in contrast, creates a boundary out of continuous beams of light. Obstructions like the branch of a tree will interrupt the flow of light without damaging the apparatus. As such, it represents the most significant advancement in eruv technology since the telephone pole.

The eruv (pronounced ay-roov) is an ancient architectural construct rooted in the observation of the Sabbath, the weekly day of rest that includes a prohibition against carrying objects (even house keys) outside the home. The eruv mitigates the impact of this restriction by symbolically converting the public space within its boundaries into the shared private space of the Jewish community. In this way, observant Jews within the eruv can carry objects outside of their homes without violating the Sabbath.

Because a breach in any portion of the eruv renders it useless, a manual inspection of the perimeter is conducted prior to every Sabbath. This is not necessary with the laser eruv. Each laser is shot directly into the lens of a small surveillance camera across the street, creating images like the one above, a so-called bloom of laser light. If a beam is interrupted, the surveillance camera will register the absence of its bloom, easily pinpointing the portion requiring maintenance. These images can be broadcast on the web and examined by individuals using their own computers, before the setting sun prohibits the use of such devices.

More about the eruv:
Eruv Storm Damage in The New York Times
Jewish Ideas Daily
The New York City Eruv Code
Eruvim in Modern Metropolitan Areas
Talmudic Places in a Postmodern World
Between City and Desert

Related work:
How to Zap a Camera Notes on Social Architectures as Art Forms
On Drawing Lines on a Map
Sophie Calle

Thanks to David Neff for engineering and photography.