A front page article in The Times on Friday describes widespread winter storm damage to eruvim across the northeastern United States. For those unfamiliar, an eruv is a symbolic boundary – a wire – that is strung between utility poles around the perimeter of an orthodox Jewish neighborhood.

In 2006 I created the laser eruv, a wireless boundary not susceptible to the kind of damage described in the article:

The eruv that circumscribes a large chunk of Manhattan from river to river between Harlem and the Lower East Side was damaged in 18 places last week by the combination of wet snow, high winds and falling branches.

Until it is repaired, observant Jews inside the eruv cannot carry objects outside of their homes on the Sabbath. Carrying anything outside, even house keys, is considered work, a violation of the sacred day of rest. The eruv gets around this restriction by converting the space within its boundaries into the shared private space of the community, essentially expanding the definition of home where some carrying is allowed.

To ensure its function, the entire perimeter of an eruv is inspected 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 registers the absence of its bloom, easily pinpointing the portion requiring maintenance. These images can be broadcast to a monitoring facility or out on the web and examined before the setting sun prohibits the use of electronic devices.

For more on the eruv, see my previous work A Street History in Semacode.

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.