Urban environments are increasingly filled with digital display systems that are inflexible, flat, bounded, high-resolution, and unresponsive. In this paper, we explore the potential of physically instantiated pixels that enable flexible, reconfigurable, unbounded, low-resolution, and responsive urban displays. Urban Pixels are nodes in a wireless network of physical pixels for urban spaces. Each pixel unit includes a microcontroller, RF transceiver (433 MHz), LED module (ten bright, white LEDs), rechargeable Li-Ion battery pack, IR sensor and renewable energy source such as photo-voltaic cells. Two acrylic half-spheres (4-inch diameter) protect the components from the elements. No additional wiring is needed for communication and the units can be mounted individually to any surface. A small-scale prototype network of fifty Urban Pixels was displayed on a façade of Eden Court Theater in Inverness, Scotland from June 1 - June 7, 2008. The public was encouraged to change display patterns via SMS or to interact with individual units via flashlights. We observed and informally interviewed theater guests and passers-by interacting with the façade for several nights. Based on these results, we outline an exciting problem space for designing displays and lighting systems in cities.

William J. Mitchell is Professor of Architecture and Media Arts and Sciences and Head of the Media Arts and Sciences Program at MIT, in Cambridge, Massachusetts.He holds degrees from the University of Melbourne, Yale, and Cambridge. He is a licensed architect, a Fellow of the Royal Australian Institute of Architects, and a Fellow of the American Academy of Arts and Sciences. Before coming to MIT, where he served as dean of the School of Architecture and Planning from 1992 to 2003, he held faculty positions at UCLA, Cambridge, and Harvard. He has also held numerous visiting academic positions, including that of Thomas Jefferson Professor at the University of Virginia. At MIT he serves as Architectural Advisor to the President of MIT, and has played a major role in the current large-scale rebuilding of the MIT campus. He chairs the MIT Press Editorial Board, is a member of the Management Board of the MIT Press, and serves as a trustee of Wellesley College.He is the author of thirteen books on architecture and urban design, information and media technology, and the visual arts. These include The Logic of Architecture, The Reconfigured Eye, City of Bits: Space, Place, and the Infobahn (MIT Press, 1996), and E-topia: 'Urban Life, Jim - But Not As We Know It' (MIT Press, 2000). The latest, published by the MIT Press in October 2003, is Me++: The Cyborg Self and the Networked City. In 2002/2003 he chaired the National Academies panel that produced the report Beyond Productivity: Information Technology, Innovation, and Creativity (Washington DC, National Academies Press, 2003).

The LT-1 connector has been designed to provide an economical means of terminating analog transmission facilities on the No. 4ESS, a digital toll switching machine. It performs a bilateral conversion between two 12-channel analog group signals in the 60-108-kHz band and a 24-channel digital digroup at 1.544 Mbits/s. In addition, signaling information in the form of a 2600-Hz tone must be converted to the digital format. The connector has been implemented with conventional per-circuit technology but achieves significant savings compared to back-to-back channel banks. This is accomplished by eliminating redundant circuitry and using a number of custom designed silicon integrated circuits. This paper gives a description of the design and some typical performance data.