JERUSALEM -- Electrical wire and circuit boards clutter the cramped office of Rabbi Levi Yitzhak Halperin as he scours ancient Scripture for ways of making technological advances compatible with a devout Jewish lifestyle.


Halperin's Institute for Science and Halacha -- Hebrew for Jewish law -- helps Orthodox Jews deal with aspects of modern life ranging from skyscrapers to an Israeli army that works on the Sabbath.


Its one-story building in a residential neighborhood bustles, murmurs of prayers mixing with the sound of a drill boring a circuit board. Bearded Bible scholars in the black garb and sidelocks of the ultra-Orthodox debate physics, theology and engineering in dim corridors.


The result is dozens of inventions designed to reconcile the mundane devices of modernity that clash with Halacha.


Among them are a telephone and an elevator that may be used on the Sabbath -- sundown Friday to dusk Saturday -- by Jews who believe that activating electricity amounts to doing work, which is forbidden on the day of rest.


"Our Torah was given 3,500 years ago. Today the light is the same light, but the means of producing it have changed,'' said Halperin, 61. "We must deal with these developments and explain them according to the ways of the Torah.''


Halperin's elevator is preprogrammed to stop at every floor on the Sabbath and is used in hospitals, hotels and high-rise apartment buildings. Thus, the people who ride the elevators do not have to push any buttons, considered doing work under Jewish law.


The telephone uses a steel pen to interrupt beams of light aimed at photostatic cells, which sets off dialing. A similar system activates the heating mechanism of a hospital food cart.


Halperin's adviser, Shimon Stern, argues that this complies with Sabbath laws by merely interrupting an existing electrical signal as opposed to causing one and thus breaking a Jewish law against creating electricity on the Sabbath.


"There's no direct connection between the act and the result,'' Stern said. "Electricity is suspended ... you caused it but didn't actually do it.''


The institute's explanation for equipment that seemingly bends the spirit if not the letter of Sabbath law is that the devices are intended for use in hospitals or by the army when lives are in danger.


Halperin said the inventions are meant to help observant doctors keep Jewish law even on the Sabbath.


"There were lots of things that were problems where a man had to hesitate about what to do. These were solved with technology,'' said Halperin, who founded the institute 30 years ago.


One of the institute's devices, a pen filled with an ink that disappears in several days, is less clear-cut.


The Torah, Judaism's holy book, views writing only as something that is permanent. Some rabbinical scholars who interpreted the law over the generations held that any kind of writing was forbidden on the Sabbath.


Stern says disappearing ink could be restored with a hot iron, giving it permanency and therefore should not be used on the Sabbath. But doctors and soldiers may need to write on the Sabbath and using a disappearing ink pen would make their transgression less grave, he argues.


While leaders in the ultra-Orthodox community praise Halperin's efforts, some modern Orthodox Jews say the institute's equipment could create an obsession about the form rather the substance of religion.


"These are very fine hairbreadth issues that seem to be dealing with minutiae but nevertheless are an important function in finding the balance between the letter and the spirit,'' said Rabbi David Rosen, former chief rabbi of Ireland.