For Rifkie Silverman, the electric sliding door that Zachary Abraham and Daniel Bernstein built for their class project makes an ideal capstone for the engineering program she leads at the Frisch School in Paramus.

It’s not just that the two seniors from Teaneck designed the circuit and created the gears on the school’s new 3D printers, using design and programming skills they had learned in her engineering courses, which they took as freshmen and sophomores.

It’s also that the actual circuit design reflects a semester’s study of the intersection between technology and Jewish law.

“It allows them to integrate who they are with what they do,” Ms. Silverman said.

The sliding door is designed to solve a problem: How can observant Jews interact with an electrified world on Shabbat, when using electricity is prohibited?

Generally, observant Jews navigate this simply by not turning lights on or off, reading books rather than electronic devices, walking instead of driving to synagogue and back. But what about the sick? What about those who can get to synagogue only in a wheelchair?

And what about those who aren’t spending Shabbat at home and in the synagogue? How can you observe it when you are running a hospital or a military base?

Nearly 40 years ago, the Zomet Institute was formed to address these questions of halacha and technology. The Israeli institute’s vision “is to be able to merge scientific knowledge and Torah knowledge,” according to Rabbi Binyamin Zimmerman, a Zomet researcher and educator. It is “to be able to understand how God is interested in us applying Torah principles in the modern technological age.”

Zomet exists because the actual prohibition of electricity on Shabbat is not totally cut-and-dry. For a long time, halacha has distinguished between different levels of Shabbat prohibitions. There are some acts that are considered prohibited by the authority of the Torah, and there are others seen as banned only by the later rabbis of the Mishna and Talmud.

This makes a difference, because while Torah prohibitions must be set aside to save a life, lesser rabbinic prohibitions can be set aside for less urgent purposes.

“You have to balance the need versus what’s being given up halachically,” Rabbi Pinhas Weinberger said. Rabbi Weinberger is a faculty member at Frisch. Working with Rabbi Zimmerman and Ms. Silverman, he taught the first semester of the class in technology and halacha.

In the second semester, having mastered the halachic material, the students developed their projects, such as the sliding door.

Needless to say, the Talmud does not deal specifically with the case of someone being transported through a hospital and going past a door that opens with an electric eye. Multibed hospitals had not been invented yet, let alone electric eyes,

But there are a handful of cases that later scholars, particularly those 20th century ones considering questions about the use of electricity in their time, have found to be relevant for the principles they evoked.

Take, for example, the case of a rich man whose fortune is about go up in smoke as a fire approaches. The Talmud rules that he can put full barrels of water between the fire and his property. The flame will burst the barrels and extinguish the fire.

The person isn’t directly putting out the fire, which would be forbidden on Shabbat. But he is causing it to be extinguished.

14-2-L-sliding-door-2That principle of indirect action — “gramma,” in the Talmud’s Aramaic — underlies the products that the Zomet Institute designs. Using variations of the gramma principle, you can steer an electric wheelchair, turn on an electric baby monitor, and even type on a computer keyboard.

That is, if your need is great enough.

And like most matters talmudic, the question of how great a need is the stuff of argument and debate (which is why Rabbi Weinberger could spend a semester teaching this material).

But according to Zomet’s website, according to some rabbis the anxiety of parents accustomed to using a baby monitor six days a week is sufficient to let them use a monitor modified with the gramma principle on Shabbat.

Once they finished the halachic course and began brainstorming their project, it didn’t take Daniel and Zachary long to settle on an electric door.

“We were thinking of something maybe in a hospital,” Daniel said and soon hit on the idea of making the electronic doors more Shabbat friendly.

“We tried to minimize all the potential halachic violations in the system,” Zachary said. “We built a system where all the components were, in theory, not violating certain aspects of electricity on Shabbat.”

This is where their understanding of the technical details of Jewish law meshed with their knowledge of the technical aspects of engineering.

“One of the main issues with using electricity on Shabbat is making and breaking a circuit,” Zachary said. “Creating something is not allowed on Shabbat.”

So their door doesn’t use a regular direct current motor.

Instead, it uses something called a stepper motor, which, Zachary explained, “always has electricity moving through it. It never actually breaks the circuit.”

Similarly, rather than using a standard electric eye, which turns on or off when it senses someone coming through, Zachary and Daniel’s device uses a sensor that continually reports whether or not someone is there — with a change in voltage indicating whether or not to open the door. The voltage changes but it never stops, and the circuit is never broken.

The final piece of the door’s not-on-Shabbat twist has to do with its coming to a rest. An ordinary electric door would, well, notice that it’s all the way opened (or closed) and stop. But that would be closing the circuit.

Instead, the gear that moves the door continues to push on the door, albeit it very lightly, even when it is in place. It’s not stopped by turning off; it’s stopped by the pressure of the wall where it has come to rest.

“We adopted that idea from an article from the Zomet Institute,” Zachary said.

On the practical engineering and construction side, “all these different skills we learned in engineering class came together,” he said.

“It was a fun project to work on,” Daniel said. “It gave us an opportunity to work on something we’re passionate about, an opportunity to combine some of the Judaic aspects and more secular aspects of what we learn in Frisch.”

All of this is music to Ms. Silverman’s ears.

“I want out students to see that technology and halacha are not really two disciplines,” she said. “We’ve been given the ability to develop computers and technology, yet we are also given a set of laws by which we’re supposed to live our lives.”