Automation

 The use of automation on Shabbat is in principle a good idea in that no human actions are required at all. Everything is done automatically according to a plan set into motion before Shabbat starts. In fact, automation has become so linked in people's minds to Shabbat that a timer is often called a "Shabbat Clock" even if it is only used during the week for such routine jobs as controlling the lights in a store window.

 There are those who prohibit automatic operation on Shabbat. To our great benefit, this opinion has not been accepted in the halacha. Beit Shammai feel that there is a requirement that "equipment must rest," similar to the law with respect to work animals. This would mean that automation would also be prohibited. However, since the accepted halacha follows the opinion of Beit Hillel, there is no problem: The equipment can do as much work as including, including robots and automatons – as long as people continue to rest.

 Automation can help us on Shabbat not only by scheduling processes in advance (for example, turning lights on and off). We can also enjoy the benefits of automation when the action takes place at random times or on a regular cycle. This is the principle on which Shabbat elevators operate, going up and down without human intervention, either during a preset time slot or at specific intervals.

 There are times when a rabbinical decree limits the use of automation, mainly because of a fear of the suspicions of an observer. For this reason the Talmud prohibits allowing a water-powered flour mill to continue operating on Shabbat even if the wheat is prepared in advance and the mill grinds it "by itself." Similarly, playing music on Shabbat is forbidden even if the system is operated by a timer since somebody who hears the sound might suspect that Shabbat is being desecrated. Similarly, a passerby on the street who hears a washing machine inside a house might not realize that it is being run on a timer. Lights that go on and off during Shabbat are no longer included in the above suspicions, since it is widely known that timers are used for this function. Another action that is often permitted is irrigation, since it is very common nowadays for this to be done automatically. The same is true for air conditioning and other common equipment.

Applications:

•  Shabbat Timer – This is one of the most common devices in the religious home today, allowing the operation of various types of equipment to be scheduled in advance.
• Traffic Light for an Automatic Door – In places where an automatic door opens when a person passes close to a detector (for example, as protection against wind from the outside), a "traffic light" is installed for Shabbat observers. When Shabbat control is in effect, the detector is disconnected and instead the door is opened on a regular cycle for a short time every few minutes. One who wants to pass through can wait until the door is open, as signaled by the red-yellow-green traffic light.
• Dishwasher – In order to use the equipment on Shabbat, an automatic mechanism must be installed so that no human action will have any effect (for example, opening the door, putting in soap, etc). In order to do this correctly, it is important to follow certain conditions and to purchase a suitable model of dishwasher.
• Shabbat Elevator – The elevator works automatically according to a preset schedule without the riders having any influence on the operation. Many technical details must be taken into account to set this up properly, and therefore approval by an authoritative body is required to make sure that the elevator is indeed operating automatically according to all the requirements.
• Commercial Hot Water Urn – This is an automatic urn for large institutions, operating on an "overflow" principle. Water enters on a fixed cycle whether hot water is withdrawn or not. Any excess water automatically overflows to the waste.

For more information (in Hebrew):

• Rabbi Yitzchak Halevi Herzog, Operation of a Ship on Shabbat, Techumin 13.
• Rabbi Gideon Perl, Using a Dishwasher – Kashrut and Shabbat, Techumin 11.
• Rabbi Shlomo Levy, Using a Dishwasher on Shabbat and Holidays, Techumin 11.
• Rabbi Yechiel Faust, A Home Dishwasher – Operating it on a Shabbat Timer, Techumin 11.
• Rabbi Yisrael Rozen, Electric Generating Station – A Halachic Viewpoint, Techumin 16.
• Rabbi Prof. Zeev Lev, Using an Automatic Elevator on Shabbat, Techumin 5.
• Rabbi Yisrael Rozen, Automatic Elevators on Shabbat, Techumin 5.