Several organizations specialize in halakha and technology, devoting themselves to engineering electrical appliances to turn on via grama so that they may be used in cases of need. One such method is called “removing an impediment” (hasarat ha-mone’a). A second method uses a type of scanner that performs a scan every few seconds and turns an appliance on if it determines that a switch has been flipped. Thus, flipping the switch does not turn on the appliance but only causes it to be turned on indirectly. A third method is based on the principle that one may extend the present state: the appliance is set to turn on for one second every few seconds. When the switch is flipped, the next time the appliance turns on, it will not turn off after a second but will remain activated.
Others maintain that one may not use any of these clever stratagems. If an appliance is set to be activated electronically, causing its activation is not considered grama but the normal way of activating it.
In practice, it would seem that if one’s action causes an appliance to turn on within a short time, like it would be turned on during the week, then even if the appliance has been programmed to turn on in a grama-like way, one may not turn it on. The internal workings of the machine are not important; if it turns on in a way that looks normal, then that is not considered grama. Therefore, elevators and automatic doors may not be turned on via grama; since the goal is for them to function in their normal way soon after being turned on, it would not be considered grama. Similarly, one may not travel using a “kalno’it” (an electrical wheelchair or gold cart specially designed for use by the sick, disabled, and elderly on Shabbat), since it operates in the way that one would operate a similar device during the week.
In contrast, when one’s action causes an appliance to turn on only with a significant delay, then if it is brought about indirectly – whether by hasarat ha-mone’a, scanning, or extending the present state – it is considered grama, and such a system may be used when needed. This is the practice regarding arming a security system: if turning a key will cause the system to work via grama, and it will only actually arm itself ten minutes after the key is turned, it is considered grama, and one may do so in cases of great need.
. R. Levi Yitzĥak Halperin, the head of the Institute for Science and Halakha, maintains that in case of need, one may activate devices by “impeding an impediment.” For example, consider a device that is in working order, but a beam of light hitting a particular spot prevents the device from working. When one blocks the light beam, the device begins to work again. Thus, blocking the beam “impedes an impediment” and is considered a grama. According to R. Halperin, technically this is even less severe than grama, but many disagree with him.The Zomet Institute has developed three strategies: 1) Grama by means of a scanner that performs a scan every few seconds. When it detects that a switch has been moved, it activates the device. 2) Extending a state: every few seconds, the device is activated for a second before turning off. If the switch is moved, then the device will not turn off after a second, and the “on” state is thus extended. 3) The device operates constantly at a certain level of power consumption. Flipping the switch merely increases the electrical current. This relies on the numerous poskim who maintain that electricity is forbidden on account of Molid, and consequently adding to the current is not forbidden. Moreover, according to Ĥazon Ish, the prohibition of electricity is based on Boneh, and if the electrical current already exists, it is not prohibited to add to the current. Based on this, they permitted use of a kalno’it. However, according to Rav Kook and those who agree with him, as described above in section 2, increasing a current is forbidden by Torah law. In general, the Zomet Institute relies on the rulings of R. Shlomo Zalman Auerbach, R. Yehoshua Neuwirth, and R. Ovadia Yosef, as detailed in several essays that have appeared in Teĥumin (the journal of contemporary halakhic issues published by the Zomet Institute).
Some say that since these devices were developed for this purpose, the leniency of grama does not apply to them at all. Rather, operating them has the same status as operating normal electrical devices. Moreover, these devices breach the walls that safeguard Shabbat. This is the position of Tzitz Eliezer 21:13; Orĥot Shabbat 29:27; Shvut Yitzĥak, Grama 15:15 in the name of R. Elyashiv; Ĥut Shani vol. 1, p. 206; Binyan Av 4:17. It is also implied in Responsa Aĥiezer 3:60. Certainly all of the reasons to be stringent apply to the kalno’it: according to Rav Kook and those who agree with him (above, section 2), increasing a current is forbidden by Torah law, and according to the remaining poskim, since it moves just as it would move during the week, one may not operate it on Shabbat. They also forbid the kalno’it because it breaches the walls safeguarding Shabbat and belittles its honor.
The proper approach seems to be the one we learned in 9:9 above. That is, a precondition for grama is that the action is done in a way that differs from the normal way of performing the melakha. As long as people perceive the device to be operating normally, it should not be permitted. Therefore, only if the delay is obvious and of significant duration does the device operate in a manner that sufficiently differs from the normal mode of operation on a weekday. Once the mode of operation is considered different, if the activation takes place via grama, that is, by means of a scanner, the removal of an impediment, or the extension of the present state, will it be permissible in a case of need, as is the rule in cases of grama. See Harĥavot.