- Q. Dear Rabbi, Is there an issue walking past a motion-sensor LED light that is always on but increases its brightness when you walk by it? It should be noted that it is possible to see and walk even when the light is at its dim, baseline level. The question is being asked on behalf of Jews who live in an apartment building which recently installed such lights in all of the hallways. Thank you.
A. On question 537 we wrote:
“Q. I live in a condo complex, and my neighbor installed a Motion Detector for their lights. Is it a problem to walk passed the light even if it will go on?
A. Regardless whether the motion detector is of the passive or active kind (infrared, ultrasonic or electromagnetic-field sensitive), when there is no alternative passage to avoid tripping the device, it would be considered an unavoidable act of Shabbos desecration (p’sik reisho) and prohibited (see Igrois Moishe Y.D. 1: 173 – Shmiras Shabbos Kehilchoso 23: n. 146 – 39 Melochos p. 1214.)
The above applies when you desire and derive significant benefit from the light provided (nicho leih). If you do not, as when there is already enough light to walk by and there is no other option, Horav Shlomo Miller’s Shlit”a opinion is that it is permitted in a case of great need, for the sake of a mitzvah, and when there is no other option.
Therefore, you may want to provide your own permanent light for Shabbos on that area, to avoid needing and benefiting from your neighbor’s light.
A similar psak has been amply quoted in the name of Horav Yosef Shalom Elyashiv’s Zt”l. Namely that he ruled, if one is on the way to do a mitzvah, as in going to and from shul, he is permitted to walk past the motion detector light if there is no other way to go. (See Shmiras Shabbos Kehilchoso ibid. and Horav Shmuel Wosner, Tchumin 23 p.277)”
On question 3192 we added the following:
“Q. I live in a building that uses in the halls a new type of electric bulbs. When one comes close to them they go brighter and then, as one walks away they dim. It is an individual process of each bulb. Can these be used during Shabbos? I find it extremely difficult to have to move to another building.
A. Presence sensor “Smart Lights’ are divided into two kinds. They can be activated by motion sensors, and sensors that actually detect the infrared radiation emanating from people around them. These components are usually referred to as infrared sensors, or Passive Infra Red (PIR) sensors.
On question 675 regarding walking down a street on Shabbos and being careful when to not activate motion sensor lights, we wrote:
“Shemiras Shabbos Kehilchoso (23: 53) quoting Yesodei Yishurun (5: p. 160) prohibits entering through an automatic door operated by a sensor. A light likewise turned on would be similar. However when there is already enough light in the street and the additional one being activated by the sensor is unnecessary, it becomes a case of Pesik Reisho Delo Nicho Lei or a sure consequential act that provides no benefit, which Poskim permit when it is not intentional. Some Poskim would permit walking by the sensor even when the light provides benefit, if one closes the eyes (39 Melochos p. 1215.)
Horav Shlomo Miller”s Shlit”a opinion is that one should try to avoid activating the sensor when possible and to cross over to the other side of the street. When that is not an option it is permitted, if it is unintentional.”
The Rov maintains that the same would apply to the new Smart Bulbs. However he recommends using the infrared activated bulbs over the motion activated.
Rabbi A. Bartfeld as revised by, Horav Yaakov Hirschman, Horav Dovid Pam, Horav Aharon Miller, Horav Chanoch Ehrentreu and Horav Kalman Ochs Shlit'a - May 26, 2022
Important Numbers
