Motion Sensors on Shabbos

A Rav told me (about light sensors in the street) that he once asked R’ Shlomo Zalman Aurbach zt”l and he paskened that “A sensor is a switch”, and it is assur. I asked the Rav what he would do if he realised he is in front of a sensor – would he stay there the whole shabbos – and he said that he would be soimech on the makilim (e.g R’ Shmuel Vosner in Shevet HaLevi).

(My Rav also paskened, based on R’ S Z Aurbach, that if you have a light in front of your house that will go on automatically, you must stay at home the whole shabbos and daven beyechidus!)

I find this shaila interesting.

If you Google “motion sensor toilet shabbos”, sans quotes, you will find discussions on this precise topic.

“Psik raisha d’lo nicha lei” and “kavod habriyos” figure prominently in those discussions.

Rav Wosner from Monsey said in a Shiur that it is fine, since it is not you that put that in place as much as the host.

I’m not sure secularfrummie good question. Thanks ICOT.

I would think that there is an obvious Chiluk between if walking in front of the sensor flushes the toilet and if leaving being in front of the sensor flushes the toilet. Leaving the sensor Mistama is a Grama. Walking in front of the sensor, according to R’ Shlomo Zalman (and what seems the Pashtus) is a Ma’aseh and probably a P’sik Reisha D’nicha Leih (you really don’t want that stuff sitting in the toilet) and you would probably have to stay there all Shabbos (or try rolling out under the sensor if you know exactly where it is).

ROB – The Rav told me it is assur, quoting R’ Shlomo Zalman’s words “A sensor is a switch”. This isn’t my psak; MY Rav told me actually that it is muttar and i do walk past light sensors. THIS Rav told me his psak, quoting R’ Shlomo Zalmans words.

The Rav did try to bring in cameras (live recording) into this shaila, (although not l’maisa, he was talking based on the {debatable} principal that taking a photo will be ????, which he is ????? may not be ???? with digital), but that isn’t what he spoke to R Shlomo Zalman about.

(If anybody has the ??? handy, have a look at R’ Elyashivs Hagodo (brought out this year) under ????? ???? ????? where they quote some rather amusing stories about questions people asked R’ Elyashiv and got a very confusing psak based on the way they phrased the question.)

yekke2 –

With regard to the case of the light in front of the house: while a sensor may be a switch, min hastam you have no idea which step will cause the light to go on/off. Therefore each step is a davar she-eino miskaven, which is mutar, because every davar she-eino miskaven that does not inevitably cause a melacha is mutar. This isn’t only my logic; I have heard this from many rabbanim.

With regard to the toilet case, there are a number of factors to consider, including: 1) It is kil’achar yad (probably what Sam meant), since you are simply getting up to go on your way. While R’ Shlomo Zalman was known to hold that if this is the way it is always done it is not called kil’achar yad or grama, this is a chiddush which others reject. 2) R’ Shlomo Zalman himself would undoubtedly maintain that the electronic mechanism that makes the toilet flush is not d’oraisa. Therefore one can apply principles such as kevod habriyos, tza’ar, oneg Shabbos, etc. to say that one is not obligated to hold it in or stay in the bathroom all Shabbos.

Sam2 –

I am not sure what you are referring to. If you mean R’ Shlomo Zalman’s chiddush of “the normal way” precluding kil’achar yad, I don’t know what you mean by haskamas haposkim. It just isn’t true; I’ve heard many poskim mention kil’achar yad as a valid point when it comes to opening refrigerator doors, turning on hot water faucets, etc. Kil’achar yad is still assur mid’rabbanan. As for your point that “otherwise, we could remove all M’lachos D’Oraisa Bizman Hazeh by using Gramas or electronics”; that is not a halachic argument.

With regard to the davar she-eino miskaven point: As I said, it is not just my reasoning, but something I have heard from a number of prominent rabbanim.

For example, R’ Tuvia Goldstein told someone I know that for a man to comb hair normally is not a psik reishe even though during the course of the combing hair will certainly be plucked out, since each individual time combing motion is not a psik reishe. He explained his reasoning in precisely this manner; i.e. that although the entire combing session presents a psik reishe, each individual combing motion does not. I have also been told by, or heard secondhand from at least three rabbanim that it is okay to walk in front of a house that has a light run by a motion sensor that will certainly go off; presumably by this reasoning. I have also heard other psakim that rely on this reasoning.

Dayan Rav Ephraim Friedman, Shlit”a (the country’s most accessible and competent posek, LA”D) of Chicago told me years ago that according to Rav Sholomo Zalman, ZTK”L, it’s not a ma’aseh therefore it’s nothing and you need not take any specific precautions.

http://www.theyeshivaworld.com/coffeeroom/rss/topic/motion-sensors-on-shabbos in some situations, you can cheshbon in psik reisha d’lo ichpis lei.

I am curious as to what type of place one would be in for a Shabbos, that would have activated motion sensors functioning on Shabbos?

It happened to me in a hospital.