Question: May one turn off an alarm clock that goes off on Shabbat so that it does not cause unnecessary noise? Similarly, may one raise the button which will cause the alarm clock to ring throughout Shabbat on Shabbat?
Answer: In the previous Halacha we have explained the basis of why it is permissible to set an alarm clock before Shabbat to go off on Shabbat. We must now discuss whether or not it is permissible to push the button which will cause the alarm clock to stop ringing when the alarm clock goes off on Shabbat.
Regarding most alarm clocks commonly used nowadays which are electronic and pushing any button on the screen will usually cause an immediate action which will raise halachic concerns, we cannot offer a definitive answer, for we cannot possibly begin to discuss all of the various and technologically advanced alarm clocks available nowadays. Our discussion will therefore be limited to alarm clocks which work on a spring mechanism which is wound before the onset of Shabbat and by releasing it, the bell at the top of the clock will ring at the appropriate time.
Indeed, the entire basis for producing sound from a musical instrument on Shabbat is an edict of our Sages. Thus, even if it were forbidden to activate the alarm clock on Shabbat, stopping the ringing of the bell does not involve any prohibition whatsoever. This is therefore permissible without a doubt.
Regarding lifting the button that activates the bell on Shabbat so that alarm clock rings at the designated time on Shabbat, it would seem that this should be forbidden since lifting this button will cause a musical instrument to produce noise on Shabbat. Nevertheless, Maran zt”l rules that there is room for leniency in this situation as well, for lifting this button is not an action that immediately brings about the ringing of the bell; rather, this is merely an indirect action since the ringing will occur at a later time. (Any indirect action on Shabbat is treated more leniently from a halachic perspective such that this will serve as more of a basis for a lenient ruling.) Additionally, since activating the ringing of a bell is not exactly equivalent to playing a musical instrument on Shabbat, it is indeed permissible to lift the button of the alarm clock so that the bell will ring later on during the course of Shabbat.
Summary: One may not press any one of an electronic alarm clock’s buttons on Shabbat. Nevertheless, regarding a mechanical alarm clock which works on a spring, one may push the button on Shabbat which will cause it to ring at a later time. It is likewise permissible to raise the button in order to stop it from ringing when it goes off on Shabbat. (It is likewise permissible to set the hands of the alarm clock in place in order for it to wake the individual up at the correct time in order to attend the synagogue and the like.)
