The use of computers is steadily increasing, including many crucial activities which can occur on Shabbat. More and more, a keyboard is not sufficient and it is necessary to use a computer mouse.
Security: Under computer control, gates can be opened from a distance, security cameras can be operated, an emergency phone number can be dialed, warning sounds can be turned off, and more. Such operations are typically performed with the aid of a mouse.
Health: A doctor is quite often required to fill out a medical form on a computer. For example, medicines can be chosen from a menu by clicking the mouse.
Industry: In many plants, a computer system controls the operation of the equipment (such as maintaining a specified temperature or pressure, etc). There are times when a single click on a mouse can prevent great financial loss (for example, food might spoil if a refrigerator has stopped working). Often, a rabbi who is consulted will allow the operators to perform such operations using a mechanism of gramma (indirect action), in order to prevent the loss.
A computer mouse works in two stages: First it is moved on a surface while being tracked by a cursor on the computer screen. Next, the mouse is clicked (usually once or twice) while the cursor rests on the desired object on the screen.
As it happens, a regular optic mouse, a device common in many computers today, is nothing more than a tiny camera. The camera moves with the mouse, and a computer program tracks the movement and draws the cursor on the screen. The way that such a mouse can be used on Shabbat is as follows: We have developed a special optical mouse where the red light that is tracked is always on (that is, it is not turned off when the mouse is at rest and then turned on again when it starts, as in normal operation). On the mouse, we have put two gramma switches, replacing the usual electrical contacts. One switch provides a single mouse click and the other one provides a double click. The way the mouse is used on Shabbat is very simple. It is moved on a flat surface in the normal way, since this operation of the camera is nothing more than a change in level of the current, which is permitted on Shabbat. Once the mouse reaches the desired point, one of the two gramma switches is pressed. The switches are checked automatically every few seconds. The next time they are checked, the desired operation will happen – a single or a double click of the mouse.
Rabbi Yehoshua Birnbaum has written a detailed analysis of the use of such a mouse in connection with security cameras in settlements and in the army. The rabbi notes that if no electric circuit is opened or closed the use of the mouse is permitted, "as is explained in halachic literature, in the name of our mentor Rabbi S.Z. Auerbach."
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