It’s prohibited to turn on light on Sabbath, but it’s all right to turn the light on with an automatic timer. But can we use a “clapping activated on/off switch”? Thank you!
The reason we can use the automatic timer is because it is set before shabbos and we are not doing anything on shabbos itself to turn it on. When your clapping turns the light on it is similar to during it on with your hand. Therefore it should not be done on shabbos