This switch, when hidden under the floor mat, triggers an alarm when the person walks over it. Mat switch can be used as a security measure in a restricted area. [[wysiwyg_imageupload::]]Just put the switches beneath the mat after regular intervals so that when anybody who puts his feet on switch will engage the alarm.This circuit is built around the CMOS UM3561 IC which is mostly used in toys and alarms because of its low cost and power saving ability.One of the advantages of this switch is that the circuit does not consume the battery current in standby mode therefore lead to longer battery life.  Also, you can also stabilize 9V DC mains adaptor in place of the battery. Read more to find out how the circuit is designed and how it works.