摘要 |
A pressure sensor portion includes a plurality of pressure sensors arranged in a plurality of rows and a plurality of columns inside a pressure-sensor-equipped carpet. The pressure sensor portion senses a pressure applied to the surface thereof and outputs a pressure value to a control portion. In an initial learning mode, a storage portion stores, as an initial value, the pressure value output from the pressure sensor portion. In a sensing operation mode, the control portion outputs to a modem portion a data signal indicating that an abnormal event is sensed, when the pressure value output from the pressure sensor portion is larger than the initial value stored in the storage portion by at least a prescribed threshold value. The modem portion superimposes the data signal received from the control portion on a power carrier wave (with a frequency of 50-60 Hz) and outputs the data signal to a power supply plug.
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