A sensor for detecting an acceleration on a surface. In response to detecting the failed communication channel, failover instructions are generated concerning an alternative communication channel. This structure can thus alleviate excessive heating around the aperture, and allow the heating coil to produce a high output power for a long duration of time even when an inwardly concaved pan is used. The sensors measure the velocity of air current traveling through the illuminating device and outputting the velocity of the air current as an analog electrical signal.