Sensor device

A sensor device comprising:

• a sensor unit configured to continue operating at least partially by being supplied with electric power from a battery though a power supply line while a starting switch is turned off, and including
• a sensing element configured to detect a change in a physical quantity in response to an operation of a detection target,
• a determination circuit configured to determine a power failure in which electric power is not supplied from the power supply line, which goes without through the starting switch, and
• a sensor communication unit configured to transmit sensor information including power failure information on whether the power failure has occurred;
• and
• a controller configured to operate by being supplied with the electric power through the starting switch, and including
• a control communication unit configured to receive the sensor information from the sensor unit and to transmit a return signal to the sensor unit commanding the sensor unit to reset the power failure information,
• a control calculator configured to perform a control operation using the sensor information, and
• a non-volatile memory configured to store the power failure information, wherein
• the controller is configured to obtain the power failure information from the sensor unit while the starting switch is off, store the power failure information in the non-volatile memory, and then transmit the return signal to the sensor unit.