Sensor device

A sensor device capable of continuing to operate at least partially with electric power supplied from a battery during a period when a starting switch is turned off, the sensor device comprising:

• a sensor input processor including
• a sensor element configured to detect a change in a physical quantity in response to movement of a detection target,
• an input processing circuit configured to calculate sensor information according to the detected value of the sensor element, and
• a memory configured to store abnormality information including power failure information pertaining to a power failure in which electric power is not supplied from the battery during the period when the starting switch is turned off;
• and
• a voltage holding circuit provided on a battery feed line which supplies battery power to the sensor input processor without going through the starting switch, and capable of applying a voltage to the sensor input processor sufficient to retain at least data in the memory during a temporary voltage drop in the battery, wherein
• the sensor input processor has an adjustment circuit configured to sequentially stop functions other than data retention in the memory based on a voltage of the voltage holding circuit when the voltage of the voltage holding circuit drops.