摘要 |
Provided is a dual acceleration sensor system usable for detecting impact, when strong impact works on a mobile device, and recording a history of applied impact, and workable with a low power consumption. It contains low range and high range acceleration sensors, a signal processing circuit, and/or an operation mode controller for switching signal between the two sensors and an operation mode of the signal processing circuit. The operation mode controller switches between a low range mode in which a signal from the low range acceleration sensor is processed at a low range operation rate and a high range mode in which a signal from the high range acceleration sensor is processed at a high range operation rate. It is judged whether data processed in the low range mode exceeds a first threshold or not, and if not, the low range mode continues, while the mode switches to the high range mode if it does. In the high range mode, when a state that the data is less than a second threshold continues for a predetermined period of time, the mode returns to the low range mode, and if not, the high range mode remains.
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