| 摘要 |
PROBLEM TO BE SOLVED: To sustain operation for a longer time regardless of degrading in detecting capability, instead of allowing power supply to run down and a microwave detector to become completely inoperative, by switching between power- saving mode and ordinary mode during use depending on situations. SOLUTION: There are two types of the control operation of a controller 15: Ordinary mode (more power is consumed but microwaves are favorably detected) and power-saving mode (the capability to detect microwaves is sacrificed but less power is consumed), and the mode is switched through the output of a voltage monitoring circuit 16. The voltage monitoring circuit 16 monitors the output of a power supply battery 12 at all times. When the voltage of the battery 12 is above a predetermined reference value, the output of the voltage monitoring circuit 16 is high. At this time the controller 15 operates in the ordinary mode. If the voltage of the battery 12 falls below the reference value, the output of the voltage monitoring circuit 16 changes to low. At this time, the controller 15 operates in the power-saving mode. Thereby influences of degradation in performance due to power saving can be minimized. |
