The invention discloses a sensing
water depth range-
viewfinder and an operation method thereof. The sensing
water depth range-
viewfinder comprises an indicator light, a
humidity sensor, a marker post,a displacement sensor, an annular float and a power supply for supplying power. The indicator light is installed at the top of the marker post; and the
humidity sensor is installed at the upper partof the marker post, the
humidity sensor comprises a hygristor and an
electromagnet used for controlling the displacement sensor, and the
electromagnet is activated by output current of the hygristor.The displacement sensor is installed at the lower part of the marker post and extends outwards, the displacement sensor comprises a slide rheostat, a sender unit and an
ampere meter, the annular floatis installed at the lower part of the marker post in a sleeving mode, the slide rheostat is connected with the annular float, the annular float pulls the slide rheostat to change a resistance value,the current output by the slide rheostat is converted into depth through the
ampere meter, the displacement sensor judges whether the
measured depth is more than the height of an automotive
chassis ornot, and if the depth is more than the height of the automotive
chassis, a danger
signal is sent to a vehicle owner by the sender unit. The sensing
water depth range-
viewfinder and the operation method can accurately detect the depth of a flooded road section, and a
flameout accident caused by travelling in water of a vehicle is avoided.