Abstract: Space cleaning device includes: hypochlorous acid water generator; mixing bath storing a mixture of the hypochlorous acid water and water; hypochlorous acid water supply unit; water supply unit; water level sensor detecting a water level of the water mixture; humidifying purifier micronizing the water mixture and releases the water mixture micronized into air; and control unit controlling operations of hypochlorous acid water supply unit and water supply unit. Control unit is configured, after supplying the hypochlorous acid water and the water to fill mixing bath with the water mixture, controls an operation of hypochlorous acid water supply unit to supply a predetermined amount of the hypochlorous acid water to mixing bath once in every predetermined time period, and controls an operation of water supply unit to supply the water to mixing bath based on information related to the water level of the water mixture received from water level sensor.

Abstract: An air-fuel ratio sensing device includes a resistor, an A/D converter, a parallel circuit unit, a second switch, a controlling unit, an air-fuel ratio sensing unit, and a deterioration sensing unit. The controlling unit controls to turn off the first switch and controls to turn on the second switch in a first interval, and the controlling unit controls to turn on the first switch and controls to turn off the second switch in a second interval. The air-fuel ratio sensing unit senses an air-fuel ratio based on a converting result of the A/D converter in the first interval. The deterioration sensing unit compares a reference value with a value obtained based on the converting result and senses a deterioration generated in the current sensing circuit unit in the second interval.

Abstract: An air-fuel ratio sensing device includes a resistor, an A/D converter, a parallel circuit unit, a second switch, a controlling unit, an air-fuel ratio sensing unit, and a deterioration sensing unit. The controlling unit controls to turn off the first switch and controls to turn on the second switch in a first interval, and the controlling unit controls to turn on the first switch and controls to turn off the second switch in a second interval. The air-fuel ratio sensing unit senses an air-fuel ratio based on a converting result of the A/D converter in the first interval. The deterioration sensing unit compares a reference value with a value obtained based on the converting result and senses a deterioration generated in the current sensing circuit unit in the second interval.