Abstract: A circuit for measuring a pulse width of a remote control signal comprises a receiver for receiving a remote control signal exhibiting at least one pulse; an amplifier for shaping and amplifying the received remote control signal to produce a corresponding output signal; a counter having an output which changes from first to second logic states in response to reception of a falling edge of a first pulse of the output signal and simultaneously making a first count of clock pulses that is cleared at the falling edge of each pulse of the output signal; and a microprocessor. When the value of the first count reaches a first predetermined value equivalent to an output signal pulse period and a selected delay, the output changes back to the first logic state. The selected delay is set longer than the period of each pulse so that the first count does not reach the first predetermined value before arrival of another pulse within a waveform of the output signal.

Abstract: An automatic water injector for a wet mop cleaner and an operation method thereof which detects the soil level of a mop so as to automatically inject washing water thereto, wherein the water injector has a soil level detector for detecting the soil level of the mop, a controller for controlling the water injection depending on the detected soil level, a water absorber operated under the control of the controller and a water injector operated under the control of the controller. The method includes driving the mop in accordance with a user input, determining if the mop needs to be washed by detecting the soil level of the mop and comparing the detected level with a predetermined standard level, washing the mop if the comparison determines the need for washing the mop and stopping the mop operation according to stop key input. Accordingly, a proper quantity of water corresponding to the soil level of the mop is automatically injected, to thereby provide convenience to users.