Mitsubishi Electronics JT-SB216DS-W-AUS manual Hand detection and hand dryer operation

(2) Hand detection and hand dryer operation

1Each of the top and bottom hand detection sensors is an infrared radiation sensor mainly consisting of a light emitting sensor (infrared LED) and a light receiving sensor (photodiode).

2The light emitting sensors of the top and bottom hand detection sensors continuously emit pulses.

3When a hand is inserted into the hand-drying area, the lights from the light emitting sensors are blocked; thus, there will be no output from the light receiving sensors. Through this, the hand dryer detects that a hand has been inserted into the dryer.

4When the bottom hand detection sensor detects a hand, the blow motor is turned ON and the operation starts.

5Once the operation has started, it continues as long as either the top or bottom hand detection sensor detects a hand.

6After that, if one second elapses while both the top and bottom hand detection sensors do not detect a hand, the blower motor is turned OFF, and the operation stops.

7The hand dryer continuously operates up to 30 seconds.

•Once 30 seconds have elapsed, the hand dryer stops operating even if the top or bottom hand detection sensor detects a hand.

•This is a feature that assumes the presence of a foreign matter in the hand-drying area. The hand dryer will resume its operation when a hand is removed once and then inserted again.

(3)Control of the blower motor

1A DC brushless motor is used as a blower motor. It does not have a Hall sensor that detects the position of the rotor. Instead, it is driven by determining the position of the rotor and the direction of rotation by the back electromotive force (voltage) of the motor winding.

2The microcomputer (IC1) drives the blower motor by controlling the MOSFET (driving transistor) at a power stage via the drive IC (IC2).

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