| CPC F04D 27/008 (2013.01) [F04D 25/06 (2013.01); F04D 27/004 (2013.01); G01S 17/08 (2013.01); G01S 17/58 (2013.01); G01S 17/88 (2013.01); G08B 21/182 (2013.01); F04D 25/088 (2013.01)] | 9 Claims |
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1. A ceiling fan configured to hang from an installation surface, comprising:
a carrier unit adapted to be connected to the installation surface;
a motor mounted to said carrier unit;
a fan body disposed to be driven by said motor to rotate relative to said carrier unit;
a light sensing unit mounted to said carrier unit, and configured to emit a light signal, to receive the light signal reflected by an object, and to output a first signal that is related to a round trip time of the light signal; and
a control unit being electrically connected to said motor and said light sensing unit, and being configured to perform a safety procedure when said fan body is rotating at a user-defined rotational speed;
wherein said control unit is configured to, in the safety procedure,
calculate, using a time-of-flight principle, a distance between the object and said ceiling fan based on the first signal outputted by said light sensing unit, and an object speed of the object relative to said ceiling fan based on a change in the distance over time,
control said motor to rotate said fan body at a predetermined rotational speed when the distance is between a first distance threshold and a second distance threshold that is smaller than the first distance threshold, wherein an value of the predetermined rotational speed is smaller than the user-defined rotational speed,
control said motor to stop rotating said fan body when the distance is smaller than the second distance threshold, and
control said motor to rotate said fan body at the predetermined rotational speed when the object speed is greater than a speed threshold and when the distance is not smaller than the second distance threshold.
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