A smart trash receptacle, comprising a trash bag fitting device and a trash bag detection device; wherein the trash bag fitting device is configured to fit a trash bag into a main body of the smart trash receptacle, wherein the trash bag fitting device comprises a vacuum assembly and a motor for driving the vacuum assembly, the vacuum assembly comprising an air inlet and an air outlet, the air inlet in communication with the inside of the main body of the trash receptacle, the air outlet in communication with the outside of the main body of the trash receptacle; wherein the trash bag detection device comprises a transmitter for transmitting a signal and a receiver for receiving a signal, both the transmitter and the receiver being disposed on internal surfaces of the trash receptacle, wherein the signal received by the receiver is a direct signal transmitted from the transmitter; wherein the trash bag detection device further comprises a control mechanism, wherein each of the transmitter, the receiver and the trash bag fitting device is communicatively coupled to the control mechanism, wherein the control mechanism is configured to control an operational status of the trash bag fitting device based on the signal received by the receiver, and wherein in the event of a trash bag being present between the receiver and the transmitter, the receiver produces a first sense signal based on which the control mechanism instructs the trash bag fitting device to stop its operation; wherein i) the transmitter is disposed on an internal bottom surface of the trash receptacle and the receiver on an internal side surface thereof so that a central transmission axis of the transmitter is oriented at an angle α of 30-50 degrees with respect to the internal bottom surface of the trash receptacle and that a central reception axis of the receiver is oriented at an angle β of 38-58 degrees with respect to a vertical direction for the internal side surface of the trash receptacle; or ii) the receiver is disposed on the internal bottom surface of the trash receptacle and the transmitter on the internal side surface thereof so that the central reception axis of the receiver is oriented at an angle α of 30-50 degrees with respect to the internal bottom surface of the trash receptacle and that the central transmission axis of the transmitter is oriented at an angle β of 38-58 degrees with respect to the vertical direction for the internal side surface of the trash receptacle. i) the transmitter is disposed on an internal bottom surface of the trash receptacle and the receiver on an internal side surface thereof so that a central transmission axis of the transmitter is oriented at an angle α of 30-50 degrees with respect to the internal bottom surface of the trash receptacle and that a central reception axis of the receiver is oriented at an angle β of 38-58 degrees with respect to a vertical direction for the internal side surface of the trash receptacle; or ii) the receiver is disposed on the internal bottom surface of the trash receptacle and the transmitter on the internal side surface thereof so that the central reception axis of the receiver is oriented at an angle α of 30-50 degrees with respect to the internal bottom surface of the trash receptacle and that the central transmission axis of the transmitter is oriented at an angle β of 38-58 degrees with respect to the vertical direction for the internal side surface of the trash receptacle.