Apparatus for detecting the approach distance of a human body and performing different actions according to the detecting results

摘要

An apparatus for detecting the approach distance of a human body and performing different actions according to the detecting results comprises: an infrared sensing circuit for sensing the human body's movement; a short-distance infrared signal level detector, used for detecting the amplitude level of signals and comparing them with a preset reference level; a long-distance infrared signal level detector, used for detecting the amplitude level of signals and comparing them with another preset reference level; and a long-distance indication-signal time delayer, used for delaying the output of the signals from the long-distance-signal level detector. During the delayed period, a soft pre-recorded speech is sent off to greet customers and introduce merchandize when the short-distance-signal level detector detects a “short-distance” signal with larger amplitude, whereas a louder pre-recorded speech is sent off to draw the attention of customers when no “short-distance” signal is detected by the short-distance-signal level detector.

主权项

1. An apparatus for detecting the approach distance of a human body and performing different actions according to the detecting results, comprising:
an infrared sensing circuit, configured as a pyroelectric infrared sensor for sensing the human body's movement and outputting signals via an output end of an infrared signal amplifier; the infrared signal amplifier including plurality of resistors, wherein the plurality of resistors are in series with each other for voltage division to form at least one node, thereby providing a preset reference level; and a variable resistor connected with the infrared signal amplifier for adjusting the gain amplitude of the infrared signal amplifier and output signal; a short-distance infrared signal level detector including a plurality of diodes and an amplifier having three connected points; the plurality of diodes, respectively connected with the output end of the infrared signal amplifier and the first connected point of the amplifier, for attenuating input signal from the infrared signal amplifier; the second connected point of the amplifier being electrically connected with the node; wherein the amplifier is provided for detecting the level of output signals from the first connected point and comparing them with the preset reference level from the second connected point, such that if the signal level of the first connected point is higher than the preset reference level, then the amplifier will output a short-distance signal level via the third connected point; a long-distance infrared signal level detector including a plurality of diodes and an amplifier having three connected points; the plurality of diodes, respectively connected with the output end of the infrared signal amplifier and the first connected point of the amplifier, for attenuating input signal from the infrared signal amplifier, wherein the number of the diodes of the long-distance infrared signal level detector is less than that of the short-distance infrared signal level detector; the second connected point of the amplifier is electrically connected with the node; wherein the amplifier is provided for detecting the level of output signals from the first connected point and comparing them with the preset reference level from the second connected point such that if the signal level of the first connected point is higher than the preset reference level then the amplifier will output a long-distance signal level via the third connected point; a long-distance indication-signal time delayer, electrically connected to the long-distance infrared signal level detector, provided for delaying the output of the signals from the long-distance infrared signal level detector; wherein when a long-distance signal is detected by the long-distance infrared signal level detector, the signal from the output end of the long-distance signal level detector should be delayed for a period of time, wherein if the short-distance infrared signal level detector detects the short-distance signal level during the delayed time, an audio-frequency power amplifier outputs short-distance audio signals when the human is in a short distance from the apparatus; and wherein if the short-distance infrared signal level detector does not detect the short-distance signal level during the delayed time, an audio-frequency power amplifier outputs long-distance audio signals when the human is in a long distance from the apparatus when the delayed time is ended.