Patent ID: 6326891
Filing Date: 2001-12-04
Classification: G08B

Abstract:
A warning device for preventing a child from being lost comprising a high frequency host transceiver and a plurality of high frequency slave transceivers, wherein said host transceiver is adjustable in multi-stage security range from bi-directional communication with each slave transceiver; said host transceiver is basically carried by the parents while each slave transceiver is secured on a child respectively, when said slave transceiver has received a signal and confirmed an inner code sent from said host transceiver, said slave transceiver will in response transmit a reply signal to said host transceiver as a confirmation of receipt of the signal from said host transceiver, and no warning alarm will be triggered at this time; and, on the contrary, when said slave transceiver departs from said host transceiver beyond the present security range, both said host and said slave transceiver will start alarming to warn both ends for preventing the child from being lostwherein said high frequency host transceiver comprises:a single-chip microprocessor which is programmed to operate with associated hardware;a clock generator used to provide clock pulse for the microprocessor;a high frequency transmitter used to transmit signals to said slave transceiver;a high frequency receiver used to receive signals transmitted from said slave transceiver and relay the signals to a following high frequency filter;a warning unit including a vibration motor and a speaker, which will vibrate and sound when an effective output signal is activated by said microprocessor;a power supply controller used to control action order of said high frequency transmitter and said high frequency receiver based on an output signal of said microprocessor;a power supply unit used to provide a 4.5 V DC power to said host transceiver;a high frequency filter used to filter an input signal received by said high frequency receiver, then relay it to a following signal amplifier;a signal amplifier used to amplify an output signal from said high frequency filter, a distance controller, or said power supply controller, then relay the amplified signal to said microprocessor or a following voltage regulator;a voltage regulator used to regulate voltage of an amplified signal from said signal amplifier and feed back to said high frequency receiver for stabilization;a distance controller used to preset distance in 3 stages, namely, 2 m, 4 m and 8 m, for controlling transmission power of said host transceiver, or, to adjust in different stages according to respective distance between said host transceiver and each said slave transceiver;a display unit containing a plurality of LEDs which represents a plurality of slave transceivers respectively and when slave transceiver is located within the preset security range, the corresponding LED is darkened, or it is lightened otherwise; anda voltage detector used for detecting voltage of said power supply unit to make sure if it is still workable for said host transceiver.