Patent Application
20080291010
1. Field of the Invention
The present invention relates to a security alarm system and more particularly, to a mother-daughter security alarm system, which indicates the moving direction of the daughter unit through a display of the mother unit so that the user of the mother unit can search the location of the daughter unit rapidly.
2. Description of the Related Art
Abduction and kidnapping cases are frequently reported in the media. When a young child is going out with his or her parents to a public, strange or crowded place, he or she may be attracted by events and forget to follow his or her parents. The parents may be unable to find their child when become aware that their child has missed in the crowd, resulting in a family tragedy. Further, when shopping or traveling abroad, people may forget to pick up one's personal precious items (wallet, luggage, bag, overcoat, etc.), resulting in a big loss or trouble.
To eliminate the aforesaid problems, mother-daughter security alarm systems are developed. A mother-daughter security alarm system for this purpose is comprised of a mother unit to be carried by the user, and a daughter unit to be carried on the user's child or personal item. A wireless communication continues between the mother unit and the daughter unit during the use of the mother-daughter security alarm system. When the daughter unit is out of the signal receiving range of the mother unit, an alarm of the mother unit is driven to output an alarm signal. A mother-daughter security alarm system of this design simply tells the user that the daughter unit has been moved out of the signal receiving range of the mother unit. It cannot tell the user of the moving direction of the daughter unit. The user may be unable to find out of the location of the daughter unit when searching in a different direction.
The present invention has been accomplished under the circumstances in view. It is therefore the main object of the present invention to provide a mother-daughter security alarm system, which indicates the moving direction of the daughter unit through a display in the mother unit so that the user of the mother unit can quickly search the location of the daughter unit. To achieve this and other objects of the present invention, the mother-daughter security system comprises a mother unit and a daughter unit for two-way wireless communication with the mother unit. The mother unit has multiple directional antennas arranged in different directions for receiving signal from the daughter unit, a microcontroller, and a display controlled by the microcontroller for displaying the moving direction of the daughter unit subject to the result of a comparison procedure made by the microcontroller to compare the value of the signal received from the daughter unit through one directional antenna with the value of the signal received from the daughter unit through another directional antenna. By means of the directional indication of the display, the user of the mother unit can search the location of the daughter unit rapidly.
Referring to
The mother unit 1 comprises a microcontroller 10, a wireless modulator/demodulator circuit 11 electrically connected to the microcontroller 10, a first directional antenna 111 and a second directional antenna 112 arranged in reversed directions and electrically connected to the wireless modulator/demodulator circuit 11, a switch 12 electrically connected to the microcontroller 10 and controllable by the microcontroller 10 to switch on the connection between one of the directional antennas 111 and 112 and simultaneously to switch off the connection between the other one of the directional antennas 111 and 112, an alarm 13 electrically connected to the microcontroller 10 and controllable by the microcontroller 10 to output an alarm signal, a display 14 electrically connected to the microcontroller 10 and controllable by the microcontroller 10 to output a visual directional indication signal, and a geomagnetic sensor 15 electrically connected to the microcontroller 10.
The daughter unit 2 comprises a microcontroller 20, a wireless modulator/demodulator circuit 21 electrically connected to the microcontroller 20, a transmission antenna 211 electrically connected to the wireless modulator/demodulator circuit 21, an alarm 22 electrically connected to the microcontroller 20 and controllable by the microcontroller 20 to output an alarm signal, and a display 23 electrically connected to the microcontroller 20 and controllable by the microcontroller 20 to output a visual status signal.
The aforesaid alarm 13 or 22 can be a buzzer, voice synthesizer, light emitting device or vibrator for producing a sound, voice, light or vibration signal. The display 14 or 23 can be formed of light emitting devices or a display screen.
During application, the daughter unit 2 is carried on one personal item or a baby cart, and a user carries the mother unit 1. The mother-daughter security alarm system is then operated subject to the steps:
By means of the display 14, the mother unit 1 indicates the direction and intensity of the detected signal that is indicative of the distance between the mother unit 1 and the daughter unit 2. If the daughter unit 2 is out of a signal receiving range of the mother unit 1, the alarm 13 of the mother unit 1 will be immediately driven to output a sound, voice, light or vibration alarm signal. By means of the directional indication of the display 14 subject to the aforesaid operation procedure, the user can search the location of the daughter unit 2 quickly. When the daughter unit 2 entered a set detection range relative to the user with the mother unit 1, the alarm 13 is off, and the user can keep searching the location of the daughter unit 2 within the set detection range.
By means of the geomagnetic sensor 15, the user can judge own current azimuth (determination of loxodrome, such as the south pole, the north pole, et.) for use as a reference value for searching the location of the daughter unit 2 so as to obtain the azimuth (azimuth east, azimuth south, azimuth west, azimuth north) of the daughter unit 2 quickly. Further, when searching the location of the daughter unit 2, the user can operate the switch 12 to let the wireless modulator/demodulator circuit 11 output a wireless signal through the first directional antenna 111 or the second directional antenna 112 to the daughter unit 2 subject to the control of the microcontroller 10. If the daughter unit 2 is within the detection range of the mother unit 1 at this time, the wireless signal will be received by the transmission antenna 211 of the daughter unit 2 and demodulated by the wireless modulator/demodulator circuit 21 to drive on the alarm 22 subject to the control of the microcontroller 20. By means of the warning of the sound, voice, light or vibration alarm signal of the alarm 22 of the daughter unit 2 and the directional indication of the display 14 of the mother unit 1, the user can soon find out the location of the daughter unit 2 (i.e., the location of the user's personal item or baby cart).
Further, the microcontroller 20 of the daughter unit 2 has electrically connected with a geomagnetic sensor 25 (see
When compared to a similar conventional mother-daughter security alarm system, the invention uses multiple directional antennas for examining the moving direction of the daughter unit precisely. When the daughter unit 2 is out of the signal receiving range of the mother unit 1, the user of the mother unit 1 can search the location of the daughter unit 2 rapidly subject to the directional indication of the display 14 of the mother unit 1, at the same time, the geomagnetic sensors 15 and 25 provide an azimuth reference value of the daughter unit 2 and the mother unit 1 respectively.
Although particular embodiments of the invention have been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention. Accordingly, the invention is not to be limited except as by the appended claims.
