Child monitor

• US 5,841,352 A
• Filed: 06/18/1997
• Issued: 11/24/1998
• Est. Priority Date: 06/18/1997
• Status: Expired due to Fees

• Current Assignee: Sushil Prakash
• Original Assignee: Sushil Prakash
• Inventors: Prakash, Sushil
• Primary Examiner(s): TONG, NINA C
• Application Number:
  US08/878,220
• Time in Patent Office: 524 Days
• Field of Search: 340/573, 340/539, 340/568, 340/571, 340/531, 340/572, 340/825.49, 342/127, 342/357, 342/450
• US Class Current: 340/573.4
• CPC Class Codes: G08B 21/0236 Threshold setting
• CPC Class Codes: G08B 21/0247 System arrangements wherein the alarm criteria uses signal strength

Abstract

A monitor system comprises first and second watches for wear by first and second users of the system. Each watch includes a battery therein for powering a transmitter and receiver. A signal limiter provides a base signal to a comparator so that the comparator can compare the base signal to a transmitted signal from one watch as received by the receiver of the other watch. Upon the received signal being less than the base signal, the comparator closes a relay which in turn energizes an alarm. The alarm indicates that an undesired amount of separation has occurred between the two watches. The strength of the signal produced by the signal limiter can be varied such that the desired degree of separation between the watches, which energizes the alarm, can be varied. A panic button is provided so that an alarm in one watch can be energized by the user of another watch irrespective of the distance between watches. The use of the monitor system in a watch-type configuration allows for its unobtrusive use.

Claims

1. An alarm system comprising:

first and second watches for wear by first and second users,

each watch having a transceiver assembly comprising;

transmitting means for sending a signal;

means for providing a periodic sending of said signals by said transmitting means;

receiver means for receiving said transmitted signals from the other watch;

means for powering said transmitting and receiving means;

signal producing means for producing a base signal indicative of a strength of a signal received by one watch if transmitted from the other watch at a preselected distance;

comparator means for comparing a signal transmitted by the other watch and received by said receiving means to said base signal produced in said watch receiving said signal, said comparator means producing a comparator signal upon a strength of said received signal from the other watch being less than a strength of said produced base signal;

a relay responsive to said produced comparator signal;

alarm means connected to said relay, a closure of said relay in response to said comparator signal connecting said power means to said alarm means, whereby to energize said alarm means, said energized alarm means indicative of one of said watches receiving a signal transmitted from the other watch from a distance beyond said preselected distance.

2. The device as claimed in claim 1 further comprising means for varying the strength of said base signal.

3. The device as claimed in claim 1 wherein said base signal decreases in value according to an increase in a said preselected distance of said watches.

4. The device as claimed in claim 1 further comprising means for reducing a strength of said received signal to less than said base signal, whereby to energize said alarm.

5. The device as claimed in claim 4 wherein said reducing means comprises a button on said watch to cease transmission of said signal, whereby said received signal strength is zero.

6. An alarm system comprising:

first and second housing for carrying by first and second users, each housing having a transceiver assembly comprising;

transmitting means for sending a signal;

receiver means for receiving a transmitted signal from the other assembly;

means for powering said transmitting and receiving means;

signal producing means for producing a base signal indicative of a strength of a signal received by one assembly if transmitted from another housing at a preselected distance, said signal producing means including means for varying the strength of said base signal;

comparator means for comparing a signal received by said receiving means to said base signal, said comparator means producing a comparator signal upon a strength of said received signal being less than a strength of said base signal;

a relay responsive to said comparator signal;

alarm means connected to said relay, a closure of said relay connecting said power means to said alarm means, whereby to energize said alarm means.

7. An alarm system comprising:

first and second housings for transport by first and second users, each housing having a transceiver assembly comprising;

transmitting means for sending a signal;

receiver means for receiving a transmitted signal from the other housing;

means for powering said transmitting and receiving means;

signal producing means for producing a base signal indicative of a strength of a signal received by one housing if transmitted from another housing at a preselected distance;

comparator means for comparing a signal received by said receiving means to said base signal, said comparator means producing a comparator signal upon a strength of said received signal being less than a strength of said base signal;

a relay responsive to said comparator signal;

a user-operable switch for closing said relay in the absence of said comparator signal;

alarm means connected to said relay, a closure of said relay by said comparator signal or said switch connecting said power means to said alarm means, whereby to energize said alarm means.