Alarm system

• US 6,011,471 A
• Filed: 02/03/1999
• Issued: 01/04/2000
• Est. Priority Date: 02/03/1999
• Status: Expired due to Fees

• Current Assignee: Dennis Huang
• Original Assignee: Dennis Huang
• Inventors: Huang, Dennis
• Primary Examiner(s): Hofsass, Jeffery A.
• Assistant Examiner(s): TRIEU, VAN THANH
• Application Number:
  US09/243,436
• Time in Patent Office: 335 Days
• Field of Search: 340/568.1, 340/568.7, 340/571, 340/572.1, 340/686.1, 340/686.5, 340/686.6, 340/539, 340/572.8
• US Class Current: 340/568.1
• CPC Class Codes: G08B 13/1418 Removal detected by failure in electrical connection between the appliance and a control centre, home control panel or a power supply
• CPC Class Codes: G08B 13/1427 with transmitter-receiver for distance detection
• CPC Class Codes: G08B 21/023 Power management, e.g. system sleep and wake up provisions
• CPC Class Codes: G08B 21/0286 Tampering or removal detection of the child unit from child or article
• CPC Class Codes: G08B 21/0288 Attachment of child unit to child/article

Abstract

An alarm system for an electronic apparatus with a slot comprises a radio transmitter unit and a radio receiver unit. The radio transmitter unit can be carried by a user, including an antenna for transmitting a radio code signal and a control switch for controlling power on/off of the radio receiver unit. The radio receiver includes a security switch controlled to turn on/off the radio receiver unit when inserting/removing from the slot of the electronic apparatus. The radio receiver unit automatically outputs an alarm signal when moved away from the electronic apparatus beyond a predetermined distance due to being incapable of receiving the code signal from the radio transmitter unit.

Claims

1. A alarm system for use with an electronic apparatus having a slot, comprising:

a radio transmitter unit, said radio transmitter unit comprising a transmitting circuit and a transmitting control device controlling on/off said transmitting circuit, said transmitting circuit comprised of an encoder, a radio signal transmitter, a control switch, and a transmitting antenna, said encoder outputting a code signal to said radio signal transmitter when turned on said transmitting control device, enabling the code signal to be transmitted through said transmitting antenna into the air by radio; and

a radio receiver unit for insertion into the slot of the electronic apparatus, said radio receiver unit comprising a casing fitting the slot at the electronic apparatus, a receiving antenna, which receives the code signal from said radio transmitter unit within a predetermined distance between said radio transmitter unit and said radio receiver unit, a decoder, which recognizes the code signal received by said receiving antenna, an alarm device, a receiving control device, which drives said alarm device to output an alarm signal when said receiving antenna receives no signal from said radio transmitter unit, and a security switch controlled to turn on/off said radio receiver unit.

2. The alarm system of claim 1 wherein said radio transmitter unit further comprises a transmitting time sequence circuit, which controls the transmitting frequency of said code signal per every unit time.

3. The alarm system of claim 1 wherein the control switch of said radio transmitter unit controls alert/disarm of said radio receiver unit.

4. The alarm system of claim 1 wherein the control switch of said radio transmitter unit controls power on/off of said radio receiver unit.

5. The alarm system of claim 1 wherein said receiver unit further comprises a switch controlled by said radio transmitter unit to turn on/off power supply of said radio receiver unit.

6. The alarm system of claim 1 wherein the control switch of said radio transmitter unit controls the security switch of said radio receiver unit.