Vehicle wheel condition monitor and data storage system

• US 5,656,993 A
• Filed: 05/08/1995
• Issued: 08/12/1997
• Est. Priority Date: 05/08/1995
• Status: Expired due to Fees

• Current Assignee: Semisystems, Inc.
• Original Assignee: Semisystems, Inc.
• Inventors: Coulthard, John J.
• Primary Examiner(s): Hofsass, Jeffrey
• Assistant Examiner(s): GHANNAM, MOHAMM
• Application Number:
  US08/436,167
• Time in Patent Office: 827 Days
• Field of Search: 340/442, 340/445, 340/447, 340/431, 73/146.4, 73/146.5, 73/146.8
• US Class Current: 340/442
• CPC Class Codes: B60C 23/009 having wheels on a trailer
• CPC Class Codes: B60C 23/0408 transmitting the signals by non-mechanical means from the wheel or tyre to a vehicle body mounted receiver
• CPC Class Codes: B60C 23/0433 Radio signals
• CPC Class Codes: G07C 5/008 communicating information to a remotely located station transmission systems for measured values G08C

Abstract

A tire monitor includes a pressure sensor, a temperature sensor, an A/D converter, and a microprocessor. The microprocessor has a sleep mode for conserving power and an output of the microprocessor controls the power applied to the pressure sensor and to the temperature sensor. A modulator and antenna are coupled to the microprocessor for transmitting data from the tire. Coupling between a monitor and a receiver is enhanced by extending a receiving antenna downwardly from the chassis of the vehicle, e.g. from the frame of a tractor.

The tire monitor is fabricated on a small printed circuit board with terminals for programming or encoding each monitor with a unique identification code during manufacture of the monitor. Terminals are also provided for disabling the transmitter with a jumper until the monitor is installed in a tire. The jumper is removed upon installation but the transmitter is further prevented by the microprocessor from transmitting until the pressure in a tire first exceeds a predetermined pressure. Transmissions occur at widely spaced intervals and the spacing depends on the content of the data. The number of times that the data is repeated within a transmission is also a function of the content of the data.

Claims

1. A wheel condition monitoring system comprising:

(a) a pressure sensing means for producing a first electrical signal proportional to air pressure;

(b) a temperature sensing means for producing a second electrical signal proportional to temperature;

(c) a microprocessor having a low power mode of operation, wherein said microprocessor is coupled to said pressure sensing means and to said temperature sensing means for turning off said pressure sensing means and said temperature sensing means when said microprocessor is in the low power mode of operation and for turning on said pressure sensing means and said temperature sensing means when said microprocessor is not in the low power mode of operation;

(d) a modulator coupled to said microprocessor for producing a modulated high frequency signal;

(e) an antenna coupled to said modulator for transmitting said modulated high frequency signal;

(f) said system having a plurality of conversion rates each associated with a range of change in a sensed temperature and a sensed pressure, each conversion rate having an unique transmission period associated therewith and a repeat number to determine the number of times that data is repeated during a transmission of said modulated high frequency signal.

2. A tire monitor comprising:

(a) a pressure sensing means for producing a first electrical signal proportional to air pressure;

(b) a temperature sensing means for producing a second electrical signal proportional to temperature;

(c) a microprocessor having a low power mode of operation, wherein said microprocessor is coupled to said pressure sensing means and to said temperature sensing means for turning off said pressure sensing means and said temperature sensing means when said microprocessor is in the low power mode of operation and for turning on said pressure sensing means and said temperature sensing means when said microprocessor is not in the low power mode of operation; and

(d) a first jumper terminal and a second jumper terminal coupled to said microprocessor, wherein said microprocessor enters said low power mode when said first jumper terminal is coupled to said second jumper terminal.

3. The tire monitor as set forth in claim 2 including a timer circuit coupled to said microprocessor for causing said microprocessor to exit said low power mode of the operation periodically and further including a first jumper terminal and a second jumper terminal coupled to said timer circuit for disabling said timer circuit when said first jumper terminal is coupled to second jumper terminal.