Time based low tire pressure warning sensor
First Claim
1. In a low tire pressure warning system having a transmitter and a pressure sensor wherein the transmitter has a sleep mode of low energy consumption, a wake mode of normal energy consumption and a transmission timer, a method of using the transmission timer for intermittently transmitting a pressure message comprising the steps of:
- periodically entering the wake mode and determining whether the transmission timer indicates that it is time to transmit a pressure message;
when the transmission timer indicates that it is time to transmit a pressure message,transmitting a status report,selecting a random time within a prescribed time range,initializing the transmission timer with the selected random time, andreturning to the sleep mode.
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Accused Products
Abstract
A battery powered sensor in a tire has a microprocessor and a transmitter circuit permanently connected to a battery and a pressure switch or pressure sensor coupled to the microprocessor. The microprocessor has a sleep state and wakes up every few minutes to execute an algorithm which determines on a time basis whether to read the pressure state and transmit a report of significant changes, and determines on a randomly timed basis whether to transmit a status report. A factory test state permits only one signal transmission when the tire is inflated and inhibits other signals for a period to allow testing of many tires without interference from one another.
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Citations
7 Claims
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1. In a low tire pressure warning system having a transmitter and a pressure sensor wherein the transmitter has a sleep mode of low energy consumption, a wake mode of normal energy consumption and a transmission timer, a method of using the transmission timer for intermittently transmitting a pressure message comprising the steps of:
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periodically entering the wake mode and determining whether the transmission timer indicates that it is time to transmit a pressure message; when the transmission timer indicates that it is time to transmit a pressure message, transmitting a status report, selecting a random time within a prescribed time range, initializing the transmission timer with the selected random time, and returning to the sleep mode. - View Dependent Claims (2, 3, 4, 5)
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6. In a low tire pressure warning system having a factory test state for pressurizing a tire and an in-use state, the system including a transmitter and a pressure sensor wherein the transmitter has a sleep mode of low energy consumption and a wake mode of normal energy consumption, the method of intermittently transmitting a pressure message comprising the steps of:
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periodically waking the transmitter from the sleep mode and checking an IN-USE flag; if an IN-USE flag is not set, entering a factory test state and then setting the IN-USE flag a delay time after the tire is pressurized; if the IN-USE flag is set, entering the in-use state and then transmitting a status report at selected times, and periodically monitoring the pressure sensor for changes and transmitting a warning when a significant pressure change is detected. - View Dependent Claims (7)
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Specification