Variation detection device, data communication apparatus, and method of detecting variation

A data communication apparatus comprising:

• a processor;
• a pressure sensor;
• an AD converter converting a signal voltage output from said pressure sensor to generate an AD converted value and outputting said AD converted value to said processor;
• a temperature sensor detecting a temperature of said pressure sensor;
• a memory storing a table which indicates a relationship between temperatures and initial pressure values;
• a receiving circuit supplying a received command signal to said processor;
• and
• a transmission circuit,
• wherein when receiving said AD converted value, said processor identifies a temperature of said pressure sensor based on an output of said temperature sensor, reads out an initial pressure value corresponding to said identified temperature from said table stored in said memory, calculates a variation between said initial pressure value and said AD converted value, and outputs a variation data indicative of said calculated variation through said transmission circuit.

A vehicle comprising:

• a data transmission apparatus;
• and
• a data receiving apparatus configured to receive a variation data transmitted from said data transmission apparatus,
• wherein said data transmission apparatus includes:
• a processor;
• a pressure sensor measuring a tire pressure of said vehicle;
• an AD converter converting a signal voltage output from said pressure sensor to generate an AD converted value and outputting said AD converted value to said processor;
• a temperature sensor detecting a temperature of said pressure sensor;
• a memory storing a table which indicates a relationship between temperatures and initial tire pressure values;
• a receiving circuit supplying a received command signal to said processor;
• and
• a transmission circuit,
• wherein when receiving said AD converted value, said processor identifies a temperature of said pressure sensor based on an output of said temperature sensor, reads out an initial tire pressure value corresponding to said identified temperature from said table stored in said memory, calculates a variation between said initial tire pressure value and said AD converted value, and outputs said variation data indicative of said calculated variation through said transmission circuit to said data receiving apparatus.

A method of detecting a variation of tire pressure comprising:

• (A) providing a memory which stores a table which indicates a relationship between temperatures and initial tire pressure values;
• (B) providing a pressure sensor configured to measure said tire pressure;
• (C) AD converting a signal voltage output from said pressure sensor to generate an AD converted value;
• (D) identifying a temperature of said pressure sensor in response to said AD converted value;
• (E) obtaining an initial tire pressure value corresponding to said identified temperature from said table stored in said memory;
• and
• (F) calculating a variation between said initial tire pressure value and said AD converted value.