Wristwatch and Owner Authentication Method Using Wrist Circumference

Anti-theft Wristwatch with Owner Authentication via Automatic Wrist Circumference Measurement

This technology features a wristwatch that automatically adjusts its strap to fit the wearer's wrist circumference and determines usage authorization by comparing the measured circumference against the registered owner's data. It consists of a watch module, a detachable strap, and an authentication unit equipped with memory, length adjustment, measurement, and judgment components.

While high-end watches are issued certificates of authenticity, it remains difficult to verify ownership in cases of theft or loss. Furthermore, existing smartwatches lack built-in anti-theft features, allowing unauthorized individuals to wear and use them without restriction.

This technology calculates wrist circumference by subtracting the strap's wound length from the circumference of the closed loop. If the measurement falls outside the margin of error, the strap extends to its maximum length, causing the watch to detach. The system updates the measurement with each authentication to account for changes in wrist size. Applicable to luxury watches and smartwatches, it prevents unauthorized use through the act of wearing alone, without requiring additional biometric sensors.

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Key Features:

• A watch module that displays the current time and a detachable strap that secures the module to the user's body.
• A length adjustment unit that winds or unwinds the strap to control its exposed length, and a measurement unit that calculates the circumference of the closed loop formed by the strap and watch module.
• A judgment unit that calculates the wrist circumference by subtracting the adjusted length from the total loop circumference and compares it against registered owner data to verify identity.
• A configuration that extends the strap to its maximum length if the measurement is outside the margin of error, rendering the watch unusable by causing it to detach, while updating the wrist circumference value upon successful authentication.

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