Fingerprint locks primarily function by using a capacitor to detect and record the unique ridges and valleys of your fingerprint.
Here's a breakdown of the process:
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Capacitive Sensing: The core of many fingerprint locks is a tiny capacitor array. A capacitor stores electrical charge. When your finger touches the scanner surface, the ridges and valleys interact differently with these capacitors.
- Ridges: Where your fingerprint ridges make contact, they influence the capacitor's ability to store charge, creating a voltage change.
- Valleys: Where there's an air gap (the valleys), the capacitor is less affected, resulting in a different voltage reading.
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Data Acquisition: These fluctuations in voltage are meticulously measured and converted into a digital fingerprint map. Essentially, the sensor detects the tiny differences in electrical current flow that are created by the unique pattern of your fingerprint.
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Template Creation: The fingerprint lock's system then creates a digital "template" from this map. This template is a mathematical representation of your unique fingerprint pattern. Note that the lock doesn't store an image of your fingerprint; it stores this abstract digital representation.
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Comparison and Authentication: When you subsequently place your finger on the scanner to unlock it, the process repeats. The sensor creates a new template, and the system compares it to the stored template. If there's a sufficient match (within a predefined tolerance level), the lock mechanism is triggered, granting access.
In essence, fingerprint locks don't "see" your fingerprint like a photograph. They measure the electrical characteristics of your fingerprint's ridges and valleys and compare these measurements to a stored representation to verify your identity.
