This technology is a lot harder to bypass since an image cannot get passed capacitive fingerprint sensor and other materials will record different changes in charge on the capacitor. Figure 2 shows the physics behind this.įigure 2: How a capacitive fingerprint scanner captures digital images (Source: Android Authority/Robert Triggs) An operational amplifier integrator circuit tracks these changes that can then be recorded by an analog-to-digital converter, where this digital data can be analyzed. It uses the ridges of your fingerprint that is placed over the conductive plates which changes the charge stored in the capacitor, while the valleys (air gaps) leave the charge on the capacitor unchanged. To go into more detail, the capacitive fingerprint scanner uses tiny capacitor array circuits that track the detail of a fingerprint. Similar to the capacitive touchscreen, it measures your finger by using human conductivity, creating an electrostatic field, and creating a digital image based on the electrostatic field. In today’s world, capacitive fingerprint scanners are more common and found on phones. (Source: Android Authority/Robert Triggs) Capacitive Fingerprint Sensors The disadvantage to this, while highly unlikely, is that a digital photo can be replicated.įigure 1: Light source taking a digital image of a fingerprint. Figure 1 shows how the light source reads the fingerprint and where that information goes. The light-sensitive microchip makes the digital image by looking at the ridges and valleys of the fingerprint, turning them into 1’s and 0’s, and creates the user’s own personal code. The way an optical scanner works is by shining a bright light over your fingerprint and taking a digital photo. Optical fingerprint sensors have been around for a while. How Does a Fingerprint Optical Scanner Work? There is two common ways that fingerprint sensors are being used today and that is optical and capacitive. Whether you want to secure your phone or identify yourself before you enter a building, fingerprint sensors can add security and identification easily.
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