Human bodies are very good heat sources with peak emission wavelength of about 9μm. We use pyroelectric detectors that are differential in nature to detect human motion by their heat emissions. Coded Fresnel lens arrays create boundaries in space which helps to localize the human motion as well as classification. We design and implement a low-cost biometric tracking system using off-the-shelf components. We demonstrate tracking and classification using sensor clusters of dual-element pyroelectric detectors with coded Fresnel lens arrays.