unsurv offline is a privacy friendly, small and lightweight PCB (45 mm x 32 mm) based on an ESP32 featuring a high quality GNSS receiver, accelerometer, and NFC capabilities. Using a combination of onboard features and OpenStreetMap (OSM) data, unsurv offline helps you collect and analyze location data in a privacy-friendly way. Originally conceived to better understand offline video surveillance, this fully open source project is here to help you find and develop a variety of custom use cases.