Highly miniaturized tracking devices communicate via existing communication architecture, such as smartphone, smartwatch or fitness wearable. Devices of minimal size, with low power consumption and compelling economics, focus on the sensory collection of diverse data from the wearer, such as people, animals, or tools. This data is securely encrypted by the tracking device. Based on BLE, the collected data is transmitted to the cloud by reachable smart devices, with an existing internet connection, using the mailbox principle (soft gateway application). The transmitter is denied access to the data. The focused device architecture allows, for example, discrete installation in smaller hand tools and ensures, through energy-efficient operation, a long, self-sufficient operation time. Optionally, this can be significantly extended by harvesting.