Energy harvesting through piezoelectric and triboelectric methods have been explored as a prospective solution to gather the irregular mechanical energy into electricity used in our daily life. These techniques were able to power the LEDs, active sensors, and other low-powered consumption devices. Among them, the active sensors have successfully analyzed the object motions, for instance, muscle-driven nanogenerator, wind-velocity detector, and humanï¿½machine interfacing devices. Today, mobile technologies, especially personal and mobile electronics, are becoming very popular. However, it is important to address the electric-waste issue (ie., non-recyclable garbage that contains toxic heavy metals such as lead.) by adoption of miniaturized energy-harvesting and/or self-powered systems. Thus, lead-free electronic materials are a topic of intense interest. In this report, we will demonstrate a flexible nanogenerator made from lead-free nanomaterials, for instance, ZnS, TeO2, and ZnSnO3 etc. It can be further applied on the wrist-worn devices for detecting the human pulse, tiny physical motions, and touchless control of smart devices.