Experimental Results for Energy Harvesting by Exploiting Inherent Inadequacies of Sampling Process for IoT Applications

Senor nodes either deployed for environment monitoring or health monitoring are battery operated, and thus energy constrained. This paper proposes a novel method for energy harvesting for the Internet of things (IoT) based applications by exploiting the inherent inadequacies of the sampling process. The sensor nodes generate a continuous-time signal corresponding to the sensed parameters, which sampled and digitized for further processing. However, the traditional sampling process discarded most of the input signal energy, which could be harvested to supplement the sensor node itself. The sampling interval (i.e., the duration between two samples) of the sampling process, is composed of acquisition and hold time. During acquisition time, the continuous-time input signal is connected to a capacitor for acquiring the input signal value, while in hold time, the capacitor holds the acquired value and disconnects from the input signal. Therefore, during the hold time, the input signal energy is wasted, making the overall sampling process inadequate. This paper overcomes these inadequacies by modifying the circuitry of the sampling process during the hold time. It thus harvests the energy from the input signal obtained through a sensing element without affecting the overall performance of the system. To validate the proposed method, a hardware setup has been designed to sample and harvest the energy for both the environment as well as health monitoring application.