A Low-Cost Wireless Photovoltaic Device Measurement System

This paper presents the development of an affordable wireless current-voltage (I-V) characterization system based on a low-cost Wi-Fi enabled microcontroller unit (MCU). The prototype instrumentation uses a low-power Wi-Fi SoC equipped with a 32-bit RISC processor. A supercapacitor (SC) with low ESR is used as the load. When connected across a solar cell, the supercapacitor charges and its terminal voltage and current are measured using a 16-bit I²C current/voltage/power sense module. The measured current-voltage (I-V) data are sent over to the host computer over the Wi-Fi hotspot created by the MCU and the acquired experimental results are displayed on a custom-built graphical user interface (GUI) in real time. The developed GUI software allows the user to easily control the experiment. It can trace the I-V/P-V curve of a solar cell and estimate its photovoltaic performance parameters by automatically analyzing the data in less than 30 seconds. The system can be powered using a 5V USB wall charger or a portable battery power bank which can facilitate remote characterization of photovoltaic devices. The entire system can be built in less than 50 USD using off-the-shelf parts.