Research, approach and build prototype of solar harvesting hybrid smartwatch

Abstract

Hybrid Smartwatch has a big issue with short battery life because it only can work from six months to one year. Regular battery replacement may make users inconvenient when they have to send their smartwatches to the customer service department. Furthermore, a large number of wasted batteries can cause serious pollution, especially land and water pollution. Using solar energy to charge the battery instead of traditional charging can help Hybrid Smartwatch operate longer that makes more comfortable for customers. We replace resistors with different values to program the desired voltage limits in BQ25570-EVM206. Then we draw schematic and PCB for BQ25570 prototype. Build a simple algorithm to calculate approximately charging current according to lux and charging current according area by using Anaconda (Python 3.6). Use Net Beans 8.2 IDE to build an application for calculating the charging current. To charge rechargeable battery LIR2025 with VBAT = VSTOR = 4.2V and operating Hybrid Smartwatch SE1 with V=3.0V, we complete PCBA with variable resistors that can adjust the expected output voltage likes VBAT, VSTOR, VOUT. Interface for calculating the charging current to battery depended on users’ activities and weather conditions over day time were carried out.