Development of a portable power supply displayed through web browser

Abstract

The purpose of this research is to DC power supply with selectable voltage both from machine and web browser. It is Control by Node MCU V.2 microcontroller, choose from 4 voltage ranges is 3V, 5V, 8V, and 12V. with an error is 4.92% compared to Analog Multimeter brand SUNWA model YX360TRF, maximum current 1.00 A, voltage display is on a 0.96 inch OLED screen and a web browser screen. It is  Portable power supply with a wireless charging system, able to alert the battery is dead and the battery is full via the LINE application.