In many microcontroller-based projects, you may need to communicate with PC. There are several ways to do this like RS232 COM port, USB port, parallel port, WIFI, Bluetooth, etc. You cannot directly connect computer to your microprocessor, you need wireless modules for WIFI and Bluetooth, voltage convertors for RS232 and parallel port and a protocol engine for USB. Here I am going to show you how to make a simple and compact RS232 voltage convertor for your projects that gets its power from the PC. If you are interested in making one yourself follow me.