Here’s how to send data from your PC to an Arduino. This project is a simple clock that shows the PC’s time and date on a 16×2 character LCD attached to an Arduino. We use Java to write a minimalist GUI that lets the user select the Arduino’s COM port, and then the PC just streams the current date and time to the Arduino over USB.
Software – http://farrellf.com/arduino/LcdClock.java
Firmware – http://farrellf.com/arduino/LcdClockFirmware.ino
IMPORTANT: If you have not seen my previous video on serial communication, check it out. That video covers all of the basics, and shows how to install all of the software you need.