Hi everyone...so i was thinking is it possible to program arduino to act like everyday usb memory stick.
I would use SD breakuot board ( so the whole memory for saving data would be on SD card ). When i connect arduino to PC over usb can i copy and delete files from PC to SD card back and forward like in memory stick?
Thank you 
Please help anyone...i know it looks stupid but i have an idea i this would be a great starting point....
Perhaps you should watch this thread for developments:- Connecting SD Card to USB port through Arduino
You need one of the Arduinos with a native USB port: Leonardo, Micro, Due or Teensy.
But the code to act as a mass-storage device is surprisingly complex. It may even be too big to fit onto a Leonardo or Micro. I've never seen anyone do it. It would be great if you could as there's a lot of projects that want to log data to an SD card and don't want to pull it out of the Arduino to read it.