I have seen a lot of thing about ardunio. but i have no idea what it is! can someone help me?
Arduino is an open-source project that created microcontroller-based kits for building digital devices and interactive objects that can sense and control physical devices. http://www.pcworld.com/article/239454/geek_101_what_is_arduino.html
No, it's not deja-vue...https://www.instructables.com/tag/?sort=none&limit%3Atype%3Aquestion=on&q=what+is+arduino L