Probably you have noticed that Arduino is spread worldwide. It would be ridiculous to see one manufacturer producing them. The Arduino group produces an original board that is named Arduino. This is their trademark. But being open source product, Arduino become popular in almost all workshops and so demand is enormous. Since building plans are public, other electronics manufacturers started building Arduino compatible boards. These are same Arduino boards, but with Arduino name and logo removed. Other than that is 100% compatible with standard Arduino that works with software tools, extensions, and modules. Arduino compatible Uno R3 Rev3 development board is one of the most known boards. Because this form factor is the first Arduino step into the community, it
Arduino is a well-known platform among electronics hobbyists because of its simplicity, robust and intuitive design and ease of use even for non-electronics enthusiasts. This time instead of introducing new PCB variants or different microcontrollers on board they made some significant upgrades in Arduino concept. New changes came with two new Arduino boards so-called Uno and Mega2560. Probably the most significant difference is USB to serial converter. They decided to replace seemed to be hard positioned FTDI chip FT232RL with microcontroller Atmega8U2 that has hardware USB interface. With this upgrade, the Arduino board become much more flexible as microcontroller driver can be configured to be more than simple USB to serial converter. It also can convert Arduino to standard keyboard, mouse, MIDI and mass storage device. So, there are much more ways to use Arduino now. But this is not over yet. Arduino decided to change bootloader too with new Optiboot firmware that brings some improvements as well. New bootloader occupies 1.5kB less code space leaving it for applications and loads firmware to flash faster.