Arduino is an open-source computer hardware and software company, project and user community that designs and manufactures microcontroller-based kits for building digital devices and interactive objects that can sense and control objects in the physical world.
The project is based on microcontroller board designs, manufactured by several vendors, using various microcontrollers. These systems provide sets of digital and analog I/O pins that can be interfaced to various expansion boards ("shields") and other circuits. The boards feature serial communications interfaces, including USB on some models, for loading programs from personal computers. For programming the microcontrollers, the Arduino project provides an integrated development environment (IDE) based on the Processing project, which includes support for the C and C++ programming languages.
The first Arduino was introduced in 2005, aiming to provide an inexpensive and easy way for novices and professionals to create devices that interact with their environment using sensors and actuators. Common examples of such devices intended for beginner hobbyists include simple robots, thermostats, and motion detectors.
Arduino boards are available commercially in preassembled form, or as do-it-yourself kits. The hardware design specifications are openly available, allowing the Arduino boards to be manufactured by anyone. Adafruit Industries estimated in mid-2011 that over 300,000 official Arduinos had been commercially produced, and in 2013 that 700,000 official boards were in users' hands.
Arduino has various types of hardware:
- Really Bare Bones Board--easy to construct Arduino engineering project for newbies. 
- USB to TTL serial adapter--adapter used along with RBB to upload code.
- Arduino Uno
- Arduino Nano
- Arduino Pro
- Arduino Shield
- Arduino Micro
- More products
- ↑ Arduino. "FAQs." accessdate 2015. https://www.arduino.cc/en/Main/FAQ
- ↑ Arduino. "RBBB instructions" Accessdate 2015.
- ↑ Modern Device.com. "BUB instructions" Accessdate 2015.