-Arduino is a project of many collaborators.
Started with the (popular) "UNO" , nowadays  there are  various models, with extended memory capacity etc...
-Each (Arduino)PCB contains a microcontroller and peripherals.
-Simply by the use of dedicated software, all kind of projects can be made .
-This (free acces) software is stored in hundred of different Libraries.
-As example:By using the specific "Library" ,the Arduino Processor  controls a "BMP280"  to develop a complete  Barometric, Pressure & Altitude gauge

-I designed and build several projects : timer,talking barometer, Morse Beacon, Digital Variable Freq. Oscillators (VFO) ,motor controller etc ...

Detailed information can be found at www.arduino.cc