Before Arduino, the domain of microcontroller-based applications was limited to hardware programmers. Arduino made it simple for developers that came from other software fields and even for the non-coding community to develop microcontroller-based hardware applications. Arduino consists of a simple hardware design with a microcontroller and I/O pins to interface external devices. If one can write an Arduino sketch that can transfer the control of the microcontroller and these pins to an external software mechanism, then it will reduce one's efforts to upload Arduino sketches for every modification. This process can be performed by developing such an Arduino program that can then be controlled using a serial port. There exists a protocol called Firmata, which does exactly that.