The design and implementation of a microcontroller based voice activated wireless automation
system is presented in [21]. The user speaks the voice commands through a microphone, which is
processed and sent wirelessly via radio frequency (RF) link to the main control receiver unit.
Voice recognition module is used to extract the features of the voice command. This extracted
signal is than processed by the microcontroller to perform the desired action. The drawback is that
the system can only be controlled from within the RF range. Reference [22] also presents a voice
activated smart home automation system. This system provides graphical user interface (GUI)
using Microsoft Visual Basic software hosted by a PC, and uses Microsoft Speech Recognition
engine. The signal is than transmitted via RF link to the microcontroller to which the home
appliances are interfaced. Again a PC is used that account for an increased cost and power
consumption.