Smart device control system based on GUI App provides a modern alternative to the traditional key and access is generally managed by an online service. Typically the electrical devices themselves do not connect to the communication network directly, but communicate with a Smartphone app, which in turn talks to the online service. This system illustrates a non-traditional approach to system control focused on speech recognition using mobile apps and wireless application protocol. In all ways, life is becoming simple and simple with advancement in technology. New research is currently going on in every field to boost device efficiency and to make work simpler than previous ones. Automatic systems are favored over manual systems in today's world. One of them is speech recognition based interface control. It consists of a BT (Bluetooth) control board, a relay circuit and a Smartphone app. This allows devices to be operated by users by just sitting in one position. A significant advantage of this method is the control of machines, i.e. making them on and off as per user requirements. This user can save as well as discourage excessive use of energy by using it. Device access is restricted to a single user, so that protection is not compromised. The smart phone touch to text generator APP is used to generate the text character. The pre-stored character in controller memory is compared with present text character. The authentication text is generated by the APP if compared text is valid. The text of the APP is transmitted from smart phone to microcontroller through Bluetooth device (Wireless application protocol). The controller is received the text from Bluetooth device and compare the text with predefined text parameter. The controller is enables the relay switching unit for turn on and off the electrical appliances.