Android, an operating system developed by Google for smartphones, tablets and such type of touchscreen phones. Android app is a software running on Android platform. Typically an app is designed for specific purpose on Android platform such as smartphones and tablets. In this work a designing and implementing process of an Android based spy robot is described. An Android based application, RC Bluetooth controller is used to control in this spy robot. This robot can be controlled with the help an app of Android phones. Arduino based microcontroller is used for instruction processing and giving proper instructions. Bluetooth technology is used to interface between Arduino and Android. A hand for collecting and holding objects and a camera for live video steaming is used to observe any object & movement of robot. This robot can move to any place and perform smartly within Bluetooth network range.

This paper deals with the designing and implementation of microcontroller based security system to alert when unauthorized persons try to enter in a home. The first phase of security was implemented using a GSM module to send alert message (SMS). To make the system robust additional layers of security has been incorporated by including security devices such as android based door password, manual keyboard to open the door, PIR motion to detect unauthorized person in the home, rotating ultrasonic sensor by servo motor to active the camera to capture image and RF transceiver to produce voice signal to alert people outside the home. The system's main hardware was designed by Arduino based microcontroller ATmega328. Arduino ISP was used for system designing and Arduino serial monitor is used to test the GSM module. The implemented system was seen to perform well.

A single layer substrate compact dual band rectangular micro-strip patch antenna with transmission line feeding is designed for Wireless Local Area Networks (WLAN) implementation. The desired antenna consists of a rectangular patch having two I-slots and a dielectric material with dielectric constant of 2.4. The use of cavity model with transmission line feed has the favor of low profile, high gain and wide bandwidth of the antenna. The antenna has overall size of 46.9 mm by 38.01 mm and gives bandwidth of about 90 MHz at resonance frequency of 2.45 GHz and that of 115 MHz at 4.1 GHz frequency with Defected Ground Structure (DGS). The antenna with DGS has return losses -21.25 dB at 2.45 GHz and -27.5 dB at 4.1 GHz where the gains are 6.70 dB for 2.45 GHz and 6.80 dB for 4.1 GHz. Finally the designed antenna has been simulated using Computer Simulation Technology (CST) microwave studio 2009 and it is comparable with manual computation results which are found to be suitable for WLAN applications.

A dual band linear polarized micro-strip antenna is designed and simulated to obtain electronic circuit miniaturization of an antenna in high speed wireless local area networks (IEEE 802.11a standard). The proposed antenna contains a substrate layer (FR-4 lossy) with a dielectric constant of 4.4 and there is a circular patch on the upper layer of the substrate. The coaxial probe feed is used to excite the desired antenna which reduces the spurious radiation and hence obtained good efficiency. It is shown that using cavity model 20% excess bandwidth can be achieved while maintaining the lower size of the antenna. An 'E' shaped slot is introduced in the radiating patch to obtain dual band resonance frequency with maximum current distribution on the surface. Finally the simulated results using Computer Simulation Technology (CST) microwave studio 2009 in this design is compared with manual computation results which are found to be suitable for WLAN applications.