Essay --

The 3G+GPS shield uses the 3G module, SIM5218E from SIMCOM, which enables the connectivity to high speed WCDMA and HSPA cellular networks. It is a single board which can handle high speed wireless communication. The 3G module has an internal GPS with the help of which it is possible to locate the device outdoors as well as indoors. It combines the standard NMEA frames with mobile cell ID triangulation for accuracy and uses both assisted-mobile (A-GPS) and mobile-based (S-GPS) modes. A video camera can be connected to the shield which enables recording photo and video in high resolution (640x480). It is also possible to connect a microphone to the module and a SD socket to save directly all the data coming from the 3G network or recorded from the video camera. Since the 3G+GPS shield supports the above mentioned features with all the hardware on board, it became the first choice for the implementation of the prototype. Described below are the important components of the 3G+GPS shield that we have used. 3.1.1 Hardware 3.1.1.1 3G Module (SIM5218E) Figure ‎3 2: SIM5218E Sim5218E is a quad-band GSM/GPRS/EDGE and UMTS engine that works on frequencies of GSM 850 MHz, EGSM 900 MHz, DCS 1800 MHz, PCS 1900 MHz, and WCDMA 2100M/1900M/900M [28]. Sim5218E provides interfaces for Serial communication, GPS, Camera, USIM Card as well as an audio interface. These are described briefly below. Detailed information about these is present in the â€Å"Hardware Design† document of SIM5218E [29]. Serial interface Sim5218E has an asynchronous serial port. Sim5218E is designed as a Data Connection Equipment. It can be connected to any Data Terminal Equipment using standard DCE-DTE connection. Serial port can be used for sending AT commands ... ...verage problems are experienced, then two antennas are used, where the second antenna is connected to the sub-antenna connector. 3.1.1.2 Electret Microphone We have used electret microphone for the prototype. It is a small microphone useful in acoustic and audio applications. Figure ‎3 3: Electret Microphone 3.1.1.3 Camera The camera used for the prototype is a VGA Sensor Camera module. This camera is a very compact size. It uses a GC0309 CMOS sensor. It is 0.3MP (VGA) camera with a maximum resolution of 640 x 480 dpi. Figure ‎3 4: VGA Sensor Camera 3.1.1.4 Arduino Mega 2560 Figure ‎3 5: Arduino Mega 2560 Arduino Mega 2560 is a microcontroller board based on the ATmega2560. It has 4 UARTs (hardware serial ports), which will be very useful in interfacing various components. It has a 16MHz crystal oscillator with a flash memory of 256KB and SRAM of 8KB.