Design of a low cost GSM based embedded system for preventing vehicle theft using AVR microcontroller

• 1.    Introduction

  In recent years, vehicle thefts are increasing at an alarming rate around the world. According to National Crime Information Center (NCIC), in 2006, 1,192,809 motor vehicles were reported stolen, the losses were 7.9$ billion [1]. People have started to use the theft preventing systems installed in their vehicles. The commercially available anti-theft vehicular systems are very expensive. Therefore in this paper we propose a simple low cost embedded system to serve this purpose. The embedded system block consist of an AVR microcontroller, GSM module, LCD, keypad, relay circuitry, power supply unit.

GSM (Global System for Mobile Communications, originally Groupe Spécial Mobile), is a standard developed by the European Telecommunications Standards Institute (ETSI) to describe the protocols for second-generation (2G) digital cellular networks used by mobile phones, first deployed in Finland in July 1991. As of 2014 it has become the default global standard for mobile communications – with over 90% market share, operating in over 219 countries and territories. The network structure of GSM is divided into a number of discrete sections as follows [7]:

• •    Base Station Subsystems (the base stations & their controllers).

• •    Network and Switching Subsystem (the part of the network most similar to a fixed network, sometimes just called the “core network”.

• •    GPRS Core Network (the optional part which allows packet-based Internet connections).

• •    Operations support system (OSS) (network maintenance).

• 2.    The designed embedded system

• A.    The AVR microcontroller

The heart of the system lies in the AVR microcontroller, which handles all signals. It is an 8-bit microcontroller which works on 16 MHz crystal frequency. The version of AVR we are using here is ATmega32 by atmel. The key features of ATmega32 are:

• •    High-performance, Low-power consumption.

• •    Advanced RISC architecture.

• •    High endurance non-volatile memory segments.

  

• •    JTAG (IEEE std. 1149.1 Compliant) interface.

The pin configuration of ATmega32 is shown below in Fig. 2.

• B.    The keypad

• C.    The display unit

• D.    The relay unit

The relay we are using here is driven by Power MOSFET (IRF830) and we apply the output of AVR microcontroller to the gate of MOSFET. The MOSFET is biased by 12V supply from the battery.

PDIP

Fig. 3. The Designed Keypad

• E.    The gsm module

  We are using SIM900A GSM module with GSM/GPRS which works on frequency 900/1800 MHz. The receiver (Rx) pin of GSM module is connected to Tx (pin 15) of microcontroller & transmit (Tx) pin of GSM module is connected to Rx (pin 14) of microcontroller. The default baud rate of both module & microcontroller is 9600. The GSM module communicates with the microcontroller serially as per UART (Universal Asynchronous Receive Transmit) protocol. The signal of module contains Data Bits: 8, Parity: none, Stop Bit: 1. The frequency & baud rate can be modified using AT command.

• 3.    The schematic simulated hardware design

• 4.    Conclusion

Fig. 4. Simulation Schematic of the embedded system