This bachelor’s thesis presents the hardware and software development of an embedded system that can be used in GPS based data logging and tracking applications. The major steps of designing the system are described in the thesis, such as the enumeration of the project’s goals and requirements, the formulation of the specifications, the drafting of the system’s hardware architecture, the selection of the hardware components, and the schematic and layout design. The process of assembling the hardware and fine-tuning its parameters is presented as well. The embedded software development is described in this thesis. The design procedure of a separate board capable of connecting to the main board is also covered.
The main goal of the development is to design a device capable of acquiring geographical location data with the aid of a global positioning system. Because of the wide availability of compatible devices and documentation, the device uses the GPS system developed and maintained by the USA. The wireless connectivity necessary for tracking applications is provided by a GSM modem. Thus, the device can be used for tracking purposes all over the world, using the network infrastructure of GSM operators. The GPRS connection capability of the device makes it possible to achieve internet connectivity over the GSM network.
The device is battery-operated to facilitate mobility. The widespread availability and standards compliance of Micro USB wall adapters with 5 V output makes them ideal to be used for charging the battery of the device. No other external component is required to charge the device as the battery charging circuit is integrated. The battery life is critical in a GPS based tracking system. Optimizing the system for minimal power consumption was of great importance during the design. This is achieved by the use of suitable microcontroller, the ability to power off the individual components and the inclusion of an accelerometer that is capable of waking the device when motion is detected.
The logged data is stored locally on a Micro SD card implementing the FAT file system. The location data is stored in the Keyhole Markup Language format designed by Google. This makes it possible to import the logs into Google Earth, providing good-looking presentation of the logs. The logging frequency can be configured, the interval can be time-based or distance-based.
Wireless connectivity with external modules is made possible by the use of a simple 2.4 GHz ISM band transceiver. This functionality is demonstrated by an external hardware module operated from a CR2032 lithium battery that contains an accelerometer. This module can be used to further extend the usability of the system for security applications.