The user interface will consist of a single button and several LEDs or a RGB LED through which all user communication will occur. An overview of the proposed system states and transitions is given below. Pressing the button will wake the device up from sleep and put it into operating mode. If the button is pressed and released in the operating mode, a waypoint of
the current position is recorded into the log. Pressing the button for 3 seconds will put the device to sleep. The device will also go to sleep when in the same location for 5 minutes. Data logging will stop when the device is connected to a computer or GPS lock is lost. The GPS receiver will stay powered up while the device is in the sleep state to maintain signal lock until the battery level gets critical. The SDCard will be powered down during sleep. Coming out of sleep mode will create a new log file. A schematic of the prototype hardware is presented below and include the PIC, GPS interface, SDCard Interface, USB, Voltage regulation and User interface. Missing from this version of the prototype is a battery, voltage monitoring and charging circuit. The initial software will consist of the data logging part only, to assess the viability of the project and to provide data for some of the requirements. Battery monitoring will be implemented but not control anything to provide better power usage figures. The software will be written in the following order: Each section will be tested and confirmed working before the next section is started on. Once all sections are complete, the prototype will be used to gather power usage in order to design the final system and battery requirements.