Design and implemention of multipoint data collection and wireless tranmission system for terrain applications

It is a serious problem to provide system control and follow-up in areas that are difficult to reach and where there is no necessary infrastructure. Wireless communication systems are preferred to solve this problem. Some of the most important reasons for this are low cost, easy to install, and minimal maintenance requirements. These systems usually consist of a few central stations and their secondary stations. In this thesis, Wireless Sensor Network (WSN) prototype consisting of total 4 units (1 Central and 3 Secondary) has been designed and manufactured. Sensor units communicate using wireless communication and have capacity to read 4 analog voltage values in real time mode. They can be places in both open and closed areas. The system uses the open ISM band frequencies (2.4 - 2.5 GHz) for wireless communication. The nrf24l01 module, which working range includes this band and allows to make communication channel settings such as frequency, communication speed, output power, is used as a transceiver. This unit reads the numerical data from the processor by SPI communication and packs them into a suitable packages ready to be sent. This unit supports up to 1000 meters of communication and this property has been successfully tested. The sensor units use a microcontroller from Atmel which houses a built-in Analogue to Digital Converter (ADC) as a processor. Thanks to the internal ADC, additional circuitry is not required for voltage sampling and both power and size are saved. Apart from this, there are 4 rechargeable AA batteries in each unit. In the central station, there is a memory card with the reader for reading out the received data and a time module for time synchronization. The received data are recorded in the 'text' file on the memory card together with the date and time data. Thanks to the modular structure, the central station can be connected to the user's computer at any time and the voltage values received from the sensor units can be monitored instantaneously by serial communication. For this purpose, the MATLAB user interface has been developed and tested successfully. Finally, the system has been tested in different terrestrial environments under actual working conditions and it has been observed that the system works as expected.