This diploma thesis deals with covers design and realisation of device for multipoint temperature measuring in fotovoltaic systems. As a controlling microcomputer is used Atmel ATMega128L, temperature sensors are realised by DS18S20 digital thermometers, connected via 1-wire bus. System can read temperature from x temperature sensors, includes memory for measured data, real time clock and display with buttons for basic user control. Temperatures are measured periodically, values are stored into internal memory and showed on display.Measured data can also be transferred via seriál bus to clinent PC. Device is projected as a battery-operated compact tool. The final realization is made with respect to minimal system requirements and to possible future extensibility for wider usage spectrum.

The 1-wire bus is a communication bus system which is designed to provide data, signals and power over a single signal with low data rates, a high resolution and a long range. It is typically used to communicate with small inexpensive devices, as temperature sensors, which is worked as a slave with the master computer (PC). The 1-wire bus system provides the sufficient control and operation signal, a unique ID serial number of each sensor and it supports multiple temperature sensors by a driving power (Parasite Power) on single line. On the 1-Wire bus system, temperature sensors are supplied by two types of power supplies, external Power supply and Parasitic Power. The aim of this project is to program the microprocessor (Arduino) by using Arduino programming language to work as a temperature sensor type DS18B20 and also as a slave on the 1-Wire bus system. This report explains the 1-Wire bus system techniques and how the communication is achieved between the master and the slave (sensors) to measure the temperature values. The measured temperature values are collected from the output of each active sensor on the 1-Wire bus. These data are displayed by the personal computer (PC) which is worked as a master on the 1-Wire bus, and the data are represent the measured temperature values from twelve active sensors on the bus system. In this thesis, the temperature values from the 12 active sensors can be read and displayed on the master (PC) by using the following programs: Open Logger One Wire (OLOW) program, One Wire Viewer, DigiTemp and OWFS and I validated all the temperature values from these active sensors which are read and monitored by the drive bus programs. The comparison is done among the measured temperature values to see if the active sensors are given accurate temperature values with different drive bus programs. The project shows that the sensors can be connected in a network with the master, by using 1-Wire bus techniques. This thesis will be used by Karolinska University Hospital, and it can also be developed for different requirements in the future.

This thesis deals with design and implementation of a versatile control unit, which is primarily designed for control of solar collectors. It describes the various stages of design. First, the system of solar collectors is introduced. Its input-output parts are analyzed and the requirements are determined for the control unit. The characteristics of temperature sensors are examined, the work deals with continuous variable speed circulators. The following part is dedicated to hardware and software implementation of the objectives of the work. The boards were designed in Eagle design environment, the firmware was written in C programming language. In conclusion, the evaluation of the results of the proposed system and possible ways of its further development are discussed. The versatile control unit can be deployed in practice realistically.