**1. Introduction**

Rapid development of electronic, computer and information technologies has enabled design and implementation of different types of so called embedded systems used for many different needs and purposes, for many practical applications. Such systems are designed and implemented to be maximally adapted to concrete application and to efficiently perform specific needed function. Also, such systems should be as simple as possible, with as much small dimensions as possible, as cheaper as possible and to consume as little energy as possible. Those systems are always specialized and optimized systems for some specific purpose and are used in almost all areas of human activities [1–4].

Different hardware and software solutions, different hardware and software platforms, can be used for development, design and implementation of such embedded systems. Those are mostly microprocessor-based solutions and platforms. What practical solution will be used primarily depends on specific requirements that such system should satisfy, in accordance with concrete need. Specially designed solutions and specially designed platforms are most often used for such purposes [1–4]. But, it can be shown that in many practical needs it is much more convenient and better to use so called open source hardware and software solutions, platforms of open source type [1–10].

Possible ways of design, implementation and application of embedded systems based on open source microcomputer hardware and software platforms are proposed and described here. Using open source hardware and software microcomputer-based technologies for design and implementation of embedded systems in many practical needs and applications is proposed. Main possibilities and advantages of such embedded systems are considered and described. Two such practically designed and implemented systems that perform appropriate data acquisition and control are presented and described. The systems hardware was implemented using open source microcomputer boards, appropriate sensors, actuators and additional electronics. The systems software was implemented using open source tools and programs and LINUX operating system.

The remainder of this chapter is organized in a following way. Section 2 considers basic concepts of embedded systems, main characteristics, way for design and motivation for practical application and implementation of such systems. Section 3 describes main concepts of proposed embedded systems design and implementation based on open source platforms. This section proposes way of design and implementation of open source hardware and software-based microprocessor embedded systems as specialized systems optimized for concrete user need. It also describes advantages of such design and implementation. Section 4 describes design of one practically implemented open source-based microprocessor embedded system for user identification in access to objects using mobile phone, as specialized systems optimized for user need. Section 5 shows and in more details describes design and implementation of one such based SCADA and RFID embedded system for industrial process control application, implemented using LINUX platform. Finally, a short summary and conclusions are given in Section 6.
