The study is devoted to the complete design, assembly, and detailed verification of the functionality of the barrier based on ultrasonic technology for the detection of different intruders in an entrance area. This barrier is used in the perimeter and shell protection of guarded areas. The construction of the barrier, the selection of the most suitable sensors, the design of the transmitting and receiving parts, analog and digital processing, a modern microprocessor system, and the complete assembly and testing of the system’s response to various types of intruder are accurately described here. The system can not only evaluate the intruder presence, but also determine the type, such as a person, child, animal, and flying object, which gives the barrier a certain intelligence. Economical and easily available components on the market, as well as modern electronic devices, are chosen in the design. Directly, the microprocessor system allows the communication and transmission of the information about the character of the intruder, not only via universal serial bus but also via several wireless technologies. These technologies are Bluetooth, Bluetooth low energy, and also Wi-Fi. With these technologies, the algorithm in the microprocessor system can also be modified. The designed device represents a certain prototype that can be improved in the future with increasingly modern technologies.