Emergency alert and evacuation management systems (EAEMS), if present in buildings, significantly reduce people evacuation times in emergencies (in comparison with static routes pointers), and they can thus reduce the number of victims. The paper describes an approach to the EAEMS creation that meets the requirements of a reasonable cost. State-of-the-art of microelectronics and computing machinery, as well as the accumulated global theoretical evidence make it possible to create the most effective EAEMS. Unfortunately, the cost of such systems is not affordable to be introduced everywhere in operation. An important and very expensive part of such systems are sensors of people gathering density in the building. Their absence causes the use of appropriate computer models to predict the dynamics of the human flow density. In turn, the use of very accurate models also make system more expensive due to the required computing resources. Therefore, the main objective of this work is the search for applicable mathematical model, as well as implementing its program algorithm, which would allow to construct EAEMS using cheap microelectronic elements. The choice is made on the flow model of the foot traffic in the building, using experimentally determined flow rate depending on the density of the people. It is shown that the program implementation of the selected model which represents the building in the form of a computational grid produces results, which consistent with the results presented in the works of other groups who used other, more accurate models. Unfortunately, as shown in the paper, this software implementation of model does not allow to produce real-time calculations on the basis of the cheap single-board computers (for example, Raspberry Pi). Replacing the spatial representation of the building from a grid to a weighted bipartite graph reduces the computational time dozens of times, and thus makes it possible to use the single-board computers. Testing of the graph based implementation of the model shows adequate results that are comparable with the results of more accurate models and algorithms consuming more computing resources. Thus, it is concluded that affordable EAEMS can be constructed on the basis of inexpensive microelectronics with the application of appropriate computer model of the people movement in the building.