Development of Remote Motion Detection System

Abstract

This thesis outlines the development steps of building a wireless embedded system. The objective of this thesis was to find out if it is possible to develop and manufacture a motion detection system with separate units for detecting motion and alerting the user. The system is intended to work as an indirect doorbell, where a motion sensor is used to detect the presence of a human. Commercial solutions already exist but they lack customizability, which is what the system in this thesis is designed to address.

This thesis describes the thought process taken at each development step with a focus on the specific minor details. It is not a guide, but it rather describes and justifies the choices made. A key takeaway of this thesis is that embedded systems development is extremely detail oriented and it is often the smallest details that account for the success or failure of a development project.

The development process begins with the specification of the system, where realistic expectations for the system are presented. Next, electronic components and modules are chosen to attempt to meet these design specifications. After the important phase of component selection, the components are grouped together and placed in a schematic. The connections between parts in the schematic are used to design a printed circuit board layout, based on which the board can be manufactured. After the circuit board is manufactured, a case can be designed and manufactured to protect the board from damage during programming and testing. The manufacturing of the circuit board also allows for the microcontroller on the board to be programmed and its functionality validated. The system is now functional and can be tested and the results can be compared against the specifications set at the beginning of the process. In product development, the design would be iterated upon, but the scope of this thesis limits the development process to a single iteration.

The end result of the development presented in this thesis yielded a functional system, which partially met the design specifications. The system achieved its design goals in terms of battery life and robustness of the wireless system, whereas the wireless range and motion sensor require further development. The experimental use of a new type of motion sensor ended up being impractical for this application. The sensor provided false positives based on environmental factors, such as rain and heavy wind. Potential solutions to these shortcomings could be the use of external antennas and the use of a different type of motion sensor.