Light Rail Camera - an EMC-assessment

Sammanfattning: When installing multiple security cameras the cable management can be a struggle. Historically cameras need one cable for power and one for communication, however, advancements in power over ethernet have reduced the number of cables down to one. Installations can still prove difficult and costly as they have to be done by professionals, especially when setting up a large number of cameras. Once they are in place they cannot be easily moved either. Wireless cameras could solve some of these issues but the fact remains that each and every camera needs a power cable. A wireless infrastructure capable of handling all the cameras also has to be set up which can be costly. This thesis aims to provide a possible solution to these problems by combining the cameras with light rail infrastructure using powerline communication. This was realized by building a proof of concept prototype that enables a camera to be attached to a light rail and have both its power and communication fed to it through the rail itself with no additional cables needed. Many different solutions on how to realize this goal was investigated throughout the report. It was known that sending high-frequency communication on exposed wires in the light rail might lead to issues with EMC, electromagnetic compatibility. This was taken into careful consideration. The final prototype was tested for electromagnetic emissions and efforts to lower them were also made. The results clearly show that it is possible to send both communication and power on a light rail to a camera. The implementation in this thesis did indicate that EMI is indeed a problem, however, it was also demonstrated that there might be ways of solving them.