I'm working on a project to use PIR sensor to save on electricity bill in a university, almost a fresh graduate in Electronics Eng.
Load is Fluorescent tubes 44w each via ballast,there will be between 16-36 lamps available per relay, the idea is to control them using:
- inexpensive PIR sensor
- 5v Power supply,
Few problems occurred: First, there will be a lot of wirings and bigger chance of something going wrong in the setup, especially since each room can have a separate power supply, or multiple rooms sharing a power supply.
Second, Fluorescent lamps as I read, can take up to 100 times the rated current at start, our relay for now is a 30A relay SLA-5vdc-SL-A module, current for some rooms is calculated to be 7A, I've read about SSR, it can solve the problem, but are they safe (I mean the ones made in China), what could go wrong?
Third, for the power supply, many options are available, but the place this will be installed is critical (a university), so safety is a huge concern, system running 24/7 but at low current, maximum per room 500mA, PS can be connected to up to four rooms together, or one per room.
Is the project on the right path at least? any suggestions?