“An Arduino based alert and logging system, including portable receivers for tracking 40 room doorway motion sensors in an aged care home.
The project goal was to alert care staff to residents with dementia wandering into other peoples rooms, particularly when the other person was in bed at night. The system has a base unit at the nurses desk that featured a real time clock, sd card logger, display and buzzer, as well as buttons and menu system for configuration. There is also several handheld rechargeable receivers that have a display and buzzer that care staff can carry for when not near the nurses desk base. This project has been closed source until now, for the hackaday 2023 prize, I want to share this for anyone that can find it useful. The initial build out is done and working, if their was interest it could be commercialized/reproduced. It was a time when wifi modules where $30+ dollars each ! And not feasible for a low budget project that at it conception needed ~40 nodes. So it was built with NRF24 modules. If i built it again, I would use wifi modules.
Originally the plan was to use a magnetic reed sensor and battery powered arduino 328 with NRF24 on each doorway to monitor the doors opening and closing, and progress was made in this direction including designing and having printed my first pcb, but luckily it was found that there was already a (very discreet) motion sensor in the roof overlooking every door way, its just the logic for the existing bed sensor system that it was connected to prevented it from raising an alert if the resident was still in bed, (ie from another resident else walking into the room).
There were several key advantages to using a roof mounter PIR sensor:
It detected door way activity even if the door was open
There were no batteries to go flat
Less radio units in the network meant much simpler topology
Less hardware components
No need to install anything on the door and doorway.
So permission was obtained from the existing bed sensor system installer and the facility management to disconnect all the existing motion sensors from the bed sensor system and wire them into one of 5 arduino/rf24 hubs in the roof which relayed motion events to the base unit at the nurses desk.”