1. Indoor positioning
The Zigbee positioning nodes are distributed at home, and the positioning of the elderly can be realized by the wristband (embedded with the Zigbee module); and the location can be displayed on the platform and the mobile phone app, thus realizing the indoor positioning that cannot be realized by the current mobile phone App. Rescuer can find the elderly quickly and save valuable rescue time.
If the Zigbee positioning nodes are distributed in the building, that is, when there are many families implemented the system, the three-dimensional positioning of the elderly can be realized, and when the rescue is under way, not only rapid positioning but also an algorithm can be applied to propose a rescue path in the community to saves precious time for rescue and further improves the efficiency of rescue.

2. Authorization for door lock
We modified a common door lock to add a Zigbee module and electromagnetic mechanism, so that the door lock can be opened remotely. When the old man has an emergency, the rescuer can unlock the door after receiving the authorization to unlock the door and save rescue time.