Passive Infrared (PIR) Motion Sensor
I am working on something similar and for Private wireless and secure network you should use Xbee device https://store.ncd.io/product/zigbee-mesh-xbee-pro-long-range-wireless-mesh-communications-module-with-integrated-antenna/ connection which is easy to be compatible with sensor as Router and transmits the wireless signal, which will be received by another Zigbee device connected to arduino and acts as coordinator.

Hope this will be helpful for your making wireless connection between sensor and Development boards