Why not use the onboard WiFi adapter on the Raspberry Pi3 B ?

On the sensor topic . Why not go with a Microwave Sensor. Search posts by @fozzie as he has just installed one and likes it alot!

I searched for the thread for you and here it is https://forum.magicmirror.builders/topic/11704/update-replaced-my-pir-sensor-with-a-doppler-microwave-sensor/12