This is my project to a all in one sensor, it contains interface to:
Controlled by a Atmega328p-au and NRF24L01 SMD
Powered By 3 AA batteries, split in 3v and 4.5v, or if you prefere only 2 AA (3v). You can set the power jumper to safeguard the RF Radio. This interface is the best way to control a PIR sensor and ensure that the power feed to the PIR is inside acceptable range. (please see https://forum.mysensors.org/topic/6511/hc-sr501-3-3v-randomly-sends-tripped-when-radio-is-on/ ), see images to more information.
Work still in process... comments and recommendations are welcome.