There’s little we can do about what sensors you choose…
That said, if you’re powering the Photon over USB, try hooking it up to the Vin pin. There should be around 4.8V on there, which I think suffices.
If not, you could ‘hack’ your sensor by bypassing the regulator, as is shown here
Here is the design I used to make sure it worked. It will actually require 6V. The set up here would work, but I also have a raspberry Pi, and Arduino. Thanks @Moors7 for confirming this.
I recently got started with the Photon via the Particle io maker kit from Adafruit. I found this post while researching topics about the PIR sensor.@christine suggested IFTTT and I just wanted to expand on that comment. I used this guide: http://diotlabs.daraghbyrne.me/7-communicating-events/pir/ to step 4, then created an IFTTT recipie to send a notification upon publish. There is also a schematic/diagram included in the guide.
IFTTT can be a little more sluggish than using Webhooks; works good enough for notifications, but I wouldn’t recommend using IFTTT via Do Button for lights and whatnot.