Hi Gimball - great to hear you have started building one of the projects in the book. However, it sounds like you’re using your own PiR sensor while you’re waiting for the SensorHub to arrive. Is that right? If so, depending on the type of PiR sensor you are using, it can connect to the Pi’s GPIO pins differently. You would also need to verify when the current pull is up or down. It might also require additional wiring, which is why I recommended the SensorHub as it helps to abstract all this detail via a library that makes polling the sensor status trivial. However, if you are still interested in the custom PiR approach, take a look at this Medium.com article that might help:

Good luck with your Portable Pi Projects!