This project uses the same hardware as Adafruit's Raspberry Pi Lesson 12. Sensing Movement, minus a breadboard and the Pi Cobbler. On a Pi model B with the Pi Cobbler, that setup looks like this:
Instead, I did the following (which should work with a B+ or a Pi 2):
From the PIR sensor to the Pi, connect:
- Power (red wire) → 5V
- GND (black wire) → GND
- Signal (yellow wire) → GPIO 18
From the door switch to the Pi, connect one end to a GND pin and the other to GPIO 23.