Quantity   Component name
1 × Raspberry Pi Model B is best because of multiple USB ports. Memory usage is not super high so it would probably still work on a model A.
1 × Playstation 3 Eye Camera Any USB microphone will work, but this one has a nice microphone built to capture audio in a room.
1 × Mini Thermal Printer Adafruit has a good one: http://www.adafruit.com/products/597
1 × Small Amplifier & Speaker I used this amp and speaker: http://www.adafruit.com/products/1552 and http://www.adafruit.com/products/1313
1 × 5 volt power supply with 2+ amps of current Adafruit has some good options: http://www.adafruit.com/products/658 or http://www.adafruit.com/products/1466
1 × SPST toggle switch This is used to put the device into 'quiet mode' where no alarms are raised.
2 × Red LEDs I used a couple high power red LEDs to light up the front of the enclosure.
1 × NPN transistor Used to switch the LEDs on and off without pulling too much current from the Pi.