I got annoyed by our doorbell (very loud and heartstopping schrill sound) and I startet building one using a arduino controller but then I realised that it would be much more fun to be able to change/ install doorbell sounds via network on the doorbell, no SD card removing and plugging into the cardreader and plugging back in, just ssh or ftp into your doorbell and upload a new soundfile! When the new Raspberry Pi model A+ came out it was setteled and I needed a nice enclosure for the electronics and the two loudspeakers. Printing the case isn't easy but its doable, I included my gcode file created with Simplify3D for my Makergear M2 printer. I printed this with PLA and used a raft. The Raspberry Pi Model A+ is mounted on two slides (see included file) which fit into the enclosure. The doorbell button is connected to GPIO7 and is beeing read via event_detect (interrupt) in python. The loudspeakers are driven by a Stereo 3.7W Class D Audio Amplifier - MAX98306 which I bought here: http://www.exp-tech.de/Shields/Audio/Stereo-3-7W-Class-D-Audio-Amplifier-MAX98306.html The loudspeakers are 3" 4 Ohms 3Watt and have to be glued into the case: http://www.exp-tech.de/Zubehoer/Sonstige-101/Lautsprecher-3-Durchmesser-4-Ohm-3-Watt.html Usually in Germany there is a little 8V/1A AC transformer in the electrical cabinet for the standard doorbell. I replaced it with a 5V/ 2.4A DC switching supply for DIN-Rail from Reichelt electronics: https://secure.reichelt.de/Schaltnetzteile-fuer-Hut-Schiene/MW-DR-15-5/3//index.html?ACTION=3&GROUPID=6539&ARTICLE=148095&SEARCH=MW%20DR-15-5&OFFSET=500&WKID=0&