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.

You even can play internet radio, or make announcements with it.

Updated the python script, added a sql-lite db for logging rings added a command to pause my mpd music player via network in case somebody rings and I hear music and overhear the "bell".

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 (see small included script). I soldered a 20nF ceramic cap between GPIO7 and GND to block interferences coming in over the cabel and also a 4.7k pullup resistor to 3.3V.

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/lautsprecher-3-durchmesser-4-ohm-3-watt?___SID=U

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&

The python script uses sox (play) to play the sound files, so you have to install a few things first:

sudo apt-get install sox lame libsox-fmt-mp3

after that you should be able to play sounds:

play some-soundfile.mp3

use alsamixer to change the volume.

The script expects the soundfiles in the folder "/home/pi/door-bell/sounds" and plays them randomly.