Voice Door Bell

This device plays a sound file when door bell button is pressed. Originally it was planned to be a part of Smart Home Project, but eventually became separate project, not connected to Smart Home.

The Bell has IR remote control, storage for up to 4 melodies and relatively high output power about 5W, so you can hear it even through a closed door. To upload sound files from PC to the device, RS-232 is used.

I designed the schematics for the device on my own, without samples from the Internet:



There are PIC16F877 MCU, 4 AT24C512 flash ROMs (each can store one melody), AD7302 8-bit DAC, RS-232 (for PC) and RS-485 (for Smart Home) interfaces, TSOP17 38 KHz IR receiver. Since electric door bell button is wired to 220V AC, there is also capacitative voltage divider and optocoupler. An off-the-shelf external module is used as audio amplifier (not shown in schematics).

The PCB for the device turned out too complex to make at home, and I ordered its manufacturing.



The exterior of the Bell is just a white plastic box, so I didn't put a photo of it here.

Here you can download firmware for the device, written in C. Just to see how programs for PIC microcontrollers in C look like and for my programming skills evaluation :)