Slogan: easy and awesome

Door Bell

I though that would be very nice to have a cool sound at the door bell. With an Atmega32 I made a WAV/PCM file player. The files are read from a SD card. It is very easy to read data from a SD card because the card controller has SPI interface and also the Atmega has the same interface. Then I used the call signal from the door bell to start playing a file. At the next press of the bell button a counter is incremented and the next file is playing.

On internet are a lot of AVR projects that interface the sd/mmc card with AVR-microcontrollers, even some wav/pcm plyers. I found the software of these projects to complicated and I wrote it myself as simple as possible. So I implemented the fat16 (only read), SPI sd card driver and a pcm file player. I put the source code under BSD-License and can be found in the download section.

I can split the electronics in three parts (see the schematic):

  • preparing the input signal
  • the sd card player
  • the amplifier with TDA7056B (5W)

The schematic can be found in Eagle format in the download section. You can see now the functional sd-card player on the breadboard:

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