• Display: Six cold cathode neon readout (nixie) tubes Z573M, (or ‘digitrons’, as we call them here)
  • Time: Radio DCF77 module receives precise German time, backed up by a 32.768kHz watch crystal.
  • Remote control: infra-red (IR) sensor, software decoder for Sony remote controller I’ve got
  • Processor: AVR ATmega32 (8-bit, 32kB FLASH, 2kB RAM)
  • Storage of voice samples on SD card (e.g. 1GB) with FAT16/32 filesystem
  • Sound converter: 12-bit DAC with SPI interface (using MCP4921)
  • Amplifier: 1.5W (using TDA7233)
  • Debug: UART/RS232, AVR ISP interface

All the resources–software source code, schematic, and PCB layouts–are on github: https://github.com/jsyk/Talking_Clock

Some more detailed description on my web page:  http://www.jsykora.info/?page_id=240