Xronos Clock keeps time with the ATmega644p

The Xronos Clock Kit (v2.1) – which recently hit the virtual store shelves at Adafruit – is an open source, hackable and customizable device powered by Atmel’s ATmega644p microcontroller (MCU).

Aside from Atmel’s ATmega644p MCU, key hardware specs include:


256MB microSD card
  • 22Khz 16-bit Mono uncompressed WAV (audio support)
  • 32×16 Red/Green LED matrix (capable of producing 3 colors: red green and orange)
  • 3x 24mm arcade buttons
  • DS1307 based RTC w/ LIR2032 battery
Digital DS18B20 temperature sensor (-55°C to +125°C)
  • RFM12B (915 Mhz or 434 Mhz) only available in V2 as option
  • USB programming w/ optional FTDI adapter/cable (not included)
  • 6-12 VDC (positive tip) Power Supply
  • 1-3 Watt draw (aprox., depends on Color and Brightness)
  • 7.5″ x 4.75″ x 3.75″ (aprox), 1 lb 8 1/4 oz (687g) w/o external Power supply

The talking clock is equipped with an internal backup battery, while all settings are saved to flash memory (EEPROM). Meaning, alarm setting and preferences will be preserved during a power outage. 

Since all audio files are kept on SD card inside, users can change alarm tones, or replace voice prompts with their own.

Additional features include:

  • Dual custom alarms
  • 10 alarm tones, such as melodies or special effects like trains, thunder or police sirens
  • Change display color to green, red or orange
  • 12 or 24 hour mode
  • Celsius or Fahrenheit selection for temperature sensor
  • Ambient light sensor automatically adjusts display brightness
  • Easy access to micro SD card, backup batter and FTDI

The Atmel-powered Xronos Clock Kit (v2.1) is currently available on the official Adafruit store for $215.

2 thoughts on “Xronos Clock keeps time with the ATmega644p

  1. Pingback: Plotting time with an Arduino Uno | Bits & Pieces from the Embedded Design World

  2. Pingback: What time is it? These DIY clocks say it’s Maker time! | Bits & Pieces from the Embedded Design World

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