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Arduino DCF77 Master Clock with pulse outputs for driving electromechanical slave clocks

A Master Clock synchronised to the DCF77 radio clock that provides pulses for slave clocks

  1. oliverb
    Arduino powered DCF77 Master Clock for driving electromechanical slave clocks
    See 4K demo video below showing clock chiming 10 0'clock

    Arduino 328 Microprocessor is used to decode Time & date from the DCF77 "Atomic" Clock in Mainflingen near Frankfurt Germany

    The DCF77 signal is decoded using the fantastic new DCF77 library written by Udo Klein meaning the clock stays in sync even with a massive amount of noise on the received DCF77 signal http://blog.blinkenlight.net/experiments/dcf77/dcf77-library/

    Udo Klein's DCF77 library continually "Auto Tunes" the quartz crystal so in the rare event the signal can't be decoded the clock remains accurate to within 1 sec over many days see his blog here for full details http://blog.blinkenlight.net/

    The clock provides the following pulses to drive slave clocks 1 sec alternating, 30 sec, 1 min , 1 hour, 24 hr, 15 min chime of quarter hours, hourly chime of hours

    Primary display of time in hours, minutes & seconds are displayed on 1" (26mm) green LED 7 segment displays using a MAX7219 IC.

    Secondary 4x20 I2C LCD display is used to display time & date, fast or slow seconds, summer winter correction, display brightness, sync information, signal quality, auto tune'd frequency, auto tuned quartz accuracy and summer winter time mode

    The primary and secondary displays are auto dimmed using and LDR and Pulse Width Modulation

    The primary and secondary displays are shutdown during daytime and are activated by Passive Infrared detection when someone enters the room

    Manually triggered automatic Summer/Winter time correction of 30 second slave clocks

    Blue-Tooth link for programming, clock pulse status and PIR adjusting

    Auto leap second adjustment of 30 second slave and 1 second slave clocks time and date of leap second can be read via Blue-tooth on your PC or Android mobile or tablet

    Recording of fast or slow 1 second slave clock pulses on the LCD display as well as time and date stamping of last fast or slow pulse accessible by Blue-Tooth on your PC or Android mobile or tablet

    Below-Details of Blue-tooth output to PC or Android


    Circuit details below

    Full construction details including many pics and Arduino code can be found on my master Clock page