Master Clock Bluetooth to Samsung S3 by Brett Oliver, on Flickr
Udo Klein has now added "Auto Tune" to his DCF77 library. When the DCF77 reception is good the DCF77 library now tunes the on-board quartz crystal to the DCF77 signal. In the event of the signal being lost the quartz crystal is able to keep the clock running for days without loosing a second.
I have now added this to my clock. The LCD display now also shows the tuned quartz crystal frequency and accuracy.
You can see a video of this working along with many others on my Master Clock Mk2 site here http://home.btconnect.com/brettoliver1/Master_Clock_MK2/Master_Clock_MK2.htm
The clock has the following functions
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
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 within 1 sec over a number of days
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
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
