Brett’s new masterclock is Arduino-controlled and keeps very accurate time by periodically synchronizing with the DCF77 “Atomic” Clock in Mainflingen near Frankfurt, Germany. The DCF77 library for Arduino is used to decode the time signal broadcasted from the atomic clock. The time is displayed as hours, minutes, and seconds on six 1″ seven segment LEDs. A 4×20 I2C LCD display is also used in the project to display additional info such as display brightness, sync information, signal quality, auto tune’d frequency, auto tuned quartz accuracy, etc. Both the displays are auto-dimmed based on the surrounding light intensity using an LDR sensor and pulse width modulation technique. His clock also includes a bluetooth link for updating the Arduino firmware from a PC without an USB cable.
Very accurate master clock synchronized to the DCF77 time signal – [Link]
Jürgen Beisert writes:
I like the handy DCF77 signal. In this project no clock should use it, instead the computers in my home network should be served by a precise time reference. Due to the fact most other interfaces are no longer available on modern computers, it uses the USB to forward the prepared DCF77 signal to the host.
DCF77 to USB converter – [Link]
Well, our meetings take place on wednesdays at 10:30 (sharp). A radio controlled clock is used to determine whether you are late (and must bring a cake next time) or not. Unfortunately the identical radio controlled clock in my office always shows a different time
After baking a lot of cakes, I thought about synchronising these disreputable clocks …
Homebrew DCF-77 Signal Generator – [Link]
Using a better antenna to improve DCF77 reception on long distances
We are in the prototyping phase of building a Nixie clock using 1N-14 Nixie tubes. The clock is designed around a PIC16F886 MCU, 74141N BCD decoder/driver and CNY74 optocouplers using common circuit topology. High DC voltage (+ 180VDC ) is generated using MAX1771 step-up switching regulator, which is quite efficient (if you use appropriate components).
Our clock will have some nice features:
- Compact design
- Manual time configuration
- DCF77 time synchronization
- Sync success indicator
- HV shutdown during sync (to reduce noise received by DCF module)
- Super-capacitor time backup
- Thermal protection
- ICSP connector etc.
When clock is complete we will release it as open source-hardware here at Electronics-Lab.com
We decided to use DCF77 signal as time reference for two main reasons, it’s quite easy to receive it and it’s very accurate for the reason that carrier signal is generated from atomic clocks.
But, what about receiving and decoding DCF77 signal? Read the rest of this entry »
This project is a converter from DCF77 to USB, including Windows Software.
USB DCF77 – [Link]
Matthias Franz writes:
The time manipulator is the little brother of the time signal transmitter located in Mainflingen close to Frankfurt in Germany. The very low frequency transmitter located there has an output power of 50 kW and is called, in accordance to its call sign, DCF77 (similar to HBG, MSF, RWM and WWV, WWVB, WWVH). The transmitter is operated by the Media Broadcast GmbH and transmits on 77.5 kHz the official time signal for Germany. The medium range is stated with 2’000 km.
My time manipulator however offers some more functionalities. It’s the true alternative if you have difficulties to find your flux capacitor or your local electricity supplier canceled your contract after you had difficulties to pay off for the 1.21 GW.
Homemade 77.5 kHz DCF77 time signal transmitter – [Link]
The DCF77 Simulator is a combined simulator and demonstrator. It generates DCF77 time code at the same time as it displays the code in different views. The time code to be generated can be set to any time between 2000-01-01 and 2099-12-31.
The simulator can control DCF clocks via two interfaces:
- Radio-signal via a built in low-power transmitter
DCF77 Simulator – [Link]
Receiving the DCF77 signal from Frankfurt. Distance between Frankfurt and Thessaloniki approx. 1500 km
Receiver datasheet : http://www.pvelectronics.co.uk/rftime/SYM-RFT-XX.pdf
More info : http://en.wikipedia.org/wiki/DCF77
Receiving the DCF77 signal in Thessaloniki, Greece – [Link]
The clock is synchronised via the German time signal DCF77. It has a display with automatic brightness control and a RS232 computer interface. Arvin writes:
The clock is built around a PIC16F84 microcontroller from Microchip. I chose this microcontroller since its FLASH memory is easy to program and assembler and programmer software is freely available for GNU/Linux. It has 13 general input/output pins which is just enough to implement all the feature I wanted.
A DCF77 Clock with RS232 Interface – [Link]