A Maker by the name of Brett recently completed building his DCF77 Master Bracket Clock. As the HackADay crew notes, DCF77 is a longwave time signal whose transmitter is located near Frankfurt, Germany. Each minute, the precise date and time are broadcast via the 77.5kHz carrier signal.
“The result, which you can see above, is made using an Ikea lantern, a skeleton clock, an Atmel ATmega328 MCU (for Arduino compatibility), a voice recording playback IC (ISD1730), a cheap 20×4 LCD display, a DCF77 receiver module and many LEDs,” explained HackADay’s Mathieu Stephan. “In case the clock loses power from the power supply, three AA cells provide battery backup.”
More specifically, time is displayed on a skeleton clock and a blue 4×20 LCD display. Clock pulses to drive slave dials are monitored on an LED panel, while the main board is equipped with a USB to UART connector so the clock’s software can be updated from a PC. In terms of software, including Atmel’s versatile ATmega328 MCU in the build allowed Brett to use Arduino libraries which helped facilitate rapid coding for the DCF77 Master Bracket Clock.
Interested in learning more? You can check out the project’s official page here.