Strangeness of this clock is in its expression of numbers, which is realized using seven Leds. Leds are located inside a pipe, one above another and if we move Leds enough fast left or right, we have a space where we can write numbers, characters or anything else. source
Clock circuits
Propeller Clock
This is Propeller Clock.A motor spins the “propeller”, and a small microprocessor keeps track of time and changes the pattern on seven LEDs with exact timing to simulate a 7 by 30 array of LEDs. It is an illusion, but it works nicely.source
Propeller Clock : A Mechanically scanned digital clock
The PIC16F84 that is used is a very basic& cheap FLASH µController from MICROCHIP.
It has 13 digital I/O’s of which just 5 are used here. The PIC16F84 has no analog inputs or outputs.The controller is ideal for experimenting because it can be erased and re-programmed 1000 times.For easy time calculation the circuit used a 10.24 MHz Xtal. source
DCF77 Clock based on Basic Stamp
This application interfaces a DCF77 receiver module to a BASIC Stamp® microcontroller. The DCF77 module receives time information from the standard time transmitter in Mainflingen, Germany. The BASIC Stamp module converts this information to RS-232. Each second it output’s a complete time string at 2400 bps.
DCF77 is a longwave time signal and standard-frequency radio station. Its primary and backup transmitter are located in Mainflingen, about 25 km south-east of Frankfurt, Germany. It is operated by T-Systems Media Broadcast, a subsidiary of Deutsche Telekom AG, on behalf of the Physikalisch-Technische Bundesanstalt, Germany’s national physics laboratory. DCF77 has been in service as a standard-frequency station since 1959; date and time information was added in 1973.
Digital DCF77 clock with LCD and gong
With this digital DCF77 clock with LCD and gong,you always get the right time and date.This project make use of a PIC16F628(A) and a DCF77 receiver.The DCF77 is a longwave time signal and standard-frequency radio station. Its primary and backup transmitter are located in Mainflingen, about 25 km south-east of Frankfurt, Germany. It is operated by T-Systems Media Broadcast, a subsidiary of Deutsche Telekom AG, on behalf of the Physikalisch-Technische Bundesanstalt, Germany’s national physics laboratory. DCF77 has been in service as a standard-frequency station since 1959; date and time information was added in 1973.source