Rhine Tower clock Mk II

The DCF-controlled LED clock design, published in the May 1998 issue of Elektor Electronics, is a radio-controlled electronic version of the clock mounted on the Rhine Tower in Düsseldorf. Inspired by the many positive reactions to this project, its designer has reworked the software to add new features. To make things even nicer, Elektor Electronics has designed a special circuit board in the shape of the actual tower in Düsseldorf.Building a circuit yourself is even more pleasant when the result is something unique. Those of you that have built the original DCF-controlled LED clock will certainly have experienced this first-hand. Anyone who sees such a clock for the first time will undoubtedly wonder what it is and how it works.The clock that is integrated into Düsseldorf’s Rhine Tower consists of a series of lights arranged in a vertical line. The 39 lamps that are used to indicate the time on the tower are replaced in this project by yellow LEDs.

Resistors:
R1,R2 = 47kΩ
R3=220Ω
R4,R5,R7 = see text
R6 =10kΩ
R8 = 1kΩ8
R9 = 1kΩ
R10 = 4kΩ7
Capacitors:
C1 = 4µF7 63V radial
C2 = 4-22 pF trimmer
C3,C4 = 47pF
C5,C6,C7 = 100nF
C8 = 1000µF 25V
C9 = 10µF 25V radial
Semiconductors:
D1,D46,D47,D48 = LED, high eff., green
D2-D40,D56 = LED, high eff., yellow
D41-D45,D50-D55 = LED, high eff., red
D49 = 1N4001
T1 = BC557B
IC1 = AT89C2051-12PC (order code 996519-1)
IC2 = ICM7218A IJI
IC3 = 7805
Miscellaneous:
JP1 = 2-way jumper
K1,K2 = 20-way boxheader
Two 20-way sockets and a piece of flatcable
S1,S2,S3 = pushbutton ,type
‘Digitast’ with integral LED (ITT Schadow)
X1 = 12 MHz quartz crystal
Bz1 = dc buzzer, 5 or 6 V
Heatsink for IC3 (15 K/W, e.g., ICK35)
PCB, order code 990076-1
Optional: DCF-module (Conrad Electronics order code 64 11 38-55)