About the article

Rugby MSF Controlled Alarm Clock

A digital alarm clock which decodes and synchronises itself to the time signal picked up from the Rugby ‘MSF’ transmitter on 60 kHz.This is a project I have had in mind ever since I did my final year project at University. At that time, the 8080 and other microprocessors such as the 6502 were around, and would have been capable of doing the job. However, the necessary design tools were not available at reasonable cost for the home user, and neither was the modern PC. So the project went on hold for a good few years.
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Component list
Receiver board (Figure 3)
S1 = 3-way mini DIN socket
Galleon 60 kHz receiver module, Maplin # MK68Y
MSF antenna, Maplin # MK72P
Receiver PCB (available from author)
Processor board (Figure 4)
R1 = 47? fusible resistor
R2,R7 = 10k?
R3 = 240?
R4 = 27?
R5 = 680?
R6 = 47k?
R8 = 39k?
R9 = 120?
RN1,RN2 = 100k?
C1 = 100µF 50V radial
C2,C8 = 1µF 63V radial
C3,C4 = 33pF ceramic
C5,C6,C10,C11 = 100nF
Tr1 = 2N3904
Tr2 = 2N3906
U1 = LM317 (TO220, vertical mounting)
U2 = AT89S53-24PC (programmed)
U3 = 74HCT245
U4 = X25320P (Xicor)
U5,U6 = CD4016
U7 = LM324N
RB1 = bridge rectifier DF005M (IR) (20V, 1A)
S1,S2 = connector, Berg 76342-308
P3 = 10-way IDC header
J1 = 3-way SIL pinheader with jumper, 0.1 in. pitch
P2 = connector, Molex 22-27-2021
P1 = connector, Molex 22-27-2031
SW1 = pushbutton, Omron B3F-3100
SW2,SW3,SW4 = pushbutton, Omron B3F-3150
PS1 = piezo sounder
X1 = 12MHz quartz crystal
Lock/eject socket for microcontroller, Aries 40-C182-10 (Farnell # 177821)
Enclosure, type BM22W, Farnell #531870
Display filter, Farnell # 177145
Mains adaptor to suit (see text)
Processor PCB (available from author)
Display board (Figure 5)
R1 = 10k?
R2 = 3k?6
R3,R7,R10,R13,R16,R19,R22,R23 = 1k?5
R4,R8,R11,R14,R17,R20,R24,R25 = 1k?8
R5 = ORP12
R6,R9,R12,R15,R18,R21,R26,R27 = 150?
C1 = 10µF 25V
C2,C3,C4,C5,C6,C7,C8,C9 = 4nF7
TR1,TR3,TR5,TR7,TR9,TR11,TR14,TR16 = 2N3906
TR2,TR4,TR6,TR8,TR10,TR12,TR13,TR15 = 2N3904
U1 = ULN2803A
P1,P2 = connector, Harwin M20-9970806
Display PCB (available from author)
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