Daylight Switch

This project was originally designed for lighting up an illuminated sign for a wine-grower. The sign was originally controlled by a simple time-switch, which had to be reprogrammed every day to avoid the sign's lighting up while it was still daylight. This is time-consuming, and can lead to wastage of electricity and other resources. A better solution would be an automatic switch capable of detecting the transition between daylight and night-time.

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Materials

090049-PCB.pdf

Component list

Resistors
R1 = 47Ohm 1W
R2 = 470kOhm
R3 = LDR
R4, R5 = 100kOhm
R6 =1kOhm
P1 = 1MOhm multiturn preset, vertical
Capacitors
C1 = 1µF5 400V MKT
C2 = 1000µF 25V axial
C3 = 100nF LCC 63V
C4 = 10µF 25V radial
Semiconductors
D1–D4, 6 = 1N4007
D5 = 15V 1.3W zener diode
T1 = BC547 or equivalent
IC1 = µA741 or equivalent
IC2 = 7812, or low-drop equivalent
Miscellaneous
RE1 = relay, 12V coil, 1x 10A, 250V c/o contact
K1,K2,K3 = 2-way PCB terminal block, 5mm (0.2") lead pitch
Type IP55 electricity junction box, internal dimensions 80 x 80 mm (3.15" x 3.15") e.g. plexo LEGRAND # 922-06
20 mm length of electricity conduit, diam. 20 mm (0.8")