Ton Giesberts
About the article

Light Therapy Box

Blue LEDs combat the Winter Blues

Light Therapy Box
During the winter many people suffer from Seasonal Affective Disorder (SAD), which is commonly known as the winter blues. With the help of blue light these symptoms can be reduced. The blue-light generator described here has a built-in timer and is perfect for this task.
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Gerber file

CAM/CAD data for the PCB referred to in this article is available as a Gerber file. Elektor GREEN and GOLD members can exclusively download these files for free as part of their membership. Gerber files allow a PCB to be produced on an appropriate device available locally, or through an online PCB manufacturing service.

Elektor recommends its business partner Eurocircuits as the company of choice for its own prototypes and volume production in selected cases.

Component list
R1,R6 = 150kOhm
R2 = 2.2MOhm
R3,R8 = 100
R4 = 100kOhm
R5 = 220kOhm
R7 = 10kOhm
R9–R16 = 15kOhm
R17–R58 = 270
P1,P2 = 1MOhm potentiometer, linear
P3 = 100kOhm preset, horizontal
C1,C5,C6,C9 = 100nF MKT, lead pitch 5mm or 7.5mm (0.2” or 0.3”)
C2 = 2.2nF MKT, lead pitch 5mm or 7.5mm (0.2” or 0.3”)
C3 = 82nF MKT, lead pitch 5mm or 7.5mm (0.2” or 0.3”)
C4 = 4.7nF MKT, lead pitch 5mm or 7.5mm (0.2” or 0.3”)
C7,C8 = 1000µF 16V axial, lead pitch 28mm (1.1”)
C10 = 1nF ceramic, lead pitch 5mm (0.2”)
L1 = 40µH 2A, axial (Epcos B82111EC23, Farnell- # 9753354)
D1,D2,D3 = 1N4148
D4.–D87 = blue LED, 5mm, 300mcd, wavelength 465nm, (e.g. Optek OVLLB8C7, Farnell # 1678692)
D88 = Schottky diode 60V 2A, (e.g. STPS2L60, Farnell # 9907637)
T1 = SPP18P06P (P-channel MOSFET 60V 0.13O, Farnell # 1056550)
T2–T9 = BC547B
IC1 = 4093
IC2 = 4060
IC3 = 4015
S1 = push button, panel mount
2-way pinheader, right-angled
2-way pinheader
2 3-way pinheader, right-angled
2 3-way socket
PCB # 081066, see
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