Home › Magazines › 2009 › July/August › Automatic Bicycle Light

Automatic Bicycle Light

Published in issue 391, July/August 2009

Automatic Bicycle Light
The circuit takes the ambient light level into account and only turns on the light when it becomes dark. The light is turned off when no cycling has taken place for over a minute or if it becomes light again. The biggest advantage of this circuit is that it has no manual controls. This way you can never 'forget' to turn the light on or off. This makes it ideal for children and those of a forgetful disposition.

Components

Resistors
R1 = 1MO (SMD 0805)
R2,R4 = 100kO (SMD 0805)
R3,R6 = 1kO (SMD 0805)
R5 = LDR e.g. FW150 Conrad Electronics # 183547
Capacitors
C1 = 1µF 16V (SMD 0805)
C2 = 10µF 16V (SMD chip type)
C3 = 100nF (SMD 0805)
Semiconductors
T1 = BC807 (SMD SOT23)
T2 = STS6NF20V (SMD SO8)
Miscellaneous
S1 = reed switch (not on board) + 2-way right angle pinheader
BT1 = 3–12V (see text)

Click below to download a PDF copy of this article from Elektor magazine.

 

Downloads 

Article PDF
5 Elektor Credits
PCB PDF
Free download
 

Order this magazine 

Magazine July/August 2009
UK391 (US $ 11.30)
 

Order from ThePCBShop 

PCB, bare

Please note. In view of the complexity of international markets, Elektor cannot guarantee the availability of components for this project.

Subscribe now

Subscribe to our free
E-weekly Newsletter!

Enter your Email address:

Front Panel Express


Design your unique front panel with our free CAD software - it is quick and easy! Front Panel Express will machine your design with modern CNC technology. You will receive the panel exactly as you need it in a couple of days.
Instant download

FAQ

Before submitting questions, review our FAQ section!

Spotlight

Elektor 1990 through 1999

This DVD-ROM contains the full range of 1990-1999 volumes (110 issues, more than 2,100 articles) of Elektor Electronics magazine.