Circuit to continually alternate two flashing lights?

phaxmohdem

Golden Member
Aug 18, 2004
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www.avxmedia.com
Greetings. I'm bored and decided to throw together a LAN Party PC out of spare parts. I got a hold of an old ATX case and cleaned it out, and put the old Spray can to it, and noticed it kinda looks like a cop car now in its new White/Black clad paint job. I am going to make a red/blue light bar for the top of it and need some help with the circuitry:

What I want:
Two lights (LED's in this case) they stay lit for around one second, before turning off and the other one turns on at the same time, simple alternating, continous cycle.

What kind of circuit components do I need to make this happen? I have very limited knowledge of electonic components, I just need help selecting parts to make this work. Parts need to be available at radio shack preferrably.

Any Ideas are certainly welcomed.

EDIT:

OK So I've reconsidered the whole light bar thing... after some reflection it would look decidedly ghey, but I'm still interested to learn what components could make this happen.
 

PottedMeat

Lifer
Apr 17, 2002
12,363
475
126
Dual LED Blinker Kit with Explanation

You can get all the parts at RadioShack, for some reason there is no schematic in the PDF I linked but the book 'Getting Started in Electronics' has it in the back ( also available at Ratshack the last time I looked ).

You should have to experiment with the values of C1 and C2 to get the desired flashing rate.

If for some reason they dont have a 2N3904 NPN Transistor, just substitute it with some other cheap NPN.
 

Peter

Elite Member
Oct 15, 1999
9,640
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No, just not the kind of question that should be asked here. I mean, probably every digital electronics DIY tutorial STARTS with something like this.
 

TuxDave

Lifer
Oct 8, 2002
10,571
3
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You can build one with two transistors, some resistors and a cap. Google 'astable multivibrator'. For the resistors and caps you can pick them up anywhere along with two discrete transistors. Just hook up the LED to the two outputs and watch them flash.