How can I make a LED blink on and off?

I just ordered some 3mm leds, and I would like to know more about them. One thing is how to make it blink on and off. If someone could help me that would be great.

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AndyGadget8 years ago
The absolutely simplest way is to buy a blinking LED. These have the flashing circuitry built in.
schoonovermr (author)  AndyGadget8 years ago
where can i buy those?
Any electronics store, either high-street or on-line (Maplin, Mouser etc) or they're dirt-cheap on eBay.
That link I gave you was rubbish - mainly quantities of 1000 and from far east. Try THIS.
alexrocks7 years ago
us an lm3909, you can find them on futurlec.com for cheap
seandogue7 years ago
simple enough to use a 555 timer set to astable mode (it runs as a clock) to drive the LED.

See http://www.national.com/ds/LM/LM555.pdf page 7 under "Astable Operation" for a circuit that requires
1 555 timer, 2 resistors, and two capacitors, plus, of course, the LED and its current limit resistor) (it would be the lower "Rload" between pin 3 and ground in figure 4 of the cited document)...

very easy.
But I do agree with the "blinking LED comment below mine
rickharris8 years ago
Depending on how complex you want to go:

1. Buy a flashing LEd they are cheap.
2. Go down the microprocessor route and have many more options. try http://www.picaxe.com lots of information there - Forum is good too.
Kiteman8 years ago
You could just sit flicking a switch on and off, or you could try these search results.