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 for cheap
seandogue8 years ago
simple enough to use a 555 timer set to astable mode (it runs as a clock) to drive the LED.

See 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 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.