LED blinking circuit
- Thread starter zmoz
- Start date
Sigman
* The Arctic Moderator *
Are you looking for a pre-fab "do it yourself" 2 Flashing LED Kit or Adjustable Flashing Rate 2 LED Kit or merely a schematic to build one from scratch?
Or you can merely buy pre-made 3 volt snap on battery pack red LED flasher for $1. Of course there's shipping & handling. I ordered 25 of the simple 3 volt red LED flashers and put them on Christmas gifts...it seems like they flash FOREVER!
Or you can merely buy pre-made 3 volt snap on battery pack red LED flasher for $1. Of course there's shipping & handling. I ordered 25 of the simple 3 volt red LED flashers and put them on Christmas gifts...it seems like they flash FOREVER!
JSWrightOC
Enlightened
You can also build a simple LED flasher that will run off as little as 1.5V using an LM3909 and a couple of other components. All parts are available from Radio Shack. This circuit uses very little power, so it will flash for a LONG time. Schematics involving the 3909 should be readily available; check RS's Mini Engineer's Notebook series.
Or...you could go with the flashing LED. It depends on what kind of "flash" you want. The 3909 circuit produces a strobe-like burst of light, whereas most flashing LEDs have a 50/50 or 30/60 (on/off) duty cycle.
Or...you could go with the flashing LED. It depends on what kind of "flash" you want. The 3909 circuit produces a strobe-like burst of light, whereas most flashing LEDs have a 50/50 or 30/60 (on/off) duty cycle.
JSWrightOC
Enlightened
Well, I don't know how useful this information is going to be to you...National discontinued this part back in 1998, and no one else makes it. /ubbthreads/images/graemlins/frown.gif /ubbthreads/images/graemlins/mecry.gif
Too bad, this was a really cool chip. You could even use it as an oscillator that would directly drive a speaker. A single C cell would power this thing for over a year flashing an LED...
You can take a look at National Semiconductor's datasheet on the LM3909.
I also found this which depicts the 3909 wired up to a 1.5V cell and a single capacitor. Larger caps will yield slower (but brighter) flashes.
I do not think Radio Smack carries this part anymore. I can't find it through any common distributors (Digi-key, Jameco, etc.)...so it looks like this may not be an option...sorry!
Too bad, this was a really cool chip. You could even use it as an oscillator that would directly drive a speaker. A single C cell would power this thing for over a year flashing an LED...
You can take a look at National Semiconductor's datasheet on the LM3909.
I also found this which depicts the 3909 wired up to a 1.5V cell and a single capacitor. Larger caps will yield slower (but brighter) flashes.
I do not think Radio Smack carries this part anymore. I can't find it through any common distributors (Digi-key, Jameco, etc.)...so it looks like this may not be an option...sorry!
Check out this web site - parts are at radio shack:
555 Timer IC page
If you can read a schematic - this will do it for you. Good luck!
555 Timer IC page
If you can read a schematic - this will do it for you. Good luck!
JSWrightOC
Enlightened
The 555 will work, but it's quite a bit of overkill and horribly inefficient for flashing an LED. There's also a hefty minimum voltage requirement.
Perhaps a simple transistor oscillator circuit would work?
Manufacturers of semiconductors have datasheets on their products, for instance, http://www.national.com. These datasheets include descriptions, pinouts, and sample applications useful for design.
Perhaps a simple transistor oscillator circuit would work?
Manufacturers of semiconductors have datasheets on their products, for instance, http://www.national.com. These datasheets include descriptions, pinouts, and sample applications useful for design.
radellaf
Flashlight Enthusiast
I'm interested.
As for his circuit, I thought the idea to use an LED with a built-in flasher was by far the simplest. To blink many, you can use that LED in series with others, or you can have it drive a transistor.
As for his circuit, I thought the idea to use an LED with a built-in flasher was by far the simplest. To blink many, you can use that LED in series with others, or you can have it drive a transistor.
Self flashing LEDs
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tonyb said:
the built in flashers run off of 12volts only no chioce of led either.
[/ QUOTE ]
While it's not RS, All carries 'all colors' of 3 to 5 VDC self flashers at two for a buck, more or less or less: <http://www.allelectronics.com/matrix/Flashing_LEDS.html>.
Hard to beat for simple....
Doug Owen
[ QUOTE ]
tonyb said:
the built in flashers run off of 12volts only no chioce of led either.
[/ QUOTE ]
While it's not RS, All carries 'all colors' of 3 to 5 VDC self flashers at two for a buck, more or less or less: <http://www.allelectronics.com/matrix/Flashing_LEDS.html>.
Hard to beat for simple....
Doug Owen
[ QUOTE ]
JSWrightOC said:
The 555 will work, but it's quite a bit of overkill and horribly inefficient for flashing an LED. There's also a hefty minimum voltage requirement.
Perhaps a simple transistor oscillator circuit would work?
[/ QUOTE ]
Ahhh, but the poster was looking for simple and readily available. I also suggest that the CMOS version of the chip would probably much more efficient than any discreet transister circuit. The CMOS version works down to 1.5V.
You can fool with the nearly indestructable LM555 and then upgrade to the pin compatible CMOS 555 when you get some experience.
JSWrightOC said:
The 555 will work, but it's quite a bit of overkill and horribly inefficient for flashing an LED. There's also a hefty minimum voltage requirement.
Perhaps a simple transistor oscillator circuit would work?
[/ QUOTE ]
Ahhh, but the poster was looking for simple and readily available. I also suggest that the CMOS version of the chip would probably much more efficient than any discreet transister circuit. The CMOS version works down to 1.5V.
You can fool with the nearly indestructable LM555 and then upgrade to the pin compatible CMOS 555 when you get some experience.
LED-FX
Enlightened
Simplest is the self flashing LED, generally two flavours 12V which will flash happily on a 9V PP3 battery and 5V which will operate down to about 3 Volts.
With a PP3 battery clip and some hot melt glue you can make a neat flashing marker light.
Can also wire a couple of `normal` hyper bright LEDs in series with the flashing LED to get hyper bright flashing LEDs, no resistor required.
Or wire a couple of flashers in parallel with a non flasher in series with them and get an interesting flicker light.
Think a database of circuit ideas is a great idea.
Adam
With a PP3 battery clip and some hot melt glue you can make a neat flashing marker light.
Can also wire a couple of `normal` hyper bright LEDs in series with the flashing LED to get hyper bright flashing LEDs, no resistor required.
Or wire a couple of flashers in parallel with a non flasher in series with them and get an interesting flicker light.
Think a database of circuit ideas is a great idea.
Adam
