Author Topic: Need LED Flasher help  (Read 3472 times)

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Offline NickMak

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Need LED Flasher help
« on: September 29, 2012, 03:24:38 am »
Hello All,

I am new to the blog along with making circuts although it has always interested me I finally have some $$ to play around with.

What I am trying to make is a circut that will flash about 20 of the below LEDs. This is my first project so please go easy on me. Would like to use a 9volt battery (maybe 2 since I heard they don't last long) WHat is a good flasher to use?


Thanks
Nick

LED:
Size: 5mm
      Forward Voltage (V):DC3.2~3.4
      Forward Current (mA):20
      View Angle: About 25 degree
      Luminous Intensity: 5000-7000mcd
      Lens Color:Water Clear
      Emitting Colour:Blue

 
      Resistance Value : 470 ohm&220 ohm
      Power Rating : 0.25W 
      Resistor Tolerance : +/-5%



-
 

Offline TerminalJack505

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Re: Need LED Flasher help
« Reply #1 on: September 29, 2012, 05:01:55 am »
There are a lot of ways to blink LEDs.  The circuit you use depends a lot on how you want each individual LED to behave.  Are all of the LEDs going to blink simultaneously?  Or individually?  Or in groups?

So far as the battery goes, you would get more juice out of 4 AA batteries.
 

Offline NickMak

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Re: Need LED Flasher help
« Reply #2 on: September 29, 2012, 06:08:34 am »
I would want all LED to blink at once ( have all led on at same time off at same time) Prefer a fast blink. After a small bit of research I have found a 555 chip that looks like it would help, is that right?
 

Offline FJV

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Re: Need LED Flasher help
« Reply #3 on: September 29, 2012, 06:50:35 am »
Is trying a simple led flasher and using 1 or 2 transistors to "beef up" the signal enough for lighting 20 leds an option?

http://wild-bohemian.com/electronics/flasher.html



http://www.retrospieler.de/e-flashbutton.html



 

Offline TerminalJack505

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Re: Need LED Flasher help
« Reply #4 on: September 29, 2012, 06:56:02 am »
Yes, the 555 is probably a good IC for this particular application.  It will make generating the on/off signal easy.

The next thing to decide on is the system voltage you'll be using since this will determine how many LEDs can be put in series.

Then you will need to solve how you will drive that many LEDs from the 555 IC.  A 555 timer can source or sink 200mA so you may or may not be able to drive all those LEDs directly from the 555's output.  If it were me, I wouldn't push my luck.  I would use one or more transistors to drive the LEDs.  The 555's output would then just need to drive the transistors' gates and/or bases which would be much less of a load for the IC.

 

Offline NickMak

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Re: Need LED Flasher help
« Reply #5 on: October 02, 2012, 05:29:15 am »
Awsome, Thanks for all the help. I will let you all know how it works out and what I finally decide to try .

Thanks
Nick
 

Offline NickMak

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Re: Need LED Flasher help
« Reply #6 on: October 02, 2012, 05:53:05 am »
Can I use relays where the LEDs would go ?
 

Offline TerminalJack505

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Re: Need LED Flasher help
« Reply #7 on: October 02, 2012, 06:25:15 am »
Yes, you could do that so long as you don't need to switch the relays on and off too fast.  The relays would need to have the appropriate voltage and current ratings and you would want to put a flyback diode across the relay's coil terminals.
 


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