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Flashing LED project - help needed

Discussion in 'LEDs and Optoelectronics' started by JayBlake, May 5, 2013.

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  1. JayBlake

    JayBlake

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    Apr 22, 2013
    Hi everyone.

    Hope someone is able to offer some advice.

    I've attached a hobbled-together diagram of what I'm trying to achieve which is as follows:

    I have 3 x LED's which I can get to flash through the judicial deployment of NE555N Chips, resistors and capacitors.

    I also have a rocker on-off-on switch.

    Diagram [A] shows the switch off and all three lights off.

    Diagram shows the switch to the left on, the centre and left lights on and the right light off.

    Diagram [C] shows the switch to the right on, the centre and the right lights on and the left light off.

    Currently, I am having to employ a 555 Timer (3 in all) and capacitors/resistors for each LED.

    Is there an easier and/or more efficient and/or cheaper and/or less labour intensive method by which I might achieve the same, is anyone able to share?

    Many thanks.

    Jay:)
     

    Attached Files:

    Last edited: May 5, 2013
  2. duke37

    duke37

    5,364
    769
    Jan 9, 2011
    If you just want the leds to flash, then flashing leds are available to run from 3.5 to 14V with no external components. The flasher circuit is inside the led.
     
  3. JayBlake

    JayBlake

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    0
    Apr 22, 2013
    Yeah, I've heard of flashing LED's (considerably more expensive than non-flashers, though, I've also heard).

    Was hoping for another way to get around having to use a 555 chip for each as I've got shed-loads of non-flashing LED's already available.

    Unless anyone knows of a source for cheap flashing LEDs:):)
     
  4. JayBlake

    JayBlake

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    Apr 22, 2013
    A thought has occurred. I don't think I did a very good explanation of my problem which is, on reflection, that even if I wire up the three led's as independant circuits (be it with flashing LEds or 555 chips) given that I only have two on positions and given also that I must therefore wire up the middle LED to each of the switch's ON positions, won't the current simply pass through to the light circuit that I do not want to light, resulting in all of the lights (right, left and centre) coming on, regardless of which of the switch ON positions I have selected (if that makes sense).

    Please see new drawing, attached (and assume red to be live and green to be ground).

    Thanks to anyone and everyone for reading and I do hope someone can help this dinosaur out.:confused::)
     

    Attached Files:

    Last edited: May 5, 2013
  5. duke37

    duke37

    5,364
    769
    Jan 9, 2011
    Maplin do flashing leds at about 75p, there are cheaper ones on e-bay.

    The Maplin leds will work from up to 14V. It may be possible to use a 12V power supply and put 4 or 5 standard leds in series so that when the flaher takes current, the others will flash also. They may not extinquish completely, you may have to do some experimentation
     
  6. JayBlake

    JayBlake

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    Apr 22, 2013
    Thanks Duke.

    Way, way, way too expensive though (I'm looking at eventually using hundreds of the blighters).

    Also, it doesn't solve my cross-circuit-current-flow issue, which I fear remains whether I use flashing LEDs, 555 Timers or even static LEDs - in this particular project.

    Thanks again though, anyway.

    It's appreciated.:)
     
  7. JayBlake

    JayBlake

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    Apr 22, 2013
    Does anyone know if there is a "circuit-breaking" chip or other component that, if I click to the left ON switch position (which initiates the left and centre circuits) will simultaneously cut continuity between the centre circuit and the right circuit (and vice-versa)?

    There surely must be (or there's money to be made by someone clever enough).
     
  8. CocaCola

    CocaCola

    3,635
    5
    Apr 7, 2012
    It's called a diode... You can steer the direction of electricity based on the location(s) you install diodes...
     
  9. JayBlake

    JayBlake

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    Apr 22, 2013
    Thank you, I guessed there must be something out there to perform the function I need.

    This is all a wonderful learning experience for a novice such as myself and I'm very pleased with what I've discovered through a mixture of guidance and experimentation.

    Next research subject =

    DIODES.

    Thanks again for your help.:)
     
  10. duke37

    duke37

    5,364
    769
    Jan 9, 2011
    You could use a three position rotary switch to select any one of the three strings. A fourth position would enable all strings to be energised with some diodes.
     
  11. JayBlake

    JayBlake

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    Apr 22, 2013
    Thanks.

    Is that a potentiometer?
     
  12. duke37

    duke37

    5,364
    769
    Jan 9, 2011
    No a potetiometer is a resistance with a sliding contact. They are used as volume controls on radios for example.

    A three position switch is like a band switch on a radio with distinct switch positions.

    Connecting lots of leds in parallel and then using excess voltage is a recipe for disaster. You should connect multiple leds in strings with a current limiting resistor in each string
     
  13. JayBlake

    JayBlake

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    Apr 22, 2013
    I'll come back to the 3-position-switch but, in the meantime, I've hooked up 160 LEDs in parallel and fed by a mains A/C adaptor pumping 3volts. They are fed through a 555 chip and via 2x470 and 1x1000 resistors. I've had them running and flashing for days with no apparent degradation or overheating of the chip. Am I fooling myself in thinking the circuit is sound, do you think?
     
  14. JayBlake

    JayBlake

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    Apr 22, 2013
    Incidentally, on the subject of potentiometers, I ordered a pack of mixed ones from eBay. After a week or so, I queried why they hadn't arrived and learned they were dispatched from Hong Kong. It was suggested I contact my local Post Office. So I did. Turns out they have been held up at Customs as being suspicious items (although my door's not yet been smashed in at 2am by the anti-terrorist squad - despite their having my address from the label on the envelope). Strange times we live in, indeed.
     
  15. duke37

    duke37

    5,364
    769
    Jan 9, 2011
    Don't get too worried, my niece orderd me some gubbins from the far east. It has been over two weeks and I am still hoping.

    I do not understand how you wired the 160 leds. At 20mA/led, that would need 3.2A, way above what a 555 can do. Where were your resistors?
    Try to draw a circuit diagram with what you have done and please describe just what you need then we can suggest a circuit and the necessary power supply.

    It's now pat my bedtime!
     
  16. CocaCola

    CocaCola

    3,635
    5
    Apr 7, 2012
    I feel the pain for other countries customs, the US is so damn lenient on small packages it's almost a non-issue... Especially for electronic components that are duty free even if they did inspect them and look into what was in the package...

    In all my years of importing stuff (thousands of dollars a year) I have only had one package molested by US customs, and it was an order of 200 unpopulated custom run PC boards... They actually opened each and every individually vacuum packed brick of 25 boards... Then taped the entire mess back together with a bunch of lime green Homeland Security tape, a tape job that would have made a 5 year cringe in horror...

    On the flip side I shipped an item to England and the customer never contacted me again with a problem... Nine months later and long forgotten said package arrives back at my door in the US, apparently UK Customs had a question for the customer and possible duty owed and the customer never got back to them, so it sat in UK Customs for 9 months waiting for him to claim it before they decided to return it to me...
     
  17. JayBlake

    JayBlake

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    Apr 22, 2013
    I think it may be that the package contents description contained the word "Potentiom" (the monkeys probably read it as "Potential" as in "We got ourselves a Potential Ometer here, lads!!!").

    Chances are they are still Googling what an "Ometer" is:D:D:D

    Anyway, I've ordered some diodes and a load of other stuff (from UK suppliers - more expensive but quicker and less likely to raise suspicion than if they were from "Johnny Foreigner" - sad world we currently abide in).

    Am well excited.

    All this started from a request for help from a buddy and now I'm in over my head. Experimenting, inventing and always pushing my (albeit tiny little) envelope of knowledge.

    Thanks for all the help and guidance, guys.:)

    Hopefully my Flux Capacitor will be fixed, once my new Sonic Screwdriver arrives.;)
     
    Last edited: May 6, 2013
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