Flash Speed

Discussion in 'The Projects Forum' started by mapleman555, Apr 4, 2015.

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  1. mapleman555

    Thread Starter Member

    Dec 15, 2014
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    I'm looking for slow LED flash speeds. I bought a 10,000uf capacitor today and that gives me a flash speed of about 2-3 seconds. I want to slow it down even more. Are there higher value caps or is there another way to slow it down. I have a friend who has a miniature train set with a harbor at the back edge of his setup and he wants a "lighthouse" effect out in the water. Maybe even a slow on/off look to it. Any suggestions?
     
    Last edited: Apr 4, 2015
  2. bertus

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    Apr 5, 2008
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    Hello,

    Take a 4017 and drive the led with one of its outputs.
    It will slow-down by a factor of 10.

    Bertus
     
  3. Papabravo

    Expert

    Feb 24, 2006
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    A microcontroller will give you a much wider range of flash speeds than you could ever get with analog components. One of those little 8-pin jobs should be perfect.
     
  4. mapleman555

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    Dec 15, 2014
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    Thanks, I'm now looking up microcontrollers for flashing and fading. Goody, I may have to order some more electronics stuff.
     
  5. blocco a spirale

    AAC Fanatic!

    Jun 18, 2008
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    Do you have a PIC programmer? I have some code I wrote around 10 years ago for an 8-pin PIC 12C509 that fades an LED on and off using PWM.
     
  6. atferrari

    AAC Fanatic!

    Jan 6, 2004
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    Do you actually intend to flash a LED with a low repetition rate, say one flash every 5 or 6 or 7 seconds, or it is fading (brightness going slowly up and down in a continuous way) what you are after?. If the first, how long the flash takes?

    Is PWM involved in your idea?

    Edit: I see that you want both. ?? /Edit
     
  7. djsfantasi

    AAC Fanatic!

    Apr 11, 2010
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    He wants a model to simulate the light in this video of a lighthouse at night. Note that it starts out dim, builds to a bright light, and then dims out
     
  8. mapleman555

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    Dec 15, 2014
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    If I can't get both speed and fade I'll go for speed.
     
  9. mapleman555

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    Dec 15, 2014
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    Like OMG. Of all the light houses you could pick, Portland Headlight. That brings back a lot of memories. It was one of my favorite places to go the nine years I lived in Maine, I photographed it a lot, that an Pemaquid Point Lighthouse.
    Anyway, that's the right idea. But instead of it turning have it fade in and out.
     
  10. djsfantasi

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    Apr 11, 2010
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    Google "simple fading LED lighthouse circuit". This one that comes up was developed for an HO. Scale lighthouse.
     
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  11. mapleman555

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    Dec 15, 2014
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    I was looking at the 4017 recently, I guess I'll have to order some.
     
  12. Bernard

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    Aug 7, 2008
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    Your 10000 uF should give about 2.75 hours with something like a 555. If you only wanted a 2/10 sec flash every 4 sec, a 555 can do. I think Dave Johnson's ckt. would be neat. For wider viewing angle, wonder what 3 LED's spaced 120 deg. would look like?
    Gone till Tuesday.
     
    Last edited: Apr 7, 2015
  13. bertus

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  14. mapleman555

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    Dec 15, 2014
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    Yes, both the "Knight Rider" and the "Dark Storm" ideas are good.
     
  15. mapleman555

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    Dec 15, 2014
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    Along this line, does any have a link to a flashing row of lights that look like runway lights? A row that goes in just one direction instead of two like the Knight Rider lights.
    Sort of like this but with the white edge lights flashing one by one the length of it .
     
    Last edited: Apr 5, 2015
  16. bertus

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    Hello,

    You can make the following modification to the knight rider circuit to have the leds go only one way.
    When you connect the reset to out7 (pin 6 of U3) in stead of out4 (pin 10 of u5), the leds will only go one way.
    (u4 and u5 can be taken out of the circuit then).

    Bertus
     
  17. mapleman555

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    Dec 15, 2014
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    Thanks bertus.
    From a video I just watched he called his chasing lights. I've seen some stuff about that and started looking it up. I have a roll of strip lights with the 44 button remote, I can experiment with some thing like that but I want to build my own "chase" set-up.
     
  18. bertus

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    Apr 5, 2008
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    Hello,

    In the night rider schematic there are some values given for the fade timings.
    If you use no capacitors on the bases of the transistors the leds will be on and off right away.

    Bertus
     
  19. mapleman555

    Thread Starter Member

    Dec 15, 2014
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    Thanks again Bertus, I will have to give it a closer look.

    Of all the places to find some thing related to this. I stopped at the Dollar Tree store today and what is the first thing I see when I walk in, one of these, http://www.dollartree.com/toys/Nove.../629c1094c1094p341974/index.pro?method=search. It was blinking so I went over to look at it. I push the button to shut it off and it changed the flashing pattern. When you push the button it goes from quick flicker to a sort-of faster chase then to a slower kind of chase. So I bought two of the clear ones and I think I will take one apart.
     
  20. bertus

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    Apr 5, 2008
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    Hello,

    Those sticks will likely have some type of microcontroller in them.
    It might even be in the shape of a cob (chip on board), wich looks like a black blob on the circuit board.

    Bertus
     
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