LED's to create a light effect for ocean diorama.

Discussion in 'The Projects Forum' started by cpqfe29, Jan 22, 2012.

  1. cpqfe29

    Thread Starter New Member

    Jan 30, 2010
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    Thank you in advance for any help that you can provide.

    You have helped me twice before on my Daughters school projects (I did not post but the information was here and helped me.) So far we did a simple solar panel and led to illustrate renewable energy on a poster and then later we used a 555, decade counters (4017 + 4022) and potentiometer to create the earth's orbit on another poster using LED's in variable sequence. VERY cool. It has made both of my Daughters interested in electronics and we already made a couple of those Velleman kits.

    I have searched but I can't seem to come to a clear answer on how I should tackle our next project. We built an ocean reef diorama in a large shoe box. We would like to use six soft white or blue [or both] LED's staggered on top of the box to create the illusion of how sunlight 'dances' through shallow water.

    I believe that six LED should do the trick and that two LEDs should be on at all times then either fade out or just swap out to the next pair with a total of three pairs. Did that make sense? 6 LEDs. 2 on at a time. 3 pairs.

    I would greatly appreciate any input. I would like to keep it small [if possible] and I don't care about # of components. I do not even have to put this on strip board as I can spread the components on the back of the shoebox (I will if I need to of course). My main concern is HOW do I pull this off?

    Notes: LEDs are coming from 75% off Christmas lights (3mm or 5mm) – various colors, no specs. I have a lot of 3 volt CR2032 ‘button’ batteries and holders. I do not need to run the LEDs at full power (I know I can adjust that via resistors value once I have a setup). Must be done by this Friday so simple is likely better in this case. I will breadboard it to test. That should cover it.

    Again Thank You in advance for any and all suggestions that you all may come up with. It is very much appreciated.
     
    Last edited: Jan 22, 2012
  2. Wendy

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    Mar 24, 2008
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    Your old friend the 4017 will likely come in handy.

    It is possible someone will help you come up with a µC circuit (microcontroller).

    The fade in/fade out is where it will be challanging.

    Done anything with a protoboard yet?
     
  3. Wendy

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    Mar 24, 2008
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    OK, I think I have a way, but you will have to do some trial and error.

    LEDs, 555s, Flashers, and Light Chasers

    Chapter 12 - Special Effects

    Throbbing LEDs

    [​IMG]
    .................................................. ..............Figure 12.1

    Try building one, if you like it then I can show you how to sequence it like you want.

    Q1,2 is either a 2N2902A or a 2N2222A, respectively.
     
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  4. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    Hey I did something like the fading LED thingy ..
    it's some where in this forum....U guys need to dig it up.
    Cause I got to dive into my recovery drive to find the PIC ASM.
     
  5. cpqfe29

    Thread Starter New Member

    Jan 30, 2010
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    If I put a potentiometer on pins 2,6, and 7 could that control the amount of 'throb' or will it mess up the circuit? I think I have everything. If not then RS sells the the 2N2222A in a 15 pack of NPNs. I will breadboard this and get back with you here. THANK you!



     
  6. Wendy

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    Mar 24, 2008
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    Note: pin 5 is not connected to anything. If you use pin 5 that will mess up the circuit. The pot controls how fast it flashes, when you get a speed you like you can measure the pot and replace R1 and R2 with one resistor. I like things simple myself.

    If you use a blue or a white LED bump the power supply up to 12VDC. 9V will work, but I think 12V would work better.
     
    Last edited: Jan 23, 2012
  7. Bernard

    AAC Fanatic!

    Aug 7, 2008
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    A suggestion: Use two of Bill's throbbing 555's, second ckt with NPNs, 2N2222, first slow, two blue in parallel; second medium speed, one white paralled with a blue; a third 555 to add sparkle, Bill's Articles, 555 Projects, 555 PWM, with two whites in series, a ltttle faster with about 30% duty. In the throbber ckt , cap ouly swings 1/3 of supply is reason to parall LEDs.
     
    Last edited: Jan 23, 2012
  8. Wendy

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    Mar 24, 2008
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    I was thinking of adding a 4017 sequencer later. It is possible the OP will want more than one LED to help light things up.

    The sequencer circuit should be fairly straight forward, at least that is my thought.
     
  9. cpqfe29

    Thread Starter New Member

    Jan 30, 2010
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    Thanks for the help.

    I built the circuit and it is an awesome effect.

    ** Just for others that may search this: I had to get some more transistors. Radio Shack # 276-2617 had 15 in the pack. 5 each of 2N2222, 2N3904, and 2N4401. I look at the spec sheets and they are somewhat similar. I did try each type and all three work well. I also purchased RS 276-1604 with 15 PNP transistors (2N3906) and will see if they work with the first circuit from Bill – just to see **

    I also was able to connect more LEDs in parallel. I had up to eight and nothing was unusually warm but I don’t want to drain the supply too fast so three to four will be nice.

    I do like the 4017 idea and would like to see the circuit please. Not just for me but if someone searches for something similar or specifically for your suggestion above.

    Bernard,
    Your suggestion is great also. I can imagine what you are saying but I may make it bit simpler due to time ( L ).

    Maybe using a 556 to throb two sets of three or four parallel linked LEDs. I would like the “throb” rate to be the same (for now) but to throb opposite of each other. Is that possible? If so then this may be the simplest way to create a basic water movement effect (third grade project and yes my daughter will solder it herself with my supervision and help of course.)


    Side question --- sorry. Is there any software that will lay out a circuit on breadboard/ strip board /boards with individual pads for each hole? I know there is software to do custom made boards but for simple projects like this it would be nice to find a way minimize the footprint and to save it for future use (555 templates for example).
     
    Last edited: Jan 24, 2012
  10. KJ6EAD

    Senior Member

    Apr 30, 2011
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  11. Bernard

    AAC Fanatic!

    Aug 7, 2008
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    To throb inversley, using 2N2222 ckt, add a 555 conected as invertor- input from first 555, pin 3 to only 2 & 6 of second 555, connect output, pin 3 to RC ckt, say 22μF & 100k pot. Neg side of C to gnd, + side to R & darlington pair to drive LED in parallel or in series. Adjusting pot will control depth of throb, almost gnd & + rail.
     
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  12. Wendy

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    Mar 24, 2008
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    Throbbing of this type inverted is the same, there is no difference. This is because the waveform is symetrical on all axis.

    I'll come up with the 4017 circuit ASAP.
     
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  13. Bernard

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    The difference looks like 180 deg to me; where did i Go wrong?
     
  14. cpqfe29

    Thread Starter New Member

    Jan 30, 2010
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    I had the NPN version built on a bread board. I wanted to try out those PNP transistors from RS also (BTW they were three different kinds even though the packaging only mentioned one type - RS 276-1604 - 2N4403, 2N2907, and 2N3906. They all worked with the first schematic from Bill.

    I stumbled upon something neat. Since I bread boarded this already using the NPN version I just built the PNP part on another breadboard. I jumpered the second board to the first and I forgot to take off the signal wire the NPN part.

    To my surprise both parts throbbed opposite of each other! I was able to test it with up to four LED's (two soft white and two blue) on each side. Although I only need about six.

    I built it on protoboard. Used a pot to control throb speed, and changed the resistor value to make the LEDs dimmer. So far it has been running for a couple of hours (not installed on project) without any problems. Nothing is warm and seems to work well.

    Does anyone see a problem with this setup?

    Again... I used Bill's circuit. I used BOTH the PNP and the NPN sides using the same (only one) 555 timer. I am currently running 8 3mm LEDs in parallel (four per side) off of a nine volt battery. The LED's seem to be low power and are from Christmas light strings.

    Thanks.
     
  15. Bernard

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    Congratulations, you achieved what I was suggesting, but saved one 555 in the process. I can see that you & your daughter are going to have lots of fun with this project.
     
  16. Wendy

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    Mar 24, 2008
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    Good enough. I wasn't thinking of one circuit for both of the LEDs. If you built two 555 circuits, one with the PNP and one with the NPN transistors you couldn't tell the difference.

    Welcome to the world of designing your own circuits. That is basically how it is done.

    Still want the 4017 circuit?
     
  17. cpqfe29

    Thread Starter New Member

    Jan 30, 2010
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    We made you two a video thank you here: http://youtu.be/C31lUWhNfNo .
    You can see the project (almost complete) and the fruit of your generosity at the link above.

    Yes Bill, I would still like to see the 4017 circuit at your convenience please. I am about to place an order to stock up on these wonderful ICs as I can see that I will be using them quite a bit. We had so much fun building this one that both of my daughters want to make another circuit. Them wanting to learn is better than playing the WII all day. J
     
  18. Wendy

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    Mar 24, 2008
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    Good enough! Tell your girl she is very welcome.

    About the circuit, pin 4 on a 555 is a reset pin. If you were to disconnect that pin and use with with a 4017 you could sequence the 555 as you wanted.

    OK, a 4022 is very similar to a 4017, with 8 outputs instead of 10. I came up with this several decades ago, it has worked well every since.

    [​IMG]
    ........,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,............Firgure 9.1

    Of course, the 4017 can do the same thing. There is even commercial kit out there with a printed circuit board available from Electronic Goldmine (they have a lot of good kits). Its schematic probably looks a lot like this...

    [​IMG]

    One by one each LED will light, reach the end of the chain, and start over. Instead of connecting the outputs to an LED you could connect it to the 555 pin 4. Actually you could leave the LED circuit intact and still connect it to the 555 pin 4, it would still work. You could add some diodes to lengthen out the on times, allowing the various 555 circuits to be more out of phase, which should create even better effects.
     
    Last edited: Jan 29, 2012
  19. Georacer

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    Nov 25, 2009
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    I believe that is the first video "Thank you" response here in AAC. It was so cute! Thank you cpqfe29.
     
  20. Bernard

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    In post 18, 4017 ckt, seperate cathode resistors can be used with different colored LEDs, & to give different brightnesses. Also could try adding a cap in parallel with some LEDs, to round off the edges. A driver would be needed if more LED are connected to single outputs; 20mA is pushing outputs, but will work if there are no other loads on outputs.
     
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