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"bada bing" "bada boom"

Discussion in 'Electronic Projects Design/Ideas/Reviews' started by timothyjackson, Oct 6, 2004.

  1. timothyjackson

    timothyjackson New Member

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    Hey audioguru,

    Thanks for your time again.

    I tried making the second circuit of Bill Bowden.

    I couldn't make the first becuase when ordering the LM1458, I ordered one with a "m" prefix. Unfortunatley I couldn't "pummel" the Suface mount chip into the prototype board. I threw it out the window instead.

    On the second circuit, I loaded all the components in. I am confused with:

    1.) The connection between Pin 1 of LM324 and pin 5 of the other. There are 2 mid way connections to other midway wire connections. I don't know "how" to wire this up on the prototype board.

    2.) Again, pin 3 on LM324, don't know "how" to connect this up to the wire/channel/link from pin 6 of the other LM324.

    It's all the mid connections which are throwing me off track.

    3.) The LED voltage drop has prompted me to check the spec's on the LED's:

    From the LED technical data, I'm unsure what specifes the voltage drop:

    Vf typ. 1.85 (is this it?)

    MCD is 3500

    RED

    Vr Max. 5

    kingbright part no. L53SRCE

    4.) The capacitor arrangement. I have connected the first one:

    + to slots away from pin 2
    - to a spare slot (unconnected to any other component)

    The second capactor:

    - connected next to the - of the first
    + next to/connected to pin 1

    I'm unsure if the capacitors are doing there job

    5.) I will buy a voltmeter :)

    I like the deep end.

    Take Care

    Timbo
     
  2. timothyjackson

    timothyjackson New Member

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    audioguru...

    I'm away for a couple of days.

    I've booked to se a local electronics chap. Unsure of how much he actually knows.

    Might hit you back tuesday"ish".

    Just thought I'd let you know out of english courtesy.

    Take care.

    Timbo
     
  3. audioguru

    audioguru Well-Known Member Most Helpful Member

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    Hi Tim,
    Oh, so you are building Bill Bowden's circuit with the LM324.
    When you talk about wiring the LM324, you also talk about "the other". Aren't you using just a single LM324? It has 4 opamps inside but only 2 are used.
    The proto bd. has a break in its wiring down the center for the LM324 to straddle so that pin 1 doesn't connect to pin 14, etc.
    Most holes to the left of pin 1 connect to pin 1, and most holes to the right of pin 14 connect to pin 14, etc.

    Connect the parts as in the schematic by plugging them into the appropriate holes. Join pin 3 to pin 6 with a piece of wire.

    Connect the - wire of both capacitors in midair or to the holes that are above pin 1. The capacitors must be close to pins 1 and 2.

    Connect pin 1 with a piece of wire that connects to the bases of both transistors that are plugged-in somewhere else.

    Vf is the forward voltage drop of the LED. 1.85V is fine.

    MCD of 3500 is very bright. Kingbright make them bright by focussing them in a narrow angle. You won't see them very well away from that narrow beam. I always select wide-angle high brightness LEDs.
     
  4. dave

    Dave New Member

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  5. timothyjackson

    timothyjackson New Member

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    Hello audioguru,

    Thanks for your reply. It works.

    You were right. I used two op amps instead of one. I had not activated the power to the first op amp (only the second). Just to test it, I've powered up the first op amp, and correctly connected the cbe of the transistors.

    I have 3 questions:

    1 - I am adjusting the fade rate by up rating the resistor between pin 2 and 7. This is also reducing the LED brightness. Is there a way to increase the brightness of the LED? Would this be through changing the resistance at pins 3 and 6?

    2 - I wish to add more LED's, instead of 2 in each pair, I would like 5, or more. I'm assuming I could connect them up in the appropriate manner (i.e. parellel?)

    3 - Is your fader circuit up yet (hehe).

    Many thanks for your time. I really appreciate it.

    Timbo

    :D
     
  6. audioguru

    audioguru Well-Known Member Most Helpful Member

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    Hi Timbo,
    Good, you fixed it!
    1a) The resistor between pins 2 and 7 should only affect fade speed, not LED brightness. It shouldn't be less than 2K (opamp can't drive less) nor be more than about 1M (cap leakage current). Change the caps for a different range of fading speed (bigger caps make it slower).

    1b) The two resistors at pins 3 and 6 adjust the brightness balance between the 2 sets of LEDs. You can demo an unbalance by connecting a 100K resistor across one of the two 47K resistors.

    1c) The 100 ohm resistors can be reduced (47 ohms, 22 ohms) to increase the brighness until the current is too high and the LEDs burn-out.

    2) It is not recommended to parallel LEDs because they are all not the same. One will have a slightly lower voltage drop and "hog" the current. It will be very bright and maybe will burn-out.

    3) I haven't found the file yet for my Fantastic Fading LEDs project. I have other projects on-the-go, I just finished ordering 100 bright, wide-angle LEDs.
    Just add another 100 ohms resistor with 2 LEDs connected to the emitter.
     
  7. timothyjackson

    timothyjackson New Member

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    Hi audioguru,

    fantastic. Thanks for your knowledge. Really appreciate it.

    I have experimented with a Pot (pleased to say that only one LED burnt out completley). I understand the adjusting of fade rate and brightness through adjusting the resistor values.

    However. I have noticed that, by increasing the brightness, it seems to reduce the fading effect. Do I solve this by increasing the capacitor values?? I have already ordered some and hopefully this will cure the problem.

    Point 2.) from before. Is series connection recommended??

    YOur wide angle white bright LEDs sound interesting. Where you get them from?? What project is it for..

    All the best

    Timbo
     
  8. audioguru

    audioguru Well-Known Member Most Helpful Member

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    Hi Timbo,
    You've burnt an LED already! You have very bright ones, it must have been dazzling just before it said Goodbye.

    When you raise the circuit's bias point, the current ramps are very linear so the fading doesn't change much. The response of your vision is logarithmic so that it has its tremendous range of brightness, and that is why I made my circuit's ramps exponential. Its LEDs fade from very dim to maximum. At very slow fading rates the AGC affect of your vision's iris makes the brightest part appear less.
    You can adjust your pot so the LEDs are very dim at minimum (but only one side), and adjust the 100 ohms for the maximum brightness. Reduce the supply voltage so that both sides are the same. Because the ramp is linear, the brightest part will appear not to fade much, and most fading will occur at near the dimmest.

    Two LEDs in series operate with the same current. Two Leds in parallel (each one with its own current-limiting resistor) require twice the current and the extra power is wasted in their resistors.

    For awhile I've been using Fairchild's (they bought an LED manufacturer) bright, red, diffused and wide-angle (40 degrees, yours are probably 12) MV8191. I get them from Newarkinone and Digikey. If you are British or are from down-under you can try Farnell or maybe it is called Farnellinone.

    I have never purchased a yellowy-blue "white" LED. Shine a "white" LED on something that is red and you won't see much. I make pure white with Red + Green + Blue. My very bright 30 degrees green and blue LEDs are (were, obsolete now) made by Agilent (they bought HP's LED division). They were used in huge commercial pixel screens.
     
  9. timothyjackson

    timothyjackson New Member

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    hey audioguru.

    Think I've reached a plateaux now; I need to start experimenting, and having a bit of fun. Got a few POT's to play with the different values to see what happens with the fading affects. Think this will give me more general confidence a knowledge; "combinative play" I think is what they call it.

    I found some lumen Led's; incredibley high outputs, and comparativley low power consumption.

    For now my curiosity is turning towards what your upto....... unless its top secret... tell me what your creating..

    all the best...

    timbo

    :D
     
  10. audioguru

    audioguru Well-Known Member Most Helpful Member

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    Hi Timbo,
    Have fun with your pots!
    I got some 74HC4017 ICs (they work with a supply voltage as low as 2.0V). I am going to make a bunch of LED chaser thingys with the LEDs in a circle and a variable chase rate and brightness. Only two AA, C or D cells will make then go for quite awhile. Useless toys.
    I promised another electronics chat forum that I would design a sine-wave high power inverter using a Class-D audio amp IC and some Mosfets. I was planning on using National Semi's, but they are going to discontinue it. I'm still looking for a replacement.
     
  11. timothyjackson

    timothyjackson New Member

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    hey audioguru

    Yu know what I love. I love the ease of learning from experts. For example. Last night, I was puzzled by the fading performance of one set of leds, over another in the paired set-up. Eventually, I realised that one set of led's had a different voltage drop to the other set. I'm using several pots to adjust the rates of everything to get the desired effect.

    - What does a 74HC4017 do?
    (hehe... useless toys.. i like that)

    - Class D audio amp??

    - Other sources of IC's, try, www.rswww.com, "avnet", and "Allied electronics".

    - The LM324 produces a "v" wave form. Where can I find a resource to understand IC's that produce waveforms, and, other IC waveforms avaliable. I would love to find a "softer" wave form IC, almost like a "U" instead of a "V".

    - I probably will ask you questions forever, so, you might want to "fade" (hehe) me out slowly so I do resent you for ever...

    Take care..

    Timbo :D
     
  12. jrz126

    jrz126 Active Member

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    I'm not audioguru, but I want to throw in my $0.02 :)
    Glad to see that you are enjoying the wonderful world of electronics. If I'm not mistaken the 4017 is a deacde counting IC. For each clock pulse put into the IC, the counter will count up, which will light another led connected to it.

    It uses square waveforms that have different widths to create the sine wave for the audio output. It's kinda complicated, but it's a pretty neat concept. I think it also allows for smaller components too, I've got a class D amp in my car, it's 700Wrms @ 1 ohm (which is how I'm running it). My old amp was ~200Wrms at 2 ohm. and the amps are just about the same size.

    It all depends on the external circuitry of the op amp. you might be able to get the "u" effect if you add some sort of filter in there. I'm just learning about filters in one of my EE classes. You should try to read up on the basics behind the op amps, they are used in a wide variety of was so it's some good knowledge.
     
  13. timothyjackson

    timothyjackson New Member

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    hey there jrz126

    Thanks for your reply.

    You're expensive!! :D :D

    I have been reading about op-amps, at a real basic level. Already, I think they are obsolutley fantastic. Really, amazing. I love them. One thing which i find so odd, is why my girlfirend doesn't find them as amazing as i do. hey ho.

    The trouble I have is:

    - no electronic training

    However, my desire to learn and produce electronic stuff is full on. At the mo, i'm satisfied with a nice circuit to play about with, tweak, perfect, and finalise. So, in about 3 days, I should be bored of it, and on to the next thing... keep you posted.

    Timbo.

    :D
     
  14. jrz126

    jrz126 Active Member

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    Actually I'm cheap, (I gave you my 2 cents, you didnt have to pay me :wink: )

    I know what you mean about female's interest in electrical stuff. I tried to explain to my now ex girlfriend about how my old roof led circiut worked, and how neat it was. She just had this look like "what are you talking about, why are you wasting your time on this" (we broke up for different reasons though)


    don't let the "no electrical training" get you down though. I'd suggest to just keep looking into how to apply electronics to your other interests. Be careful though, you might become too interested in electronics and want to get a degree in electrical engineering, like I did, and college is not too kind to engineers. :(
     
  15. audioguru

    audioguru Well-Known Member Most Helpful Member

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    Hi Timbo,
    You guys watch out for mistakes in your learning, I have seen errors in textbooks, datasheets (a Japanese LM317 with a "protection" diode backwards!) and directly from my prof! I taught my prof a thing or two.

    The 74HC4017 lights 10 LEDs, one at a time, and I mount them in a circle so that they "chase" around and around. Useless! I have already made a few for my friends and now they need a dimmer for them.

    My "Fantastic" circuit avoids differences in LED voltage drops and other voltage problems by using a current feed instead of a voltage feed for the LEDs.

    If you want a smooth dimming effect, you need my "Fantastic" exponential circuit. It starts very dim then increases brightness faster and faster until it reaches max. The the opposite occurs, it slowly dims then gets faster and faster, etc.
    Another way to make smooth fading is with a sine-wave. It increases its velocity in the middle, like a pendulum.

    I might make an LED KnightRider circuit, using a sine-wave for a pendulum effect. It will look smoother than this linear one:
     

    Attached Files:

  16. timothyjackson

    timothyjackson New Member

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    true true. Im the same with curtains though. can't stand them. prefer shutters.

    audioguru......you're very teasing with your fantastic led circuit...its always on the end of a string... just dangling there. I like the night rider sequencial led set-up. .....can you show a basic circuit diagram for it???

    timbo
     
  17. audioguru

    audioguru Well-Known Member Most Helpful Member

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    Hi Timbo,
    Here's a couple of LED toys that use the same parts but operate very differently. They use a 9V battery, which I think is a waste, to light 2V LEDs. Have you ever seen the 6 tiny cells inside a 9V battery? Very small.
    Most of my LED circuits use a 3V battery, which is much more efficient and cheaper.

    These circuits will work with two LEDs in series, and then maybe you can eliminate (a piece of wire instead) their current-limiting resistor):
    6-LED jerky, linear, KnightRider project:
    http://www.electronics-lab.com/projects/motor_light/035/index.html

    Dancing LEDs, with microphone, project:
    http://www.electronics-lab.com/projects/motor_light/021/index.html
     
  18. timothyjackson

    timothyjackson New Member

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    morning audioguru

    i like those. Both of them.

    Never seen any 3V batterys. Can you recommend a website which sells them....post the http:/ rather than explaining them...

    I like the noise circuit. I was imagining...a panel of leds...which are totally random in illumination...you could specify a really sensitive mic to get that effect. Why is there a seperate section to the right of the circuit.

    In the knight rider circuit,,,, between the led's and the ic, is are they diodes?? what value are they..

    keep it coming..

    have a great day..

    timbo
     
  19. audioguru

    audioguru Well-Known Member Most Helpful Member

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    Hi Timbo,
    You haven't seen a 3V battery? Two AA cells. They have at least 6 times the capacity of a 9V battery. Cost less too. These circuits won't work with only 2 to 3V but mine do.

    The Dancing LEDs project uses an electret microphone. You can't spec a more sensitive one because they are all about the same. Just use a volume control for R4 or R5 (gain adjustment). The separate section is for driving up to 5 LEDs in series instead of just one like in the schematic, for a total of 50 LEDs (but you need 10 of those transistor circuits).

    The diodes in the KnightRider project can be any small one like 1N914 or 1N4148. The diodes "gate" the LEDs so that the outputs of the 4017 light them in the reverse order, so the 7th count lights the 5th LED, the 8th count lights the 4th LED, etc.
     
  20. chemelec

    chemelec Well-Known Member

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  21. audioguru

    audioguru Well-Known Member Most Helpful Member

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    Thanks Chemelec,
    Ha, Ha. That's a good one.
    It would work a whole lot better if its LEDs weren't upside down!

    Try it with a 2-pole low-pass-filter following the 555's capacitor for a nice smooth fading effect, and an offset adjustment to match the LED's forward voltage to the diodes voltages.
     

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