555 Timer Help

Discussion in 'The Projects Forum' started by Hobbles, Jan 11, 2009.

  1. Hobbles

    Thread Starter New Member

    Jan 11, 2009
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    Hi was wondering if it is possible to have an audio signal go into a 555 timer and come out with a vibration (or like it flicking a switch over and over really fast) sound to it. I experimented and the only thing i can get is the song with a annoying beat that covers the song at 29 hertz. Can the 555 timer just vibrate the audio signal or does it need to have the 9v going through it to? Basically i want to implement it into a guitar effects pedal but if it cant be done o well especially if it dont sound good. If it cant can you post a ic that may work instead (i cant really use micro controllers even though i could get this in a heart beat if i could i dont have enough money for one).
     
  2. Wendy

    Moderator

    Mar 24, 2008
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    Sound and vibration are pretty closely linked, so you'll need to define vibration a bit better. I've bought pager vibrators, they are motors with little weights offset on the shaft designed to operate off 1½V. Are you after a pager/cellphone style vibration?
     
  3. jj_alukkas

    Distinguished Member

    Jan 8, 2009
    753
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    Ohh I guess he's a electric guitar buddy.. Are you trying for some special effects like flanger??
    555 can be used but is not recommended.. If you need to use that better, first make the beat or vibration or whatever you want and then mix it with the audio signal using a audio mixer stage.. Ensure a capacitor is there in between the output of 555 and the mixer to avoid DC ripple to destroy your beats.. I just have the idea, there are great geniuses around here who can help you with the circuitry and other alternatives.
     
  4. Farlander

    Active Member

    Oct 14, 2008
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    I think this can be done easily with a FET.
    You'll need a power source as close to your input audio voltage as possible. Radioshack sells them or you could convert a PC power supply.

    Now, build an oscillating timer circuit using the 555 (like below). You may have to search around to find a good one but there are a ton online. If you get one with 2 pots you can adjust the "switching" duty cycle and frequency.

    You run the output of the 555 (pin#3) to the gate of a FET, and your original audio source goes to the FET source pin. The fet drain is your new "switched" audio output.
    Luck!
     
  5. Hobbles

    Thread Starter New Member

    Jan 11, 2009
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    Sorry if i sound confusing its hard to explain. I use an electric guitar that obviously goes to the amp. Well a better example is like turning down the volume really quick then turning back up over and over except with the 555 timer it would be sharper (kind of like a switch but a switch makes noise as it gets flicked which is kind of where im at with the 555 timer). I dont no if any body hooked up a 555 timer to an amp but it makes its own beat also shown when it turns on an led it adds the 9v, to power the 555 ic, to the signal making it unpleasent. So i just want the audio to stop and play over an over without the added volts from the 555 timer. Looking at it the 555 timer is probably not a good ic to use for it. Im gonna try a something interesting i heard from farlander if the input voltage is close enough the same it may work i will give it a try thanks everyone.

    * update nope for some reason i cant even get the darn thing to run at 4.5 volts. I got se555's lying around so thats what im using ti's se555 page.
     
    Last edited: Jan 11, 2009
  6. Farlander

    Active Member

    Oct 14, 2008
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    I think the 555's operable range is 5-30V, no?

    Put a voltmeter on the output of your guitar amp. If you get anywhere between 5-30V, then a 555 might work for you easily, otherwise you will need a more expensive type of FET called a Trench FET, which can carry a different voltage than the signal that switches it. I suspect though you will probably need a line level FET and something other than a 555.

    It's like this -- you build the 555 timer circuit. The pulse output of the 555 turns ON the FET and carries your audio signal, only during on pulses, so yes it's like cranking the volume up and down only much cleaner/faster.
     
  7. Wendy

    Moderator

    Mar 24, 2008
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    Actually a 555 top is 18VDC. It's in the datasheet.
     
  8. rbkxiiowe

    Member

    Mar 13, 2009
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    I think what hobbles means is to use the 555 timer to switch on and off the guitars output to the amp really fast giving a stuttering effect to the sound.

    There's a similar idea here: http://little-scale.blogspot.com/2007/08/blog-post.html

    This one uses a 4093 as an oscillator to switch the guitar's input through a 4066.

    Can the same be achieved by using a 555 as the oscillator?
     
  9. bertus

    Administrator

    Apr 5, 2008
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  10. rbkxiiowe

    Member

    Mar 13, 2009
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    I just tried using a 555 timer set up as an astable oscillator instead of the 4093 trick mentioned above. It has much the same effect but there's also a horrible throbbing from the amp in time with the oscillations. Can anyone tell me why this is happening and how to get rid of it?!
     
  11. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
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    The "throbbing" you describe could be caused by a DC bias being switched on and off into the signal, this is very hard on amps/speakers, as it drives the cone to full excursion, into clipping. Somewhat like connecting just a battery to the input jack.

    Do you have a schematic of your circuit?
     
  12. rbkxiiowe

    Member

    Mar 13, 2009
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    Yes -

    [​IMG]
     
  13. rbkxiiowe

    Member

    Mar 13, 2009
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    Any ideas? DC voltage shouldn't be getting to the output should it?
     
  14. rbkxiiowe

    Member

    Mar 13, 2009
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    Just in case anyone's still listening -

    I realised the unwanted sound is more of a click than a throb, and I found that by putting a 1uF cap from the output of the 4066 to ground it filtered the high frequencies and eliminated the click. Unfortunately it's now not much good as a guitar effect as the guitar has lost its high frequencies as well.

    I still don't understand where the clicking is coming from....
    I'm not much good on this stuff yet but I am trying to learn!
     
  15. TheBellows

    Active Member

    Jan 18, 2009
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    I guess you want a kind of tremolo effect?

    Maybe you can try making a LFO with a 555 and use a LED output,
    then you can put an LDR in front of the LED in a lightproof container to make a resistor that changes resistance like the pulses of your LFO.

    I usally just cover the components with some heat shrink tubing to make it lightproof.
    You can also use a lightproof Hammond box.

    You may let the signal go through the leads of the LDR and you will have a tremolo effect without any circuit messing up your signal.

    The sound will be somewhat reduced, but with some additional circuitry you may have a quite good sounding tremolo effect.
    Maybe a preamp circuit will do the trick?
    I haven't used the LED/LDR module to make a guitar tremolo effect yet, but i use it in some amateurish synthesizer circuits.
     
  16. SgtWookie

    Expert

    Jul 17, 2007
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    Did you realize that this thread had no posts after 20 March of 2009?

    A 555 would not be a good candidate for the project, as it momentarily places a dead short across Vcc/GND when the output changes states. A 4093 doesn't exhibit this extreme behavior. They probably weren't using bypass caps across the Vdd/GND pins of the ICs, which would result in lots of noise.
     
  17. TheBellows

    Active Member

    Jan 18, 2009
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    I realized that after i posted. :p

    I dont think you understand what i meant...the ic is in a separate circuit with a separate power supply, the LDR is not connected to the oscillator it's just changing resistance because the LED is flashing.


    signal in-LDR-signal out

    I don't see how this can produce noise unless the LDR is a noisy component itself...
     
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