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Switching with 4066B

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  • Switching with 4066B

    Note: Here I only show the complete connection of accordion button C.
    Each gate (ins 5, 6, 12, 13) has a 22K pulldown resistor to ground.
    The are 2 groups ( group Minor IC1 to IC3) and group 7th IC4 to IC6)

    Pressing accordion button C sends +5V to SW pin 4 of IC1 and when I press Minor foot switch +5V are send to all gates of IC1 to IC3
    Result: I get a chorus of all switches on from IC1 to IC3, but I only wanted to have C and a# activated via the accordion button C and Minor foot switch.
    What am I doing wrong?

    The good thing on this circuit is that only +5V is switched.
    There must be a way of doing it with diodes and resistors, instead 4066B? Using the resistors to earth out the signal from either group, because the same accordion C button serves both (Minor & 7th) groups, but shall only serve one group at a time! How to do it?

    The problem with 4066B >>> Since I need to control each group via a foot switch; i.e. one foot switch for the Minor group (IC1 to IC3) and one foot switch for the 7th group (IC4 to IC6).
    That's why I thought to connect e.g. the 12 gates of the Minor group together to a foot switch to activate the desired gate. Yet, that also allows the other 11 gates to float (away from ground), causing them to wrongly activate their gates...
    Last edited by jjj; 04-01-2007, 03:23 PM. Reason: adding text

  • #2
    Using diodes & resistors instead 4066B???


    • #3
      Can I recommend you don't start two threads on the same project? Now to get any information from the other thread I have to close this one, go find it and then reopen this one.

      Your drawing is unclear. The way it is drawn tells me that closing the C-acc switch sends 5v to all three outputs: A, B, C. Press the 7th switch and then +5 goes only to B and C. Press minor switch and +5 goes to only A and C. Is that what you want?

      WHat accordion is this? Can you post the circuit you want to control? I have the impression you might be controlling accompaniment?

      Is there one master 7th and one master minor for the whole scale, or is there a set of two switches for each note of the scale? That is are we looking at something working into the control circuits or are we looking for something to wire into that sea of left hand buttons?

      We need to see the rest of the circuit, because you mentioned pull-downs. Your horizontal resistors will form voltage dividers with the pull downs, so they need to be low enough in value so the result at points A and B are at a valid logic HIGH. THEN we worry about the angled resistor We would calculate what it needed to be to bring the line back to a logic LOW. But as you meentioned, we want it to be large enough valyes so as not to load the +5.
      Education is what you're left with after you have forgotten what you have learned.


      • #4
        Can I recommend you don't start two threads on the same project? Sorry about that... and thx for your labor of love to kick me to re-think my 'layman circuit'.

        Your drawing is unclear Very true, what I need is this: Normally both, Minor & 7th outputs should be earthed out, so that pressing accordion C-Button sends +5V only to C output. If then I want MINOR, I open SW Minor and a# tune is added (visa-versa with 7th)
        So, this circuit is repeated for the whole octave (12 times):

        WHat accordion is this? ...accompaniment?
        ĄCorrecto! This circuitry I only used to switch Live-Styler (YamahaStyles) accompaniment software, because I want to connect 120 accordion pentagonic buttons (from an old Fafisa electronic accordion) to my Synth.
        Normally, the software works in the lowest octave of a Synth; requiring to additionally momentarily press the next black key to its left to obtain MINOR or the next white key to its left to obtain 7th accompaniment.

        ...we want it to be large enough values so as not to load the +5 PS. Yes, that was my worry... It won't be too bad, because the outputs go to 6x 4066B (QuadSW) and then to the key SW of Synth (my Roland D20 has 2 switches per key!) For chords, another 6x 4066B! So, there are only microA at work, making it easy to earth out Minor & 7th currents.
        If I'm helplessly lost, I'll have to just build a test module two 5K Pot's and then reduce its resistance until it works safely...
        On a second thought... maybe I could connect my 120 accordion buttons via diodes directly to the Synth switches? In that case I only need about +3V for the lot. Not too sure if the Synth switches will work that way? They work with 4066B on +5V at VSS.
        Last edited by jjj; 04-03-2007, 05:01 PM.