Please see circuit below... in (my) next posting!

 

Have a look at a diode-resistor AND gate: http://people.deas.harvard.edu/~jones/es154/lectures/lecture_7/dl_rtl_demo/diodgate.html%23c2

 

Thx for kicking me to re-think my circuit. I copied the AND & OR Gate circuits. 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):


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.
I want the resistance to be large enough values so as not to load the +5 PS. 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.

 

I miss Mozikluv... He could've handle this in his sleep.

 

You might be able to answer ...a 'tiny' question:
If I connect 24 resistors to earth tonto the same foot switch I would have to add a diode (anode to foot switch ground) to each of them to seperate them? Otherwise I get a chorus, instead the selected tune combination?

 

All I can say for certain is that TTL inputs interpret open as high. If A#, B, and C are TTL inputs, then your "C Accordian" button won't turn off.

Have you considered a series of AND gates?

 

The 120- button accordion accompaniment requires:
12 notes for major chords (3 in 1), 12 notes for minor chords (3 in1), 12 notes fro 7th chords (4 in 1) and 12 notes for diminished chords (3 in 1), as well as 12 notes for major bass and terz bass.
My idea: I thought of connecting e.g. C accordion chord buttons via diodes to C, E, G blocks (i.e. in total 12 such blocks for 12 tunes of an octave), which than via an 'electronic switch' activate the Synth key switches.
I'm not sure how AND gates could do the job?
Perhaps you can show how it's done (just for C-chord)?

 

I don't know a C-chord from a chord of wood, but I'll try to whip up a diagram of AND gates with i/p and o/p labled similarly to yours. I've a long weekend in front of me, so please be patient.

 

Then I better give you some more info on my project:
I want to do 2 different jobs: 1) First I want to connect my 120 bass accordion box onto my Roland Synth. 2) I want to add a circuit to control Live-Styler (Yamaha Styles) software via my 120 button accordion box. The accordion box is the part of a piano accordion where the buttons are. The 120 button box is from an old, electronic Farfisa accordion... (The rest of the accordion isn't there anymore, for I only use the 120 button box!) The 120 buttons are:
20 buttons for terz bass, one tune ea.
20 buttons for major bass, one tune ea.
20 buttons for major chords, 3 tunes ea.
20 buttons for minor chords, 3 tunes ea.
20 button for 7th chords, 4 tunes ea.
20buttons for Dim chords, 3 tunes ea.
http://www.accordionpage.com/basar.html Each button (of the 120 buttons) has only one contact. Of course, to make chords, I need to to wire 3 to 4 tunes onto it e.g. accordion chord button C via a diode to C,E,G blocks (12 such blocks). From there I than wire them to the 4066B gates (i.e. 3 x 4066B for chords and 3 x 4066B for bass & terz). I already prepared the chord charts and numbered every diode connects (13 diodes each in each block; cathode down; 12 blocks of it for chords only) so, I find faults faster, later on. To wire it up is a hell of work, but I'm used to madness.

My Roland (D20) Synth has 2 key switches on each of its 61 keys. I have got the service manual. Here are 3 Roland key switches for keys C, E and G:

Activating all three gives the C-major chord! I did my test: Closing only one SW of the two Synth key switches won't work. The only other way is to create one switch (from the two Synth switches) is, by connecting e.g. at C-chord G via diode and H via diode together and this held onto 8 creates 'one' switch and it worked! This cuts the amount of 4066 (quadSW) in half. Now I need only 3 x 4066. At first I was worried that this might interfer with the Synth keyboard's velocity, but no it doesn't.
Beside, I invented a kind of wrapping method/ tool (a siringe tube with sanded endings connected to an empty yarn coil), which feeds 0.09mm polyurethane (Philips) copperwire. (I got 2kg of that stuff!) With that I just 'wrap up' all connections and directly solder them, burning off isolation. 100's of channeled wires take amazingly little space! I can show you a photo of some 40 IC's (4066) connected this way... if you insist.
I think by using 4066B (quadSw) I already solved project #1... I don't think there's a better way? Unless you know how to though a miracle.
This is the circuit of the second project:

The output (A#,B,C) of this circuit connects to 4066 switches of the accordion box. This circuit connects two 'odd' notes together, because I only use it, to control Live-Styler (Yamaha-Styles) accompaniment software, which requires momentarily to press the next black key to the left (on the Synth keybd) to switch to MINOR or a white key to the left to switch to 7th accompaniment mode. I still need some help on that (values of resistors?) or I have to do trial & error... to find out how high in resistance I can go not to load the +5V PS). I can do it with two 2-5K Pot's. I wired all connections, incl. the +5V and ground from inside the Synth to a socket outside the Synth.
Another question to above circuit: This above circuit is needed 12 times (for 12 notes in MINOR and 12 notes in 7th) and to control this circuit via foot switch, I will have to connect all earthing resistors together. To separate them eletronically I'll need to insert diodes. Since it's to earth the cathodes have to be on the foot switch side... or?
Originally I thought to control that Live-Styler software with 4066 via the footpedal, but then I got into problems, because when I press the foot pedal all gates were flolating, causing a chorus... so, I worked out the above shown foot pedal circuit, which seems to be less complicated and better.

 

I translated the Live-Styler's manual (Ger-Eng) and the owner gave me a free copy of his software. On his pages I also left an instruction of how to convert a Synth keybd. to JANKO!!! http://www.live-styler.de/home/Janko Project.pdf
Together with the accordion accompaniment I'll have the easiest to learn & play Synth in the world! Check it out!
How to reward you? Chances are you like my talent, since I like yours? My electronic knowledge only consists of observations, suffered shocks and burned parts...
How to reward you? Chances are you like my talent, since I like yours? http://www.live-styler.de/home/images/jjj-DEMO.wma That's me twittering, there! I can also pay credit to your help in my Janko project PDF and mention this forum's name, for I don't believe in 'free meals'...