is reverse Multiplexing possible?

I have a few CD4051s and a few CD4067s

With an analog multiplexer i can take multiple signals that control or can be controlled by one analog signal into or from an arduino.

My question is...is it possible to run one signal into a multiplexer and use a digital signal to control multiple pin connections between the arduino and the multiplexer?

I am building a Midi controller and need to assign multiple controls to a single potentiometer. I would like to wire corresponding buttons that will change the "Bank" of a Pot. When the button is pressed the Mux switches to the respective pin so the same Pot now controls a different arduino analog pin.

Figured this would be much easier than reassigning midi values

That's an Analog Ssitch application.. Look up CD4016 analog swtch.

Yes it is possible but it is stupid to do so.
This is because the output is only valid while it is being addressed.
What you need is a chip called an addressable latch, that is very similar but keeps a constant output when not being addressed.

Unless I misunderstood the OP, he is only interested in the output that is being addressed at any given moment and doesn't care about the banks that are not selected. I don't know if that design will work without more information.

Hi, you don't need an external multiplexer chip or to use multiple analog inputs to achieve what you describe. It can all be done in your sketch with the pot wired to a single analog input, and your bank switches wired to other digital inputs.

Multiplexing and demultiplexing are techniques used to allow you to do more with fewer resources. What you seem to be describing is doing less with more resources! :wink:

Paul

is reverse Multiplexing possible

Yes, it's called Demultiplexing. There are Multiplexers and Demultiplexers.

I think a schematic would help but you need to clarify whether or not you need latches . I don't think you have clarified that.

sonnystikz:
When the button is pressed the Mux switches to the respective pin so the same Pot now controls a different arduino analog pin.

Seems to me the OP is proposing to connect the same pot to one of several Arduino analog inputs via a multiplexer. The multiplexer is controlled by the Arduino based on the setting of some "bank" buttons, also connected (directly or indirectly) to the Arduino. If I have understood correctly, this would be a waste of several Arduino analog inputs, a waste of several Arduino digital outputs (which would control the multiplexer) and a waste of a multiplexer and any latches. Simply connect the pot to a single analog input and read the value into one of several variables (maybe an array) depending on the setting of the bank switches.

sonnystikz:
Figured this would be much easier than reassigning midi values

I don't know much about MIDI, so don't understand this part, so maybe I have misinterpreted the entire proposed circuit?

Is there any point in further speculation without a schematic ?

I dont have a schematic yet but i will post one soon-

but i'll try to clarify my overall problem.....

I am creating a midi Mixer for use with software apps like FL Studio

Fl studio has 99 mixer channels- each has 3 assignable knobs, a volume fader, a stereo spread knob, a pan knob and 8 effect volume knobs

I would like to control all of these functions using a small number of physical mixer channels,.

ex. 10 total mixer channels each has one fader, 8 effect knobs and 3 eq knobs, when you press a corresponding bank button you can control 1-10, 11-20...etc

so I need each control to permanently be assigned to a number of different functions
so knob 1 controls the pan for channels 1, 11, 21.....etc
I wouldn't need the other outputs to be addressed since I would only be using the knob for the currently assigned bank-

I figured if i demux the knob and spread the analog signal i could achieve this-

raschemmel:
Unless I misunderstood the OP, he is only interested in the output that is being addressed at any given moment and doesn't care about the banks that are not selected. I don't know if that design will work without more information.

you are correct

PaulRB:
Hi, you don't need an external multiplexer chip or to use multiple analog inputs to achieve what you describe. It can all be done in your sketch with the pot wired to a single analog input, and your bank switches wired to other digital inputs.

Multiplexing and demultiplexing are techniques used to allow you to do more with fewer resources. What you seem to be describing is doing less with more resources! :wink:

Paul

Well i need tons of Pots, so if i could Mux a pot into a de mux both 4067s then ideally i'd have 16 pots going into 1 analog channel- only one usable at a time of course.... but will it work?

then ideally i'd have 16 pots going into 1 analog channel- only one usable at a time of course

Here is an example of having 16 inputs (you can use pots) going into 2 analogue inputs. With the right multiplexer you can just use one chip.
http://www.thebox.myzen.co.uk/Hardware/MIDI_Footsteps.html

Grumpy_Mike:

then ideally i'd have 16 pots going into 1 analog channel- only one usable at a time of course

Here is an example of having 16 inputs (you can use pots) going into 2 analogue inputs. With the right multiplexer you can just use one chip.
MIDI Footsteps

follow me for a sec........... one pot...16 different positions/pins = 15 "Virtual" pots

I have a sample schematic but where can i upload it?

At the bottom of the reply box is a triangle saying "Additional Options".

Click the "Additional Optioins" link in the lower left of the screen and select "Browse for file"

follow me for a sec........... one pot...16 different positions/pins = 15 "Virtual" pots

If you had "Virtual Pots" you would need to "SET" each pot and read the setting into an array that can be read back using an index.

raschemmel:
If you had "Virtual Pots" you would need to "SET" each pot and read the setting into an array that can be read back using an index.

im not too familiar with arrays and indexes

Here is a sample schematic for the basic Idea i have- I wanna take a pot into a de-mux- then the de-mux channels into a mux and that analog out into the arduino.

The purpose -- each mux input channel can be assigned to a bank- so when i read channel 0 on the mux (not de-mux)
the pot will control bank 1 parameter, channel 1 on the mux will control bank 2...etc

I can assign push switches to change the banks

inv mux sample.jpg