chaining Multiplexers and Shift registers over longer cables

Design Concepts
1

Hi there!

I would like to make several small midiboxes for differant purposes

that I can Stack and shuffle together according to the project I work on.

it would be cool to connect a differant physical controller for each VST I load in the host.

Anyway, thats the concept, here’s the question:

It would be a waste to make a brand new core for each module so,

could I have say a mother midibox with external 5 PIN DIN and AIN connectors?

If so, could I go as far as scattering SHIFT REGISTERS over say 5 meters of cable  or will I loose the clock?

Thanks for any ideas or comments

;D
chain.jpg

2

Hi mb944,

I can not recomment such long cables !

I once tested connection length from the DIN to the core.

Result: Everthing larger than 2 m causes random midi messages (I used flat cable).

Perhaps you have to use a shielded cable ?

I think 1 m between the shift registers should be no problem - test it !

I had the same problem. Now I use seperate Cores for each VST  :wink:

greets

Doc

3

One option to run digital (or analog) signals over a long cables is to use a differential transmission. You could try to implement a RS-422 communication between the core and the DIN. And then chain to the next DIN in the same way. RS-422 is digital, so this rules out the AIN, but if you can live with encoders is should be doable…Speed should not be a problem with this method.

Check out this http://www.epanorama.net/links/tele_interface.html#rs422

Another option is to build a couple of current loop transievers.

http://www.epanorama.net/links/tele_interface.html#currentloop

This is just my first thougts, have’t tryed them myself. Don’t know if this current method could handle the dataspeed from the core…

Sorry for my bad english…

/Henrik

4

hi!

thanks for the suggestions!

the easiest solution seems to me to just have the din and ain pins “pluggable” instead of the chips

ok, each button/pot/knob will need an individual wire, but I only had mini boxes in mind

thanks again for the support

Alex