4051 multiplexer work with encoders?

Hardware Development
1

Hi Folks,

I have a daisy pod for prototyping and would like to address 8 or more encoders with push button shafts. Each one will need 3 digital connections, if I understand correctly. That’s at least 24 total.

I have had a look at how the 4051 analog multiplexer can be used to address 8 potentiometers.
I assume this would not work for encoders as they are digitally addressed. Or would it with some sort of tweaking?/ I dunno.

Is there a method available to extend the number of encoders like the 4051 does for Pots?
Is there some way of doing it practically with SPI/I2C or something else?

I would like to keep this all managed by the Daisy pod if possible but I am aware a solution would be to use some other micro controller to do this and possibly connect the daisy to it through I2C or SPI. Also, Midi is a workable solution but I am researching an idea for a eurorack module so the expectation is the knobs should be on the eurorack module directly.

Oh, and I will be making multiples of these eurorack modules if the idea works, so a cost effective solution is needed.

I welcome any input on this.

Cheers,

Trevor

2

Texas Instruments (TI) makes a nice port expander chip: TCA8418RTWR
it connects via I2C, and can do either 18 direct digital inputs or scan up to 80 keys in an array (not sure if that would work for encoders, but there may be a way).

3

Also some people have mentioned the pcf8573

4

I Googled ‘multiplexing encoders’, this was the top result:

Worth reading, I think.

5

Thanks! I’ll look into it. My local supplier has an Adafruit breakout board for this.

6

Cool - thanks, there is an adafruit breakout for this too.

7

@tele_player Very good reference - thanks.
I get the feeling a multiplexer device might be OK for the 8 encoders I will start out with but I might to hit a scalability limit significantly beyond that. The mcp2307 is mentioned and has Arduino libraries so I think I will look into that too.