Controlling analog hardware - project


#1

Hi.
I have an analog device with multiple switches and pots that i would like to control digitally, and by doinig that, adding preset capability.
I want to be able to store the pot values, have a preset bank, and load different values (pretty much got this working as well, thanks to bradzilla84’s preset library).
My plan i to use the arduino along with XOD+4067 multiplexers.
I will solder off the pots, from the analog device’s curcuit board and connect them to inputs on the multiplexers, thereby digitizing the values. (this i have pretty much working thanks to cesars 4067 multiplexer library). Then, by using output multiplexers (demultiplexer?), i want to be able to send the values out from the arduino and connect it to the input pins, where the pots used to be connected to the circuit board.

The output part, of this project, I have not done yet.

I’m assuming i need some type of sample and hold circuit between each output from the demultiplexer and the input on the analog devices cicruit board? Because when the demultiplexer is outputting to the next output, no value is being output to the first output.
How would you go about that?
Is this something that is readily available? I would need quite a bit of ins/outs, so a “package” solution with many S/H circuits would be preferrable.

This is all just a hobby project, but would be cool if I could succeed:)

Thanks


#2

74HC4067 does not work for you, you need a demultiplexer with latch type 74HC4351
or increase the multiplexing speed


#3

Ok. I’m assuming the latch function is so that no sample/hold circuit is needed.
Can I use your amazing multiplexer library for this, even though it doesnt have matching numbers? (4351).
I’ll buy one and experiment:)


#4

It can operate as 4051, should read the datasheet
How the latch works.
The frequency of multiplexing must be high, you have to test the maximum, you can not use a frequency of 1hz, because the first value will come out and the last one after 48sec


#5

Ok. Thanks. Just bought one, and will report back:)


#6

Would this work instead?
https://www.mouser.dk/Analog-Devices-Inc/Semiconductors/Switch-ICs/Multiplexer-Switch-ICs/ADG527A-Series/Datasheets/_/N-7590d?P=1yye72dZ1yyh4l4
its 16 channels, instead of 8.


#7

It’s a multiplexer, it does not work for you, you need a demultiplexer


#8

Ah, i thought it could do both things.


#9


??
Would like to use a 16 channel instead of 8 channel, as i might run out of arduino ports.


#10

it’s not analog, it’s digital logic


#11

Argh… haha. Will look further