Pot filtering help


#1

I have connected a 10k lin pot, via a 4067 16 channel multiplexer.

Im powering my nano via the pc over usb.

Filtering:
I multiply the analog in by 20, just to get a good readout with decimals, to read pot reading stability
And at the extreme pot point (closed and slowly moving up from there), i get a pretty jumpy value between 0 and 2,5. Other pot locations seem pretty solid. It only seems to be the low end values of the pot that are exteremly jumpy.
Could this be a psu thing? Or maybe i need to solder in a cap somewhere between each pot output connection to the multiplexer?

I can do filtering in XOD, in the sense that i could apply low pass filtering, but my logic tells me that this wont fix the 0-2,5 problem, only small jittery things (which is also needed).
How would i go about solving jitter? something like a slew limiter/portamento/lag processor/low pass filter is needed, but there doesnt seem to be anything like that available. How would i go about making one in xod?

I am a noob:)

Thanks!


Multiplexing with 74HC4067
#2

The jumpy values at low end are probably due to cheaper POT. You could use the debounce node to reduce the jitter. But if it is constantly changing at low end, you may never be able to get a 0 reading with debounce. Note that timer on debounce node is in seconds; you can get <1 sec by using fractional values like 0.5


#3

make some changes in the library, I think it’s clearer now, sorry

for the value use map

for filters I can not help you, @gweimer has given you an idea that can help you


#4

Thanks gweimer and cesars.
Cesars, i actually understood your old version better, so i think i will be using that:)


#5

@gweimer seems like the non-boolean debouncer is broken. When i open up the node, there is no code inside. The boolean works though, but not usable for me. It will probably be fixed in the future i guess.


#6

@the19thbear

Have a look here:

Perhaps this can help you meanwhile.


#7

Thanks. I’ll look into it.


#8

Ok. It seems like its filtering out the decimals in a good way. Still not tracking good at lower pot values, but as said, thats probably a cheap pot. Thanks!