Digital Potentiometers - Short Circuits Episode3

[davidenelson]

WHERE CAN I BUY THIS PLEASE TELL ME!!

[apprenticemart2]

Are you going to show us how to do the same thing, but using and encoder?

[DIYGuitarMods]

This tutorial is so well done! Thanks so much. I've spent hours just trying to find out how digital pots are controlled via their inputs and this was very clear. I have a question which I hope is not too much trouble to answer but I understand if you are busy. Is it possible to use an analog pot to control this digital pot? If it is possible then could you possibly point me to some resources to learn. Cheers!

[daviddanielgraham]

Thank you so much! I am in my first year of building electronics, and I have a modular analog synthesizer that I am building, and I am attempting to interface the units to the computer and adjust the controls with a custom UI I am programming in C#. I have been struggling to understand how to replace the mechanical potentiometers in the circuits with digipots and this is the first tutorial-esque approach to DigiPots I have encountered. The information you have presented is quite useful.

[daviddanielgraham]

PS... Jerrie in this video you are using up/down with push buttons... If you were using a UART for serial interface for a large number of pots (100-ish) would you prefer Up/Down, SPI, or I^2C? Thanks in advance for reading my post. Happy Trails to you! :D

[1dosucol1]

Excellent stuff !Just what i was looking for,as i'm after a 3 gang linear pot,can't find them in the UK and i don't want to use 3 singles,o 3 small trimmers (1 behind the other,with a small rod going through each for adjustment.



[mirabilis]

Instant Remedy!

[fivefishdiy]

Is there "zipper" noise with the digital pot? Couldn't hear well with the audio.

[jeriellsworth]

@fivefishdiy Yes. There are limited steps.

[fivefishdiy]

@jeriellsworth Is there a way to make an audio zero-crossing detector so the digi-pot would only inc/dec at the point where the audio signal waveform is at zero?

[FlyByPC]

Neat component (and excellent explanation, as always). I guess the chip takes care of debouncing by a built-in time limit?

[ricky94533]

I just want to say that I'm in love with you @.@, ok beyond that, I just wanted to know how is this different from 3-wire? I needed 30k but it's super hard to find, I only found it in 3 wire, *hug*

[jeriellsworth]

@ricky94533 3 wire interfaces are handy for controlling by microcontroller.

[santiks]

it's a mono pot?

[jeriellsworth]

@santiks This one is. You can get different types.

[FlamingCuntLips]

Hi, any chance you can advise on how to get a programable potentiometer much like the sort on behringers V amp range or most midi controllers ?

neat diagrams it made a bit more sense than looking at a breadboard : )

[wayne205stevens]

Grand job lass, just what i was looking for! Thanks :)

[mjkirk12]

For audio, wouldn't audio taper (logarithmic) digipot give better control over an audio input?

[kinglonewolf104]

Thanks for the video. Now I know how potentiometers work :)

&eB

[superdau]

I understand that this is a "proof of concept". But the U/D input should be set at least 50ns before INC is pulled low for reliable operation. If both go low at the same time the U/D input could be undefined. Maybe the diode and the capacitance of the INC input create some kind of delay for INC, so it works in this setup. But I wouldn't rely on that.

[PhattyMo]

Cool!

I noticed on your drawing that you have the audio input on the wiper,and the output on the top end of the resistor.. I'm just wondering if there was a reason for that,because the 'usual' convention that I've seen is the opposite -audio input on top,and output taken from the wiper. take care!

[crackwitz]

*could* be just a mistake...

[PhattyMo]

Yea,could be..I was just curious if there was a particular reason or something.

[crackwitz]

when the "wiper" is "down", wiper--GND has no resistance, which *might* be inconvenient for the Audio-In.

also, in the shown configuration, Audio-In--GND has no constant resistance, so depending on where the "wiper" is, different currents flow through Audio-In.

also, Audio-Out would always be on the same potential as Audio-In, which would make the *depicted* config *useless*.

yeah, just mislabeled.

[jeriellsworth]

The drawing was reversed from what I had prototyped, but the reversed configuration still works.

Crackwitz I think you might have missed the series caps on the audio input which isolate the dc component of the audio.

[crackwitz]

right. i haven't done much of anything with AC circuits yet. gotta keep that in mind :)

[GRAHAMAUS]

@jeriellsworth Reverse configuration works, but it isn't "good". The audio input wants to see a reasonably constant impedance and definitely doesn't want to see a short to ground, series cap or not. Otherwise, a very nice little demo, thanks!

[jeriellsworth]

Been a while, since I made this and looked at the data sheet, but I seem to remember a variant that has built in op amp buffers.