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The Fundamentals of Digital Potentiometers & How to Use Them

Buying or building computers for Hauptwerk, recommendations, troubleshooting computer hardware issues.
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engrssc

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The Fundamentals of Digital Potentiometers & How to Use Them

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NickNelson

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Re: The Fundamentals of Digital Potentiometers & How to Use

PostTue Jul 13, 2021 4:08 pm

The trouble with this sort of approach is that you have to:

1) measure/monitor the position of the swell pedal digitally
2) convert the digital position to a serial communication
3) have the 'digital pot' use the serial data to generate a voltage
4) send the voltage to an ADC in the MIDI encoder (just as before)

While this ought to be more reliable, and might be less noisy, than an analogue device I'm not sure it
would be worthwhile.

On the other hand I have considered (some time ago I admit) monitoring the position of a swell pedal
directly using an optically sensed 'Gray Code' approach and sending the parallel (four or five bit) digital data
to a microprocessor which is also doing the general MIDI encoding of pedals &c. I gave up on this eventually
due to the difficult of printing the code pattern and sensing the position sufficiently precisely given the usually
rather small arc the pedal moves through.

Nick
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engrssc

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Re: The Fundamentals of Digital Potentiometers & How to Use

PostTue Jul 13, 2021 8:27 pm

Just adding an occasional piece of info I find interesting as a base of overall Forum member's knowledge. These days we are totally surrounded (or can be) in some cool 8) tech details. Besides trying to learn more about Arduino, since my son just got a Model 3 Tesla, I'm finding that vehicle is right up there with amazing. :roll: But then, in a. different category, so is Hauptwerk - amazing that is. :lol: .

Rgds,
Ed
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davet

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Re: The Fundamentals of Digital Potentiometers & How to Use

PostWed Oct 13, 2021 5:41 pm

Hello All,
Thanks engrssc for the education on the digital potentiometer. I can use that I think for converting my Allen ADC6500. I also need to find if there are converters for the Allen keybrds to midi. These are a little strange since they have15 sets of 4 diodes and one for the number61 key. I don't think this is a common matrix.

Perhaps I may have to make a more drastic change in the printed circuit brd of the keybrd where the diode matrix is.
Anyway, the digital potentiometer will be a nice handy component to use in this project,
Thanks,
davet
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jkinkennon

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Re: The Fundamentals of Digital Potentiometers & How to Use

PostThu Oct 14, 2021 9:44 am

For davet, your Allen ADC 6500 keys and pedals make up a 16x16 matrix as a group. I did a Teensy 3.5 based encoder that monitored the keys on an ADC 7000 that was usable as a hybrid Allen/Hauptwerk console and will be happy to share details. My email is on the contact page of my website (below). Apologies for getting off topic here.

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