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Hall sensors

Building organ consoles for use with Hauptwerk, adding MIDI to existing consoles, obtaining parts, ...
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Coenraads

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Re: Hall sensors

PostSun Jun 20, 2021 6:35 pm

This is interesting, and may explain the jitter on pin 69.

"The ATmega datasheet also cautions against switching analog pins in close temporal proximity to making A/D readings (analogRead) on other analog pins. This can cause electrical noise and introduce jitter in the analog system. It may be desirable, after manipulating analog pins (in digital mode), to add a short delay before using analogRead() to read other analog pins."

And guess what? I am using pin 68 as a digital input with pull-up resistor! Will have to try the time delay.
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andrewmorley

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Re: Hall sensors

PostMon Jun 21, 2021 1:32 pm

It’s pin 66 I’m using
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andrewmorley

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Re: Hall sensors

PostMon Jun 21, 2021 2:38 pm

Ok so the problem of the controller messages has been solved thanks to grounding the unused analogue inputs so thank you for that solution. Now I have the slightly strange situation of my swell pedal working the wrong way round.
The problem with the intermittent pedal notes sorted itself momentarily then I switched my demon amp on and it started again. Is there maybe electrical interference from my amp? It keeps doing it once the amp is off but I guess it retains some kind of electrical charge.
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larason2

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Re: Hall sensors

PostMon Jun 21, 2021 2:44 pm

A lot of the problems you’re having are exactly the same problems I had when I started my Arduino project. Initially, I wanted to interface with the Allen keying system, but I had so many anomalous Midi messages I had to give up. I also went through numerous iterations of the code for note and potentiometer input so they would be noiseless. How you wire them up is also important. Here is the write up I did of my work on the Arduino Hub. Without looking at the code and schematic, it’s really hard to point out problems, so if you could provide us with those, it would be helpful.

https://create.arduino.cc/projecthub/Larason2/midi-for-digital-organs-f3756c?ref=platform&ref_id=424_trending___&offset=6

For the swell pedal, either you can invert the mapping in the arduino code, or swap the 5V and the ground wired to the potentiometer.
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engrssc

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Re: Hall sensors

PostTue Jun 22, 2021 7:55 am

Any further up to date changes ?

Rgds,
Ed
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NickNelson

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Re: Hall sensors

PostThu Jun 24, 2021 12:07 am

If the problem is jitter, this discussion may be of help:

viewtopic.php?f=15&t=15799&p=118619&hilit=truncation#p118619

Nick
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engrssc

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Re: Hall sensors

PostThu Jun 24, 2021 2:30 am

As "another way to do it", you might want to check out this Midi Hardware board which has in addition to 64 keyboard (switch) inputs, 8 inputs foe pots (expression pedals - not sure if I've seen an organ with this many) and 7 special switch inputs all individually user configurable.


https://www.midi-hardware.com/index.php?section=prod_info&product=MBBS&R2=USD

One nice feature is the 64 keyboard inputs can be configured to operate in the split mode where each "half" can operate indecently as to MIDI channel for instance. This board is very easy to set up as well as being very small. Another feature is that this board is stand alone i.e. not requiring a Master Controller.

As a slightly less expensive but with less features is

https://www.midi-hardware.com/index.php?section=prod_info&product=BBS-1K&R2=USD

BTW, I use this board (in the split configuration) to connect up to 32 drawknobs - with half of the inputs configured to send "note on" and the other half to send "note off" (both on the same MIDI channel.)

Along with a MIDECO board to control 64 LED's if drawknobs are lighted.

[url].https://www.midi-hardware.com/index.php ... ECO&R2=USD[/url]

or 32 - SAMs using an additional:

https://www.midi-hardware.com/index.php?section=prod_info&product=MIBO&R2=USD

Rgds,
E
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andrewmorley

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Re: Hall sensors

PostSat Jun 26, 2021 3:04 pm

No further updates I’m afraid. The random controller messages are solved but the pedal on/offs are still intermittent. I’m going to try balancing the transformer inputs into the various boards and see if that works as I wonder if it might be a voltage thing. Failing that I will look at the code for the arduino and see if that might solve things.
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NickNelson

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Re: Hall sensors

PostSat Jun 26, 2021 3:15 pm

andrewmorley wrote:I’m going to try balancing the transformer inputs into the various boards and see if that works as I wonder if it might be a voltage thing.


Transformers???
Neither MIDI or controller inputs should have anything to do with them.
Unless you mean the DC supplies I suppose, which ought to be well regulated.
Continuous controller potentiometers will always benefit from bypass capacitors across the + and ground
connections.

Nick
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andrewmorley

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Re: Hall sensors

PostSat Jun 26, 2021 4:58 pm

My apologies maybe I’ve used the wrong terminology. I mean the thing I plug into the wall that provides power for my encoder.
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andrewmorley

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Re: Hall sensors

PostThu Jul 01, 2021 10:25 am

Thank you everyone for your advice. I though I would do an update, and having read through all the replies there’s a few details folk have asked about which I haven’t provided. So:

1. The random controller messages has been solved by grounding the unused analogue inputs.

2. The sensors are still producing constant on/off messages. I have tried using the same voltage of 12v albeit different power power supply’s which had different wattage and amps. Still no joy so I ordered one ☝️ f the recommended power supplies for arduino mega from PiHut which works at 9v so I made sure I set the supply to the keymux to 9v too. This gave me an error message saying that a device was trying to draw too much power and disabled the midi from the arduino. So I am at a loss!

In answer to questions
a) I am using a Mac mini running Mac OS High Sierra 10.13.6
b) Audio is via Scarlett Focusrite
c) I am testing midi signals using MidiView
d) Hall Sensors and keymux64 are from MidiBoutique
e) Encoder is an Elegoo Mega from MidiKits and I will attempt to post the code into my next reply!

Hoping someone has some brain waves as I am stumped!
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larason2

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Re: Hall sensors

PostThu Jul 01, 2021 8:30 pm

The constant on/off messages are probably because of the Keymux64 encoder. Given that it powered, it probably scans the inputs from the board, then provides outputs that are timed to be in sync with the HWCE2. However, the Arduino may well read the pins at a different timing than the Keymux64 board is putting out. So, if the Arduino reads the pins, and the Keymux64 doesn’t have them activated at the time, it will read them off, whereas if they are activated, it will read them on. If you attach the Keymux64 pins to an oscilloscope, you can figure out the timing, then you’ll have to reprogram the arduino to match.
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andrewmorley

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Re: Hall sensors

PostSat Jul 03, 2021 6:08 pm

Do you think I’d be better off getting a much more straightforward scanmatrix and can anyone suggest one? It would need to take 32 inputs from the hall sensors
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engrssc

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Re: Hall sensors

PostSat Jul 03, 2021 8:08 pm

andrewmorley wrote:Encoder is an Elegoo Mega from MidiKits and I will attempt to post the code into my next reply


I haven't been able to find any information on the Elegoo Mega from MidiKits??
You need to provide more details - model, specifications, link, code. Is this encoder to connect to a matrix? If so, which configuration?

Are you using the Midi Boutique keymux64 for the manuals or a pedalboard conversion?

Which supplier for the Hall sensors?

Rgds,
Ed
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larason2

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Re: Hall sensors

PostSun Jul 04, 2021 12:11 am

You can wire the hall sensors directly to an arduino mega. However, if you’re not handy with the coding, I recommend you buy either the Midi boutique board that was originally intended to interface with the hall sensor kit (best option), or buy a HWCE2 kit to work with the Keymux64 boards. The problem with the second option is it is much more expensive, and you aren’t guaranteed that the problem isn’t how the keymux64 boards are interpreting the hall sensor array data.
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