There is one thing I have noticed that I think is the reason why Hall sensors aren't used in commercial musical keyboards design.
As it turned out during experiments, Hall sensors are susceptible to electromagnetic field (no surprise here really...
Yes I thought I needed extra protection, but then I checked 4067 analog multiplexer data sheet. https://www.ti.com/lit/ds/symlink/cd4067b.pdf
Every input is protected internally (see below) and since I am using Vdd=3.3V supply for the analog...
OK, my calculations above are off by factor of 4.7 because I have 1kΩ resistor in series after multiplexer so actual time constant is 63ns and time required to charge ADC capacitor would be 1.4µs , but this does not change the fact that with 62...
Thank you for showing so much interest in my project! It is really appreciated!
To quickly answer some of your most important questions:
1. I am currently using neodymium magnets with diameter of 6 mm and thickness of 2 mm. No I did not...
@Pio I just wanted to say that this is one of the most amazing projects on this forum. Congratulations!
I am watching your progress, since some years ago I did a prototype of guitar FX box using STM32F401 which is nowhere near to Teensy 4 in...
Yes I noticed that. I am now thinking why it is so, but on the other hand it doesn't bother me that much, as I am using threshold to detect pressed key and currently I have set note-on threshold at level 2000, so it is far far away from any...
Yesterday I wired the keyboard to the controller and found one tiny error in the printed circuit. After fixing it I wrote the program that simply reads
the Hall sensor values from all 48 sensors using three channel ADC and analog multiplexers on...
This is such a cool project. I'm also in the business of refurbishing an old keyboard - in my case, giving a toy keyboard with rubber dome switches nicer-feeling mechanical switches. Still only on/off. However, I've realised using hall effect...
That is even better. With (1/distance^3) interference between keys is much lower. And with very close distance to one of the poles (when key is pressed and one pole of the magnet nearly touches the sensor), I got more of 1/distance^2...
I wasn't aware of organforum. Thanks for the pointer. Before I wrote first post, I already made experiments with few keys. I am using really small magnets that are specifically selected to minimize effects of magnet interference. Magnetic drag...
Since there are so many synth projects on this forum, yet just a few talk about controllers for synths, I would like to introduce you to one of the projects I've been working on for some time... and I'm trying to motivate myself to finish it...
Some advice on FX. The usual order of FX section is that they are connected one after another (serial, not parallel setup as in your scheme) and reverb comes last. Flanger/chorus first. With your current parallel setup, the reverb would only be...