This is a quick adobe rendering of what I want to do. I'm sure the color and placement might change a little but you get the idea of what I'm trying to do.
What blows my mind is nothing like this exist. There is one project I could find where someone added a Slide Potentiometer to a keyboard but it used 2 usbs. My goal is to have 1 usb that controls both the keyboard and the Slide Potentiometer.
So my question. Is there a single Arduino product that could handle mechanical keyboard inputs and 1-2 Slide Potentiometer ?
Nice picture but what do you mean "control" the sliders?
It will be about 100 times cheaper to use a regular USB keyboard and another USB for the Arduino which has the custom buttons and sliders. If you really only have 1 USB on the target computer then buy a small hub.
When you look for left sided mechanical keyboards you find this.
I don't want that. I want the arrow keys on the right side and the numpad on the left. You can obtain this with a detachable numpad but most of the reviews complain the numpad keys not registering due to a poorly designed layout.
Now to the volume slider. I'm a huge music geek and I love the feel of the Slide Potentiometer. Also because I'm a music geek I have all 10 usbs on my motherboard used. I've tried using numerous hubs as you've mentioned before and due to that many usbs being utilized + the hub things didn't function properly. This is why I want to keep it to 1 usb.
I typed in Arduino keyboard and most of them yield pictures like this.
This makes me think that the Arduino will pretty much be maxed out just due to the keyboard wires.
The way to minimize the IO pins necessary is with a matrix arrangement. That way you can use m+n IO lines to sense m*n individual switches.
There are some complications to that though. The upturned matrix shown in your post has 48 keys. The arrangement that uses the least amount of IO lines is to create a 7x7 matrix, which would require 14 lines and have the ability to sense 49 switches (so one extra spot is left over). However, the keys are physically arranged into a 12x4 matrix, so for that sake of convenience that is how they were connected. This requires 12+4 IO lines, 2 extra. As you might imagine, wiring up a physical 12x4 matrix to be 7x7 electrically would take some creativity, so in that specific case it's probably not worth it.
Things are different as the numbers go up and the arrangements get weirder. A 110 key keyboard could cover all its switches most efficiently* using a 11x10 matrix (21 lines, 110 elements). However, a keyboard is not arranged into neat columns and rows. Wiring a neat matrix array on top of the staggered rows and separated groups is going to be quite a feat.
Generally speaking, a matrix uses the lowest amount of lines when m and n are as close to equal as possible.
Can you daisy chain Ardiuno and still only use 1 usb?
You can have multiple slave devices communicating with a single master, and have the master act as the USB interface. That can get complicated though.
