Edit numpad input with arduino nano

Projects General Guidance
1

Hello everyone,
i start with the premise that it is the first time i take an arduino in hand, but i have knowledge of other programming languages. at the suggestion of a friend of mine who tried every now and then to do some small projects with arduino, i bought a nano.

I have a numpad(17 keys), which i would like to turn into a sort of macro keyboard (hid macros and other software do not meet my requirements).
With the help of my friend i cut the usb(usb A, i think 1.0) cable and it divided in 4 cables:
red 5v, black g, white d + and green d-
For the correspondence of the wires i based myself on what is written next to the welding on the chip.
So i connected red and black in their respective pins and then the white on d2 and green on d3.
At this point we wrote a small code just to find out what input the keyboard sent, and then begin to create the bindings of the keys

int testo;
int testo2;

void setup() {
Serial.begin(9600);
pinMode(2, INPUT);
pinMode(3, INPUT);
}

void loop() {
  testo = digitalRead(2);
  testo2 = digitalRead(3);
  delay(1000);
  Serial.write(testo);
  Serial.write("...");
  Serial.write(testo2);
}

Unfortunately, however, when i compile the arduino, on the serial monitor i have this output:

which continues to infinity even if i try to click any key on the numpad.

did i miss anything in the cable connection or in the code?

2

USB is a lot more complex than you hoped it would be.
What you should probably have done is use a USB host like this (assuming the keypad shows up as a HID keyboard when plugged into a PC).