Return to Question

This is the schematic, a "dirty sketch":

This is the schematic, a "dirty sketch":

I'll provide the schematic if anyone wants

This is the schematic, a "dirty sketch":

/*cols and rows*/
byte rows[] = {2,3,4,5};
const int row_Count = 4; 
byte cols[] = {6,7,8,9,10,14,15,16,18,19,20,21};
const int col_Count = 12;

byte keyboard[col_Count][row_Count];

void read_layout() {
    /*do the columns*/
    for (int col_Index=0; col_Index < col_Count; col_Index++) {
        /*setup for registering the column state*/
        byte cur_Col = cols[col_Index];
        pinMode(cur_Col, OUTPUT);
        digitalWrite(cur_Col, LOW);
 
        /*do the rows*/
        for (int row_Index=0; row_Index < row_Count; row_Index++) {
            byte row_Col = rows[row_Index];
            pinMode(row_Col, INPUT_PULLUP);
            keyboard[col_Index][row_Index] = digitalRead(row_Col);
            pinMode(row_Col, INPUT);
        }
        /*disable the column*/
        pinMode(cur_Col, INPUT);
    }
}
 
void print_layout() {
    for (int row_Index=0; row_Index < row_Count; row_Index++) {
        Serial.print(row_Index); 
        Serial.print(F(": "));
 
        for (int col_Index=0; col_Index < col_Count; col_Index++) {  
            Serial.print(keyboard[col_Index][row_Index]);
            if (col_Index < col_Count) Serial.print(F(", "));
        }   
        Serial.println("");
    }
    Serial.println("");
}

void setup() {
    Serial.begin(115200);
    delay(2000);
    /*init the rows*/
    for(int i=0; i<row_Count; i++) {
        pinMode(rows[i], INPUT);
    }
    /*init the cols*/
    for (int i=0; i<col_Count; i++) {
        pinMode(cols[i], INPUT_PULLUP);
    }     
}

void loop() {
    read_layout();
    print_layout();
            
}

/*cols and rows*/
byte rows[] = {2,3,4,5};
const int row_Count = 4; 
byte cols[] = {6,7,8,9,10,14,15,16,18,19,20,21};
const int col_Count = 12;

byte keyboard[col_Count][row_Count];

void read_layout() {
    /*do the columns*/
    for (int col_Index=0; col_Index < col_Count; col_Index++) {
        /*setup for registering the column state*/
        byte cur_Col = cols[col_Index];
        pinMode(cur_Col, OUTPUT);
        digitalWrite(cur_Col, LOW);
 
        /*do the rows*/
        for (int row_Index=0; row_Index < row_Count; row_Index++) {
            byte row_Col = rows[row_Index];
            pinMode(row_Col, INPUT_PULLUP);
            keyboard[col_Index][row_Index] = digitalRead(row_Col);
            pinMode(row_Col, INPUT);
        }
        /*disable the column*/
        pinMode(cur_Col, INPUT);
    }
}
 
void print_layout() {
    for (int row_Index=0; row_Index < row_Count; row_Index++) {
        Serial.print(row_Index); 
        Serial.print(F(": "));
 
        for (int col_Index=0; col_Index < col_Count; col_Index++) {  
            Serial.print(keyboard[col_Index][row_Index]);
            if (col_Index < col_Count) Serial.print(F(", "));
        }   
        Serial.println("");
    }
    Serial.println("");
}

void setup() {
    Serial.begin(115200);
    delay(2000);
    /*init the rows*/
    for(int i=0; i<row_Count; i++) {
        pinMode(rows[i], INPUT);
    }
    /*init the cols*/
    for (int i=0; i<col_Count; i++) {
        pinMode(cols[i], INPUT_PULLUP);
    }     
}

void loop() {
    read_layout();
    print_layout();
            
}