Raspberry Pi 5 pin layout:


(Outer Edge of Pi)
    (+ 3.3V)    Pin  1  [x] [x]  Pin  2    (+ 5V)
    (I2C SDA)   Pin  3  [x] [x]  Pin  4    (+ 5V)
    (I2C SCL)   Pin  5  [x] [x]  Pin  6    (GND)
                Pin  7  [x] [x]  Pin  8 
         (GND)  Pin  9  [x] [x]  Pin 10 
                Pin 11  [x] [x]  Pin 12 
                Pin 13  [x] [x]  Pin 14    (GND)
                Pin 15  [x] [x]  Pin 16 
    (+ 3.3V)    Pin 17  [x] [x]  Pin 18 
                Pin 19  [x] [x]  Pin 20    (GND)
                Pin 21  [x] [x]  Pin 22    (GPIO 25 / INT)
                Pin 23  [x] [x]  Pin 24 
         (GND)  Pin 25  [x] [x]  Pin 26 
                Pin 27  [x] [x]  Pin 28 
                ... (continues to 40) …


MCP23017 I/O Expander Pin Layout:

+-----\_/-----+
            GPB0 |  1       28 | GPA0
            GPB1 |  2       27 | GPA1
            GPB2 |  3       26 | GPA2
            GPB3 |  4       25 | GPA3
            GPB4 |  5       24 | GPA4
            GPB5 |  6       23 | GPA5
            GPB6 |  7       22 | GPA6
            GPB7 |  8       21 | GPA7
      (+)    VDD |  9       20 | INTA   (Interrupt)
      (-)    VSS | 10       19 | INTB   (Interrupt)
              NC | 11       18 | RESET  (+)
 (Clock)     SCL | 12       17 | A2     (-)
 (Data)      SDA | 13       16 | A1     (-)
              NC | 14       15 | A0     (-)
                 +-------------+



Push Rotary Encoder Pin Layout:

(Rotational Side)
      [ Pin A ]  [ GND ]  [ Pin B ]
          |        |        |
        =======================
        |                     |
        |    ENCODER DIAL     |
        |                     |
        =======================
               |       |
            [ SW ]   [ GND ]
         (Push-Button Side)


Tactile Push Button Pin Layout:

(Internally linked)         (Internally linked)
           [ Pin A ] . . . . . . . . . [ Pin C ]
               |                           |
             =================================
             |                               |
             |           [ BUTTON ]          |
             |                               |
             =================================
               |                           |
           [ Pin B ] . . . . . . . . . [ Pin D ]