Turn your NES controller into a simple 8 key electronic piano with this Instructable.

I was inspired to make this project after completing the Instructables Arduino Class, reading Gordon McComb's excellent book "Arduino Robot Bonanza" (www.robotoid.com), and building joshua.brook's Simple Electronic Piano.

Step 1: Parts and Equipment

1 x NES controller - I picked one up from my local pawnbroker / second hand store
1 x Arduino UNO or similar - I used a DuinoTECH Classic (UNO)
1 x Piezo Transducer - I used a DuinoTECH Arduino Compatible Active Buzzer Module
5 x Male-male jumper wires (Black, Red, Orange, Yellow, Green)
2 x Male-female jumper wires (Black, Blue)

Step 2: Connect Controller to Arduino

The NES controller plug has 7 pins - Click on the pins in the first picture to find each function

Connect red wire to +5V (NES pin 7) and 5V pin (Arduino) - Fortunately, male jumper wires fit perfectly into the NES controller plug
Connect black wire to GND (NES pin 1) and GND (Arduino)
Connect orange wire to Clock (NES pin 2) and D5
Connect yellow wire to Latch (NES pin 3) and D6
Connect green wire to DataIn (NES pin 4) and D7

Step 3: Connect Piezo Transducer Module

Connect female end of blue wire to S on Piezo Transducer Module and then to D9 (Arduino)
Connect female end of black wire to - on Piezo Transducer Module and then to GND (Arduino)

Step 4: NES Controller Piano Sketch

Download the sketch (see attached file)*.
Add the pitches.h library to a new tab in the sketch
Upload the sketch to your Arduino

*The sketch is based on Gordon McComb's "Teachbot gamepad controller sketch / TeachbotServo_NES.ino" from his brilliant book Arduino Robot Bonanza published by McGraw-Hill in 2013. Arduino Robot Bonanza is well worth the read and I found it complementary to Instructables' Arduino Class.

/* NES Controller Piano
 * 
 * Created 22 December 2018
 * 
 * This project turns a NES controller into a simple piezo buzzer piano
 * ----------------------------------------------------------------
 * Requires:
 * ----------------------------------------------------------------
 *  -   1 x Arduino Uno
 *  -   1 x Active Piezo Transducer Module
 *  -   5 x Male-Male Jumper Wires
 *  -   2 x Male-Female Jumper Wires
 *  -   1 x NES controller
 * -----------------------------------------------------------------
 * NES Controller Plug ("End On" View)
 * -----------------------------------------------------------------
 *                _________
 *                /      01     |GND
 *       +5V   	 |  70  02   |Clock
 *       ?       |  60  03  |Latch
 *       ?       |  50  04  |DataIn
 *               __________
 * -----------------------------------------------------------------
 * Connections:
 * -----------------------------------------------------------------
 * Arduino Uno Pinout     NES Controller 
 *                        (Use Male-Male Jumper Wires)
 * -----------------------------------------------------------------
 * +5V      ------------> Pin 7
 * D7       ------------> Pin 4
 * D5       ------------> Pin 2
 * D6       ------------> Pin 3
 * GND      ------------> Pin 1
 *------------------------------------------------------------------                        
 * Arduino UNO Pinout     Active Piezo Transducer Module 
 *                        (Use Male-Female Jumper Wires)
 * -----------------------------------------------------------------
 * D9       ------------> S
 * GND      ------------> GND
 * -----------------------------------------------------------------
 * NES Controller Button Values:
 * -----------------------------------------------------------------
 * Right  = 11111110  bit 0
 * Left   = 11111101  bit 1
 * Down   = 11111011  bit 2
 * Up     = 11110111  bit 3
 * Start  = 11101111  bit 4
 * Select = 11011111  bit 5
 * B      = 10111111  bit 6
 * A      = 01111111  bit 7
 * -----------------------------------------------------------------
 * Libraries Required: 
 * -----------------------------------------------------------------
 * "pitches.h" library (https://www.arduino.cc/en/Tutorial/toneMelody)
 * copy and paste to "New Tab" 
 * -----------------------------------------------------------------
 * Reference List:
 * -----------------------------------------------------------------
 * "Teachbot gamepad controller sketch" by Gordon McComb Arduino Robot Bonanza McGraw-Hill 2013
 */
 #include "pitches.h"   // include pitches library
 #define nesClock 5     // label pinout
 #define nesLatch 6
 #define nesDataIn 7
 #define buzzer 9
 byte nes = 0;         // global variable
 
void setup() {
  // put your setup code here, to run once:
Serial.begin (9600); // serial terminal speed 
pinMode (nesDataIn, INPUT); // set up pins
pinMode (nesClock, OUTPUT);
pinMode (nesLatch, OUTPUT);
pinMode (buzzer, OUTPUT);
}
void loop() {
  // put your main code here, to run repeatedly:
nes = nesRead ();
if (bitRead (nes, 0) == 0){ // If right button NES Controller pressed
  tone (buzzer, NOTE_F4, 250); // play tone NOTE_F4
  Serial.println ("NOTE_F4"); // NOTE_F4 displayed on Serial monitor
}
if (bitRead (nes, 1) == 0){
  tone (buzzer, NOTE_E4, 250);
  Serial.println ("NOTE_E4");
}
if (bitRead (nes, 2) == 0){
  tone (buzzer, NOTE_D4, 250);
  Serial.println ("NOTE_D4");
}
if (bitRead (nes, 3) == 0){
  tone (buzzer, NOTE_C4, 250);
  Serial.println ("NOTE_C4");
}
if (bitRead (nes, 5) == 0){
  tone (buzzer, NOTE_G4, 250);
  Serial.println ("NOTE_G4");
}
if (bitRead (nes, 4) == 0){
  tone (buzzer, NOTE_A4, 250);
  Serial.println ("NOTE_A4");
}
if (bitRead (nes, 6) == 0){
  tone (buzzer, NOTE_B4, 250);
  Serial.println ("NOTE_B4");
}
if (bitRead (nes, 7) == 0){
  tone (buzzer, NOTE_C5, 250);
  Serial.println ("NOTE_C5");
}
if (nes == 255) //Checks to see if no button pressed (255 = 11111111)
{
  noTone; //if no button pressed no tone will be played
  Serial.println ("NO_TONE"); 
}
delay (180);
}
byte nesRead (){ // "bit banging" 
  byte value = 0;
  digitalWrite (nesLatch, HIGH);
  delayMicroseconds(5);
  digitalWrite (nesLatch, LOW);
  for (int i=0; i<8; i++) {
    digitalWrite (nesClock, LOW);
    value |= digitalRead (nesDataIn) << (7 - i);
    digitalWrite (nesClock, HIGH);
  }
  return (value);
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