Modding A Pac-man Retro Light With Arduino

Made by RobSmithDev / Music / Retro Tech / Sensors

About the project

I'm modding nice Retro Pacman Light with an Arduino Nano to improve its functionality and effects including sound to light.

Project info

Difficulty: Moderate

Platforms: Arduino

Estimated time: 1 hour

License: Creative Commons Attribution-NonCommercial-ShareAlike CC BY-NC-SA version 4.0 or later (CC BY-NC-SA 4+)

Items used in this project

Hardware components

	Retro Pacman Light	x 1
	Arduino Nano R3	x 1

Software apps and online services

Arduino IDE

Story

So I've had this Pacman light for some time, but I don't really like the functionality it has. The main one being the sound to light effect requires the volume to be far too loud before it reacts,

In this video I show how the controller inside can be replaced with an Arduino, and then we re-program it to contain all the original effects and many more. The included code shows how to make a sound-to-light product that can even react to different sound frequencies.

Schematics, diagrams and documents

Final Circuit Diagram

Code

Final Code

// New Pacman Light Controller
// Created by RobSmithDev
// https://robsmithdev.co.uk
// https://www.youtube.com/c/RobSmithDev

#include <EEPROM.h>
#define FHT_N 256
#define LOG_OUT 1
#include <FHT.h>

#define PIN_GHOST_RED     3
#define PIN_GHOST_ORANGE  5
#define PIN_GHOST_BLUE    6
#define PIN_PACMAN        9

#define PIN_MODE_BUTTON   2

#define PIN_AUDIO_IN      A0

// Number of modes we support
#define MAX_MODES         7

enum Modes { mOff = 0, mOn = 1, mColourPhasing = 2, mPartyMode = 3, mVUMeter = 4, mRealVUMeter=5, mFrequencyMode=6 };

// A variable to store the current mode
volatile Modes mode = Modes::mOff;
volatile bool modeChanged = false;

// When the last loop occured, and the last time the mode was changed
unsigned long lastModeChange;

// Simple flag if audio is recording
bool isAudioRecording = false;

// We will record 256 samples and then take an average
unsigned char sampleCount = 0;
unsigned long totalCount;
unsigned short dcBiasLevel = 320;
unsigned short averageValue = 0;
unsigned short loudestValue = 0;
unsigned long lastCalculated;
volatile bool newSampleGroup = false;
unsigned char ghostPWMValue = 0;
unsigned char ghostPWMValueCounter = 0;

// Recorded samples
unsigned short samples[256];

// This function will execute then the button is pressed in.
void buttonPressInterruptHandler() {
  // You can use millis in an interrupt, but you cant stay in it too long.  
  // If this was pressed too recently, ignore it. Probably switch bouncing
  if (millis() - lastModeChange<450) return;
  lastModeChange = millis();

  // Go to the next mode
  modeChanged = true;
  mode = (Modes)((mode + 1) % MAX_MODES);
  EEPROM.put(0,(unsigned char)mode);
}

// Turns off everything
void turnOffEverything() {
  disableAudioRecording();
  analogWrite(PIN_GHOST_RED,0);
  analogWrite(PIN_GHOST_ORANGE,0);
  analogWrite(PIN_GHOST_BLUE,0);
  analogWrite(PIN_PACMAN,0);
  digitalWrite(PIN_GHOST_RED,LOW);
  digitalWrite(PIN_GHOST_ORANGE,LOW);
  digitalWrite(PIN_GHOST_BLUE,LOW);
  digitalWrite(PIN_PACMAN,LOW);  
}

void setup() {
  Serial.begin(9600);       // Start serial communication
  
  // put your setup code here, to run once:
  pinMode(PIN_GHOST_RED, OUTPUT);
  pinMode(PIN_GHOST_ORANGE, OUTPUT);
  pinMode(PIN_GHOST_BLUE, OUTPUT);
  pinMode(PIN_PACMAN, OUTPUT);

  pinMode(PIN_MODE_BUTTON, INPUT_PULLUP);
  pinMode(PIN_AUDIO_IN, INPUT);

  turnOffEverything();
  lastModeChange = millis();

  // Get the last mode we were on from EEPROM
  unsigned char lastMode;
  EEPROM.get(0, lastMode);
  mode = (Modes)lastMode;
  modeChanged = true;  
  attachInterrupt(digitalPinToInterrupt(PIN_MODE_BUTTON), buttonPressInterruptHandler, FALLING);
}

// Interrupt routine, that will run at 8khz for audio sampling
ISR(TIMER2_COMPA_vect) {
  // Capture and store
  unsigned int soundLevel = analogRead(PIN_AUDIO_IN);
  samples[sampleCount] = soundLevel;

  // Keep runnign total
  totalCount+=soundLevel;
  sampleCount++;

  if (sampleCount == 255) {
    // Maintain average (DC bias)
    dcBiasLevel = ((dcBiasLevel * 4) + (totalCount/256))  / 5; 
    sampleCount = 0;    
    totalCount = 0;
    loudestValue = 0;
    unsigned int total = 0;

    // Now look at the samples and see what was the loudest    
    for (unsigned char i=0; i<255; i++) {
      unsigned short volume;
      if (samples[i] < dcBiasLevel) 
        volume = dcBiasLevel - samples[i]; 
      else volume = samples[i] - dcBiasLevel;
      total += volume;    
    }

    loudestValue = (loudestValue + (total / 256)) / 2;
        
    // Continue to improve our average volume
    averageValue = ((averageValue * 10) + loudestValue) / 11;
    newSampleGroup = true;
  }
  lastCalculated = millis();

  // Manual PWM for the ghost seeing as we're using its PWM channel
  if (mode == Modes::mFrequencyMode) {
    ghostPWMValueCounter+=8;
    digitalWrite(PIN_GHOST_RED, ghostPWMValue>ghostPWMValueCounter);
  }
}

// Enable audio recording at 8khz.  This will prevent PWM working on the RED ghost, but we wont be using PWM
// See http://www.8bit-era.cz/arduino-timer-interrupts-calculator.html
void enableAudioRecording() {
  if (isAudioRecording) return;
  isAudioRecording = true;

  // Stop interrupts
  cli();
  TCCR2A = 0; // set entire TCCR2A register to 0
  TCCR2B = 0; // same for TCCR2B
  TCNT2  = 0; // initialize counter value to 0
  // set compare match register for 8000 Hz increments
  OCR2A = (F_CPU/(8 * 8000)) - 1; // (must be <256)
  // turn on CTC mode
  TCCR2B |= (1 << WGM21);
  // Set CS22, CS21 and CS20 bits for 8 prescaler
  TCCR2B |= (0 << CS22) | (1 << CS21) | (0 << CS20);
  // enable timer compare interrupt
  TIMSK2 |= (1 << OCIE2A);
  sei(); // allow interrupts
}

// ADCH
void disableAudioRecording() {
  if (!isAudioRecording) return;
  isAudioRecording = false;

  // Restore back to original 'Arduino' settings
  cli();
  TCCR2A = bit(WGM20);
  TCCR2B = bit(CS22);
  OCR2A = 0;
  OCR2B = 0;
  TIMSK2&=~bit(OCIE2A);                          // Disable interrupt
  sei(); // allow interrupts
}

// Run party mode
void doPartyMode(int speed, bool alwaysMinimum) {
  enableAudioRecording();

  // Dont update unless a new sample has been received.  Very dynamic!
  static unsigned int lastCalc = 0;
  if (lastCalc == lastCalculated) return;
  lastCalc = lastCalculated;

  static bool isAnimationRunning = false;
  static unsigned int target = 0;
  static unsigned int current = 0;

  if (!isAnimationRunning) {
      const unsigned int averageToBeat = (averageValue+4);
      if (loudestValue > averageToBeat) {
        target = (loudestValue - averageToBeat) * 2.5 * speed;
        if (target > 25 * speed) target = 25 * speed;
      } else {
        target = 0;
      }
      isAnimationRunning = true;
  } else {
    if (current < target) current++;
    if (current > target) current--;
    if (current == target) isAnimationRunning = false;
  
    digitalWrite(PIN_GHOST_RED, (current > 5*speed) || ((alwaysMinimum) && (loudestValue>(averageValue+8))));
    digitalWrite(PIN_GHOST_ORANGE, current > 10*speed);
    digitalWrite(PIN_GHOST_BLUE, current > 15*speed);
    digitalWrite(PIN_PACMAN, current > 20*speed); 
  }  
}

// A real vu meter, this one DOES NOT use auto volume gain
void doRealVU() {
    enableAudioRecording();

    // Dont update unless a new sample has been received.  Very dynamic!
    static unsigned int lastCalc = 0;
    if (lastCalc == lastCalculated) return;
    lastCalc = lastCalculated;

    digitalWrite(PIN_GHOST_RED, loudestValue>10);
    digitalWrite(PIN_GHOST_ORANGE, loudestValue>15);
    digitalWrite(PIN_GHOST_BLUE, loudestValue>20);
    digitalWrite(PIN_PACMAN, loudestValue>25); 
}

// Run a fequency mode.  Uses the ArduinoFHT library from http://wiki.openmusiclabs.com/wiki/ArduinoFHT
// You can install the library from the Arduino IDE but this didnt work for me, so I unzipped and copied the FHT folder to C:\Program Files (x86)\Arduino\hardware\arduino\avr\libraries
void runFrequencyMode() {
    enableAudioRecording();

    // Update when a new sample has been received
    static unsigned int lastCalc = 0;
    if (lastCalc == lastCalculated) return;
    lastCalc = lastCalculated;
      
    static unsigned int movingAverage[4] = {0,0,0,0};
    static unsigned int totals[4] = {0,0,0,0};
    static unsigned int fading[4] = {0,0,0,0};

    // Update when 256 samples have been received
    if (newSampleGroup) {
      cli();
      newSampleGroup = false;
      // To compute the FFT first we need the samples in a better format
      for (unsigned int s=0; s<255; s+=2) {
         fht_input[s] = samples[s];
         fht_input[s+1] = 0;
      }
      // Window the data
      fht_window();
      // Re-order the data
      fht_reorder();
      // Run the FHT process
      fht_run();
      // extract the data
      fht_mag_log();
      sei();
     
      // vReal between 0 and 127 contains a strength of frequency at that point.  We're gonna pull out some frequencies
      for (unsigned char a=0; a<32; a++) {
        totals[0] += fht_log_out[a];
        totals[1] += fht_log_out[a+16];
        totals[2] += fht_log_out[a+32];
        totals[3] += fht_log_out[a+48];
      }
  
      // Now maintain a moving average level for these
      for (unsigned char a=0; a<4; a++) {
        totals[a] /=32;  // get average of this group of bucket
        movingAverage[a] = (movingAverage[a] + totals[a]) /2;
        if (totals[a]>(movingAverage[a]+2)) fading[a] = 255;
      }
    }

    // Now light up the relevant light depending on what was detected    
    // The PWM channel for the ghost is in use by the interrupt. So we manually perform a PWM
    ghostPWMValue = fading[0];
    analogWrite(PIN_GHOST_ORANGE, fading[1]);
    analogWrite(PIN_GHOST_BLUE, fading[2]);
    analogWrite(PIN_PACMAN,fading[3]);

    for (unsigned char a=0; a<4; a++)
      if (fading[a]>2) fading[a]-=3;
}

void loop() {  
  
  // Be able to control the current mode via the serial port, starting at mode 0 for off
  if (Serial.available()) {
    unsigned char c = Serial.read();
    if ((c>='0') && (c<='9')) {
      mode = (Modes)(c-'0');
      modeChanged = true;
      EEPROM.put(0,(unsigned char)mode);
    }
  }  

  unsigned long tmp;
  switch (mode) {

    // Mode 0: Off
    case Modes::mOff: 
         turnOffEverything();
         break;

    // Mode 1: Fade in
    case Modes::mOn:
        if (modeChanged) {
          modeChanged = false;
          turnOffEverything();
          for (unsigned char brightness=0; brightness<255; brightness++) {
              analogWrite(PIN_GHOST_RED, brightness);
              analogWrite(PIN_GHOST_ORANGE, brightness);
              analogWrite(PIN_GHOST_BLUE, brightness);
              analogWrite(PIN_PACMAN, brightness); 
              delay(5);
          }
        }
        break;   

    // Mode 2: Colour phasing
    case Modes::mColourPhasing:
         if (modeChanged) {
            modeChanged = false;
            turnOffEverything();
         }         
         tmp = (millis() / 1000) % 3;
         analogWrite(PIN_GHOST_RED, (tmp == 0) ? 255 : 0);
         analogWrite(PIN_GHOST_ORANGE, (tmp == 1) ? 255 : 0);
         analogWrite(PIN_GHOST_BLUE, (tmp == 2) ? 255 : 0);
         analogWrite(PIN_PACMAN, 255); 
         break;

     case Modes::mPartyMode:
          if (modeChanged) {
            modeChanged = false;
            turnOffEverything();
            enableAudioRecording();
          }

          doPartyMode(10, false);
          
          break;

     case Modes::mVUMeter:
          if (modeChanged) {
            modeChanged = false;
            turnOffEverything();
            enableAudioRecording();
          }
          doPartyMode(4, true);          
          break;          

    case Modes::mRealVUMeter:
          if (modeChanged) {
            modeChanged = false;
            turnOffEverything();
            enableAudioRecording();
          }
          doRealVU();          
          break;      

    case Modes::mFrequencyMode:
          if (modeChanged) {
            modeChanged = false;
            turnOffEverything();
            enableAudioRecording();
          }
          runFrequencyMode();          
          break;      
  }
}

Credits

RobSmithDev

create software for Windows, and electronics for a variety of projects. Known for the DrawBridge and FloppyBridge project that brought real-time floppy disk access to Amiga emulators. I also build other electronics, software and games for Windows, Android, iOS, Amiga, Escape Room Systems, Digital Signage and more! Twitter: #robsmithdev https://www.patreon.com/RobSmithDev https://robsmithdev.co.uk https://amiga.robsmithdev.co.uk https://rcescapes.co.uk

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Modding A Pac-man Retro Light With Arduino

About the project

Project info

Items used in this project

Hardware components

Software apps and online services

Story

Schematics, diagrams and documents

Final Circuit Diagram

Code

Final Code

Credits

RobSmithDev

Leave your feedback...

Shop

Project Hub

Video

Blog

Shop home

3D printing

Single Board Computers

Development kits

Sensors

Internet of things

Robotics

Accessories

Product of the Week

Electromaker Educator

The Electromaker Show

The Electromaker Podcast

Modding A Pac-man Retro Light With Arduino

About the project

Project info

Items used in this project

Hardware components

Software apps and online services

Story

Schematics, diagrams and documents

Final Circuit Diagram

Code

Final Code

Credits

RobSmithDev

Leave your feedback...

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