t3486784401 • Posted by vany5921

Published April 26, 2020 © MIT

Color recognition piano

TCS3472 color recognition module can distinguish different colors of objects, and map the colors to pitch through algorithm

IntermediateFull instructions provided2 hours1,647

Things used in this project

Hardware components

M5Stack Color Unit

M5Stack ESP32 Basic Core IoT Development Kit

Software apps and online services

Arduino IDE

Story

TCS3472 color recognition module can distinguish different colors of objects, and map the colors to pitch through algorithm, which is called "color controlled electronic piano".

In practice, the original expression of color is in the form of cie-rgb component, which is a three-dimensional space;

The brightness can be removed by transformation (see evaluation post ා (1)), and the chromaticity, cie-xyz, can be obtained, and the dimension can be reduced to two-dimensional space;

However, the actual pitch is one-dimensional linear, so it is necessary to reduce the cie-xyz dimension again through the algorithm to obtain the corresponding pitch in one-dimensional space.

After the hardware is built, software programming begins. The main framework of the program is Arduino UNO,

The Adafruit_TCS34725 class is used to access the sensor, and tone / ntone is used to generate pitch.

This paper focuses on the algorithm from cie-xyz space to pitch, as shown in the figure below.

In cie-xyz color space, the (x, y) coordinate relative to the white point is converted to the polar coordinate ρ ∠φ by me, that is

x= ρcosφy= ρsinφ

After conversion, ρ corresponds to the key strength, and φ corresponds to the key pitch. regulations:

When ρ is close to zero, it doesn't make a sound, that is, gray white corresponds to silent, and only when the color is bright enough can "play" the pitch.

When ρ is large enough, φ (0-360) will look up the table to correspond to one-dimensional pitch, and different colors will play different pitch notes.

Due to the smoothness of TCS3472 (see evaluation post 2), many different pitches can be called up.

The debugging information of serial port is embedded in the software. When working, the serial port can directly check the ρ and φ data for fine tuning.

// ColorTune: A TCS3472 based Musical Equipment

#include <M5Stack.h>
#include <Adafruit_TCS34725.h>
#include <math.h>
#include "CIE_Types.h"
#include "BUZ_Pitches.h"

/* Connect SCL    to analog 5
   Connect SDA    to analog 4
   Connect VDD    to 3.3V DC
   Connect GROUND to common ground */

/* Initialise with default values (int time = 2.4ms, gain = 1x) */
/* Initialise with specific int time and gain values */
// Available intervals:
// TCS34725_INTEGRATIONTIME_2_4MS
// TCS34725_INTEGRATIONTIME_24MS
// TCS34725_INTEGRATIONTIME_50MS
// TCS34725_INTEGRATIONTIME_101MS
// TCS34725_INTEGRATIONTIME_154MS
// TCS34725_INTEGRATIONTIME_700MS
Adafruit_TCS34725 tcs = Adafruit_TCS34725(TCS34725_INTEGRATIONTIME_24MS, TCS34725_GAIN_1X);

// Global Vars
static CIE_XYZ  g_OrigXY(0, 0);

//---------------------------------------------------------
// Chromaticity Proc.
//---------------------------------------------------------
CIE_XYZ GetCieXY(const CIE_RGB & rgb)
{
	// CIERGB to CIEXYZ
	double X = (2.7688 * rgb.r) + (1.7517 * rgb.g) + (1.1301 * rgb.b);
	double Y = (1.0000 * rgb.r) + (4.5906 * rgb.g) + (0.0601 * rgb.b);
	double Z = /*(0 * r) + */ (0.0565 * rgb.g) + (5.5942 * rgb.b);
	double S = X+Y+Z;
	return CIE_XYZ(X/S, Y/S);
}

//---------------------------------------------------------
// Music Proc.
//---------------------------------------------------------
void PlayNote(float phi)
{
	// Play a note, guided by phi(0~360)
	uint16_t tmp= (uint16_t)(phi+0.5);
	if(tmp<70)			  M5.Speaker.tone(NOTE_C5);
	else if(tmp<90)		M5.Speaker.tone(NOTE_D5);
	else if(tmp<130)	M5.Speaker.tone(NOTE_E5);
	else if(tmp<180)	M5.Speaker.tone(NOTE_F5);
	else if(tmp<225)	M5.Speaker.tone(NOTE_G5);
	else if(tmp<250)	M5.Speaker.tone(NOTE_A5);
	else if(tmp<315)	M5.Speaker.tone(NOTE_B5);
	else				M5.Speaker.tone(NOTE_C6);
}

void StopPlay(void)
{
	M5.Speaker.mute();;
}

//---------------------------------------------------------
// Arduino Proc.
//---------------------------------------------------------
void setup(void)
{
	M5.begin();
	Serial.begin(115200);
  M5.Lcd.setCursor(20, 0, 2);
	// TCS3472 Init
	if (!tcs.begin())
	{
		Serial.println("TCS34725: Failed ... check connections");
		while (1);
	}
	Serial.println("TCS34725: OK");
	delay(100);

	// Get Average ORIG position
	CIE_XYZ sum(0,0);
	#define NUM_AVERAGE		10
	for(uint8_t i=0; i<NUM_AVERAGE; i++)
	{
		CIE_RGB rgb;
		tcs.getRawData(&rgb.r, &rgb.g, &rgb.b, &rgb.c);
		sum+= GetCieXY(rgb);
	}
	sum/= NUM_AVERAGE;
	g_OrigXY= sum;
	M5.Lcd.print("ORIG: ");
	M5.Lcd.print(g_OrigXY.x, 3);
	M5.Lcd.print(", ");
	M5.Lcd.print(g_OrigXY.y, 3);
	M5.Lcd.println();

	// Now we're ready to get readings!
}

void loop(void)
{
	// Get Current Color (CIE_XYZ)
	CIE_RGB rgb;
	tcs.getRawData(&rgb.r, &rgb.g, &rgb.b, &rgb.c);
	CIE_XYZ xy= GetCieXY(rgb);
	xy-= g_OrigXY;							// Abs -> Rel

	// Convert (x,y) to Rho<Phi
	float rho= sqrt(xy.x*xy.x +xy.y*xy.y);		// Radius
	float phi= atan2(xy.y, xy.x) *(180/M_PI);	// Angle(-180~+180, Valid when Radius>0)
	if(phi<0) phi+= 360;					// Angle(0~+360)

	// When it is Colorful, Do something
	#define THR_COLORFUL	0.03			// Colorful Threshold
	if(rho>THR_COLORFUL)
	{
		// It is colorful
		PlayNote(phi);						// Play a Note
    M5.Lcd.setCursor(20, 20, 2);
		M5.Lcd.print("(Colorful): ");
		M5.Lcd.println(phi, 1);
	}
	else
	{
		// It is white or gray
		StopPlay();							// Stop Play(=Mute)
    M5.Lcd.setCursor(20, 40, 2);
		M5.Lcd.print("(Gray)");
		static uint8_t cnt= 0;
		M5.Lcd.println(cnt++, HEX);		// For Debug Effect
	}
}

/*************************************************
 * Public Constants
 *************************************************/

#ifndef __BUZ_PITCHES_H__
#define __BUZ_PITCHES_H__

#define NOTE_B0  31
#define NOTE_C1  33
#define NOTE_CS1 35
#define NOTE_D1  37
#define NOTE_DS1 39
#define NOTE_E1  41
#define NOTE_F1  44
#define NOTE_FS1 46
#define NOTE_G1  49
#define NOTE_GS1 52
#define NOTE_A1  55
#define NOTE_AS1 58
#define NOTE_B1  62
#define NOTE_C2  65
#define NOTE_CS2 69
#define NOTE_D2  73
#define NOTE_DS2 78
#define NOTE_E2  82
#define NOTE_F2  87
#define NOTE_FS2 93
#define NOTE_G2  98
#define NOTE_GS2 104
#define NOTE_A2  110
#define NOTE_AS2 117
#define NOTE_B2  123
#define NOTE_C3  131
#define NOTE_CS3 139
#define NOTE_D3  147
#define NOTE_DS3 156
#define NOTE_E3  165
#define NOTE_F3  175
#define NOTE_FS3 185
#define NOTE_G3  196
#define NOTE_GS3 208
#define NOTE_A3  220
#define NOTE_AS3 233
#define NOTE_B3  247
#define NOTE_C4  262
#define NOTE_CS4 277
#define NOTE_D4  294
#define NOTE_DS4 311
#define NOTE_E4  330
#define NOTE_F4  349
#define NOTE_FS4 370
#define NOTE_G4  392
#define NOTE_GS4 415
#define NOTE_A4  440
#define NOTE_AS4 466
#define NOTE_B4  494
#define NOTE_C5  523
#define NOTE_CS5 554
#define NOTE_D5  587
#define NOTE_DS5 622
#define NOTE_E5  659
#define NOTE_F5  698
#define NOTE_FS5 740
#define NOTE_G5  784
#define NOTE_GS5 831
#define NOTE_A5  880
#define NOTE_AS5 932
#define NOTE_B5  988
#define NOTE_C6  1047
#define NOTE_CS6 1109
#define NOTE_D6  1175
#define NOTE_DS6 1245
#define NOTE_E6  1319
#define NOTE_F6  1397
#define NOTE_FS6 1480
#define NOTE_G6  1568
#define NOTE_GS6 1661
#define NOTE_A6  1760
#define NOTE_AS6 1865
#define NOTE_B6  1976
#define NOTE_C7  2093
#define NOTE_CS7 2217
#define NOTE_D7  2349
#define NOTE_DS7 2489
#define NOTE_E7  2637
#define NOTE_F7  2794
#define NOTE_FS7 2960
#define NOTE_G7  3136
#define NOTE_GS7 3322
#define NOTE_A7  3520
#define NOTE_AS7 3729
#define NOTE_B7  3951
#define NOTE_C8  4186
#define NOTE_CS8 4435
#define NOTE_D8  4699
#define NOTE_DS8 4978

#endif

// CIE_Types: Define CIE_RGB & CIE_XYZ

#ifndef __CIE_TYPES_H__
#define __CIE_TYPES_H__

// CIE_RGB Data Type
typedef class _CIE_RGB
{
public:					// Vector & Constructor
	uint16_t  r,g,b,c;	// RGB & Clear
	_CIE_RGB(uint16_t _r= 0, uint16_t _g= 0, uint16_t _b= 0) {r=_r; g=_g; b=_b; c=0;}
public:					// Operators
	_CIE_RGB & operator=(const _CIE_RGB & val) {r=val.r; g=val.g; b=val.b; c=val.c; return *this;}
} CIE_RGB;

// CIE_XYZ Data Type
typedef class _CIE_XYZ
{
public:					// Vector & Constructor
	float  x, y;
	_CIE_XYZ(float _x= 0, float _y= 0) {x=_x; y=_y;}
public:					// Operators
	_CIE_XYZ & operator=  (const _CIE_XYZ & val) {x=val.x; y=val.y; return *this;}
	_CIE_XYZ & operator+= (const _CIE_XYZ & val) {x+=val.x; y+=val.y; return *this;}
	_CIE_XYZ & operator-= (const _CIE_XYZ & val) {x-=val.x; y-=val.y; return *this;}
	_CIE_XYZ & operator*= (const float val) {x*=val; y*=val; return *this;}
	_CIE_XYZ & operator/= (const float val) {x/=val; y/=val; return *this;}
	bool       operator== (const _CIE_XYZ & val) {return x==val.x && y==val.y;}
	bool       operator== (const float val) {return x==val && y==val;}
} CIE_XYZ;

#endif

Credits

t3486784401

Posted by

vany5921

Color recognition piano

Things used in this project

Hardware components

Software apps and online services

Story

Code

Hardware connected

BUZ_Pitches.h

CIE_RGB & CIE_XYZ

Credits

Comments

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Color recognition piano

Color recognition piano

Things used in this project

Hardware components

Software apps and online services

Story

Code

Hardware connected

BUZ_Pitches.h

CIE_RGB & CIE_XYZ

Credits

Comments

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