Color sensor TCS34725 relay switching

Other Hardware Sensors
1

Hello,
I would like to create a code based on the TCS34725 color sensor. The goal in that the sensor detects a color and switches a relay based on that. I already have the basic code running on my Arduino Uno, and can see the R,G,B values.

#include <Wire.h>
#include "Adafruit_TCS34725.h"

// Pick analog outputs, for the UNO these three work well
// use ~560  ohm resistor between Red & Blue, ~1K for green (its brighter)
#define redpin 3
#define greenpin 5
#define bluepin 6
// for a common anode LED, connect the common pin to +5V
// for common cathode, connect the common to ground

// set to false if using a common cathode LED
#define commonAnode true

// our RGB -> eye-recognized gamma color
byte gammatable[256];


Adafruit_TCS34725 tcs = Adafruit_TCS34725(TCS34725_INTEGRATIONTIME_50MS, TCS34725_GAIN_4X);

void setup() {
  Serial.begin(9600);
  //Serial.println("Color View Test!");

  if (tcs.begin()) {
    //Serial.println("Found sensor");
  } else {
    Serial.println("No TCS34725 found ... check your connections");
    while (1); // halt!
  }

  // use these three pins to drive an LED
#if defined(ARDUINO_ARCH_ESP32)
  ledcAttachPin(redpin, 1);
  ledcSetup(1, 12000, 8);
  ledcAttachPin(greenpin, 2);
  ledcSetup(2, 12000, 8);
  ledcAttachPin(bluepin, 3);
  ledcSetup(3, 12000, 8);
#else
  pinMode(redpin, OUTPUT);
  pinMode(greenpin, OUTPUT);
  pinMode(bluepin, OUTPUT);
#endif

  // thanks PhilB for this gamma table!
  // it helps convert RGB colors to what humans see
  for (int i=0; i<256; i++) {
    float x = i;
    x /= 255;
    x = pow(x, 2.5);
    x *= 255;

    if (commonAnode) {
      gammatable[i] = 255 - x;
    } else {
      gammatable[i] = x;
    }
    //Serial.println(gammatable[i]);
  }
}

// The commented out code in loop is example of getRawData with clear value.
// Processing example colorview.pde can work with this kind of data too, but It requires manual conversion to 
// [0-255] RGB value. You can still uncomments parts of colorview.pde and play with clear value.
void loop() {
  float red, green, blue;
  
  tcs.setInterrupt(false);  // turn on LED

  delay(60);  // takes 50ms to read

  tcs.getRGB(&red, &green, &blue);
  
  tcs.setInterrupt(true);  // turn off LED

  Serial.print("R:\t"); Serial.print(int(red)); 
  Serial.print("\tG:\t"); Serial.print(int(green)); 
  Serial.print("\tB:\t"); Serial.print(int(blue));

//  Serial.print("\t");
//  Serial.print((int)red, HEX); Serial.print((int)green, HEX); Serial.print((int)blue, HEX);
  Serial.print("\n");

//  uint16_t red, green, blue, clear;
//  
//  tcs.setInterrupt(false);  // turn on LED
//
//  delay(60);  // takes 50ms to read
//
//  tcs.getRawData(&red, &green, &blue, &clear);
//  
//  tcs.setInterrupt(true);  // turn off LED
//
//  Serial.print("C:\t"); Serial.print(int(clear)); 
//  Serial.print("R:\t"); Serial.print(int(red)); 
//  Serial.print("\tG:\t"); Serial.print(int(green)); 
//  Serial.print("\tB:\t"); Serial.print(int(blue));
//  Serial.println();


#if defined(ARDUINO_ARCH_ESP32)
  ledcWrite(1, gammatable[(int)red]);
  ledcWrite(2, gammatable[(int)green]);
  ledcWrite(3, gammatable[(int)blue]);
#else
  analogWrite(redpin, gammatable[(int)red]);
  analogWrite(greenpin, gammatable[(int)green]);
  analogWrite(bluepin, gammatable[(int)blue]);
#endif
}

Would you guys be willing to help me with this? I myself am having trouble figuring out how to build this.

Thanks in advance!

2

You will find that the RGB output, when pointing the sensor at a surface of given color, depends very strongly on the lighting conditions.

Your plan will have to take that variation into account, so it would be best to experiment for a bit, before deciding on a strategy.

Many people find the HSV (Hue Saturation Value) or HSL color systems much more convenient than RGB for this purpose.

3

The RGB values are nicely stable. Also the intention is to always have the same light intensity, so that is not a problem.
My question is, how do I switch 3 different relays (red,green,blue) based on RGB value from the sensor.
Thanks in advance for the help.

4

If statements come to mind.

if (red >= some_value) red_relay_on();

5

It has already succeeded, ChatGPT helped me get a good code.

#include <Wire.h>
#include <Adafruit_TCS34725.h>

#define RELAY_RED_PIN 2
#define RELAY_GREEN_PIN 3
#define RELAY_BLUE_PIN 4

Adafruit_TCS34725 tcs = Adafruit_TCS34725(TCS34725_INTEGRATIONTIME_50MS, TCS34725_GAIN_4X);

uint16_t redThreshold = 500;
uint16_t greenThreshold = 300;
uint16_t blueThreshold = 300;

void setup() {
  pinMode(RELAY_RED_PIN, OUTPUT);
  pinMode(RELAY_GREEN_PIN, OUTPUT);
  pinMode(RELAY_BLUE_PIN, OUTPUT);

  digitalWrite(RELAY_RED_PIN, HIGH); // Turn off relay initially
  digitalWrite(RELAY_GREEN_PIN, HIGH); // Turn off relay initially
  digitalWrite(RELAY_BLUE_PIN, HIGH); // Turn off relay initially

  Serial.begin(9600);

  if (tcs.begin()) {
    Serial.println("Found color sensor");
  } else {
    Serial.println("Color sensor not found");
    while (1);
  }
}

void loop() {
  uint16_t r, g, b, c;

  tcs.getRawData(&r, &g, &b, &c);

  if (r > redThreshold && r > g && r > b) {
    digitalWrite(RELAY_RED_PIN, HIGH); // Turn on red relay
    digitalWrite(RELAY_GREEN_PIN, LOW); // Turn off green relay
    digitalWrite(RELAY_BLUE_PIN, LOW); // Turn off blue relay
    Serial.println("Red detected");
  } else if (g > greenThreshold && g > r && g > b) {
    digitalWrite(RELAY_GREEN_PIN, HIGH); // Turn on green relay
    digitalWrite(RELAY_RED_PIN, LOW); // Turn off red relay
    digitalWrite(RELAY_BLUE_PIN, LOW); // Turn off blue relay
    Serial.println("Green detected");
  } else if (b > blueThreshold && b > r && b > g) {
    digitalWrite(RELAY_BLUE_PIN, HIGH); // Turn on blue relay
    digitalWrite(RELAY_RED_PIN, LOW); // Turn off red relay
    digitalWrite(RELAY_GREEN_PIN, LOW); // Turn off green relay
    Serial.println("Blue detected");
  } else {
    digitalWrite(RELAY_RED_PIN, LOW); // Turn off red relay
    digitalWrite(RELAY_GREEN_PIN, LOW); // Turn off green relay
    digitalWrite(RELAY_BLUE_PIN, LOW); // Turn off blue relay
  }
  delay(100);
}

Anyway, thanks for thinking with me.

6

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