TCS34725 Color Sensor

Other Hardware Sensors
1

I've got an Arduino nano wired to a TCS34725 color sensor, along with the proper library. I'm using the Adafruit TCS34725 colorview example and this video as a reference. The RGB LED lights up but all the colors at the same time, and it doesn't seem to be affected by any color you put in front of the sensor. I've triple-checked all the wiring and checked the serial monitor to make sure the sensor was actually seeing color. The RGB values change accordingly in the serial monitor, but for some reason, my nano isn't sending that info to the RGB LED.

2

47 posts and you forgot to post the code, using code tags?

my nano isn't sensing that info to the RGB LED

Did you mean sending?

3

I did mean sending, sorry, typed this on my phone earlier. Here is the code

#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
}
4

Things to check:

  1. Which Arduino "nano"?
  2. Are the pins used for the LED PWM pins on that "nano"?
  3. Make sure you can completely control the RGB LED using a simple, stand alone test program.
5
  • I'm using a Nano 3.0 by Lafvin.
  • I checked and the pins I used for the RGB LED are PWM pins.
  • I ran a simple RGB LED cycle program and it worked perfectly using the current pins.

I have no idea what else it could be if the sensor shows it is reading the colors properly, and the nano seems to work, what's keeping the LED from reflecting the changes? I would think maybe it's the program but I'm using the one in the video.

6

Put Serial.prints() in this code, to see what gammatable values are actually being sent to the pins.

  analogWrite(redpin, gammatable[(int)red]);
  analogWrite(greenpin, gammatable[(int)green]);
  analogWrite(bluepin, gammatable[(int)blue]);
7

So I've found the issue and got it to work. Apparently I don't know the difference between common cathode and anode LED. I changed this line to false and got it to work:

#define commonAnode true

Once again, thanks for your help!

8

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