Connecting a color sensor to an Arduino is a great way to add color sensing capabilities to your Arduino projects. With a color sensor, your Arduino can detect and differentiate between different colors. This allows you to build projects that can react to different colored objects, detect color changes, sort objects by color, and more.
In this article, we will go over everything you need to know to connect a color sensor to an Arduino. We will cover the materials needed, how to wire it up, install required libraries, and program the Arduino to read color data from the sensor. Let’s get started!
Required Materials
To follow along with this article, you will need the following materials:
| Arduino Uno or compatible board |
| Color sensor – TCS34725 or similar |
| Breadboard |
| Jumper wires |
| 4.7K ohm resistor |
The color sensor we will use is the TCS34725 which can detect color ranges of RGB as well as color temperature. Other similar color sensors like the TCS34725 breakout board will also work.
Wiring the Color Sensor
We need to connect four pins from the TCS34725 to the Arduino – power, ground, SDA and SCL. Here is the wiring diagram:
| TCS34725 Pin | Arduino Pin |
| 3.3V | 3.3V |
| GND | GND |
| SCL | A5 |
| SDA | A4 |
In addition to the above, we need to connect a 4.7K pull-up resistor between the SDA line and 3.3V. This is required for reliable I2C communication.
Once wired up, it should look something like this:
Be sure to triple check your connections before powering on your Arduino!
Installing the Arduino Library
For the Arduino to get color data from the TCS34725 sensor, we need to install a special library. For this sensor, we will be using the Adafruit TCS34725 library. Here are the installation steps:
1. Download the Adafruit TCS34725 library from GitHub: https://github.com/adafruit/Adafruit_TCS34725
2. Unzip the downloaded file.
3. In the Arduino IDE, click Sketch > Include Library > Add .ZIP Library
4. Select the .ZIP file you downloaded and the library will be installed.
5. Restart the Arduino IDE.
Now we can begin coding using the TCS34725 library!
Reading Raw Color Data
Let’s start by reading raw red, green, blue (RGB) color data from the sensor. Here is an example sketch:
“`cpp
#include
#include “Adafruit_TCS34725.h”
Adafruit_TCS34725 tcs = Adafruit_TCS34725(TCS34725_INTEGRATIONTIME_700MS, TCS34725_GAIN_1X);
void setup() {
Serial.begin(9600);
if (tcs.begin()) {
Serial.println(“Found sensor”);
} else {
Serial.println(“No TCS34725 found … check your connections”);
while (1);
}
}
void loop() {
uint16_t r, g, b, c, colorTemp, lux;
tcs.getRawData(&r, &g, &b, &c);
Serial.print(“R: “); Serial.print(r); Serial.print(” “);
Serial.print(“G: “); Serial.print(g); Serial.print(” “);
Serial.print(“B: “); Serial.print(b); Serial.print(” “);
Serial.println();
delay(500);
}
“`
This will initialize the sensor, then continuously read the RGB values and print them to the Serial monitor. The raw values will be between 0-65535.
We can also get the color temperature and lux (brightness) values:
“`cpp
tcs.getRawData(&r, &g, &b, &c);
colorTemp = tcs.calculateColorTemperature(r, g, b);
lux = tcs.calculateLux(r, g, b);
“`
Detecting Color Name
While raw RGB values are useful, often we want to determine the detected color name. We can add a function to our code to translate the RGB values into a color name:
“`cpp
// Function to detect color name from RGB values
String detectColor(uint16_t r, uint16_t g, uint16_t b) {
// Check if red dominates
if (r > g && r > b) {
return “Red”;
}
// Check if green dominates
else if (g > r && g > b) {
return “Green”;
}
// Check if blue dominates
else if (b > r && b > g) {
return “Blue”;
}
// Detect white
else if (r > 500 && g > 500 && b > 500) {
return “White”;
}
// Detect black
else if (r Setting Color Thresholds
Instead of just printing the color name, we can use thresholds to take action when a certain color is detected:
“`cpp
if (colorName == “Red”) {
// Turn on red LED
}
else if (colorName == “Green”) {
// Play green sound
}
else if (colorName == “Blue”) {
// Flash blue light
}
“`
Thresholds allow your Arduino to react to different color objects uniquely.
Calibrating Sensor Readings
The raw sensor values can vary a lot depending on ambient light levels. We can calibrate the readings to account for this.
Add this near the top:
“`cpp
#define RED_DARK 200
#define GREEN_DARK 300
#define BLUE_DARK 150
“`
Then when getting readings:
“`cpp
uint16_t red = r – RED_DARK;
uint16_t green = g – GREEN_DARK;
uint16_t blue = b – BLUE_DARK;
“`
This subtracts the ambient light levels so just the object color is detected. Tweak the threshold values as needed.
Troubleshooting Issues
Here are some common issues and solutions when using the color sensor:
| Issue | Solution |
| No data from sensor | Check wiring connections |
| Incorrect color detected | Tweak RGB threshold values |
| Unstable readings | Add calibration to subtract ambient light |
| Library not found error | Re-install sensor library |
Some other things to try:
– Adjust the integration time and gain settings
– Try different color objects
– Check if your power supply is providing steady 3.3V
– Check if the pull-up resistor is correctly wired
With some tweaking, you should be able to get consistent color detection from the sensor.
Example Projects
Here are just a few example projects you can create using an Arduino color sensor:
Color Sorter
Sort LEGO bricks or Skittles candy by color! Detect object color and use a servo to sort into bins.
Produce Ripeness Checker
Detect ripe fruit and vegetables by looking for color changes from green to red/yellow. Useful for automated farming.
Color Matching Game
Flash different colors and have user try to match by placing correct object over sensor. Great for kids.
Mood Lighting
Detect shirt color and change RGB LED to complement it. For example, green shirt = purple light.
Color Mixing Lamp
Scan two objects and blend the RGB values to create a custom color lamp effect.
The possibilities are endless! What will you build?
Conclusion
Connecting a color sensor to your Arduino opens up many exciting project opportunities. In this article we covered:
– The components needed including the TCS34725 sensor
– How to wire up the sensor to Arduino
– Installing the required library
– Reading raw RGB, color temperature and light level data
– Detecting color names from RGB values
– Applying thresholds to take action on certain colors
– Calibrating readings to account for ambient light
– Troubleshooting common issues
– Example projects you can create
With this foundation you should be able to add full color sensing capabilities to your Arduino projects. Have fun experimenting with the color sensor!
