Using a Color Sensor to Draw Picture

This post shows you how to detect colors with the Arduino using the TCS230/ TCS3200 color sensor .

The TCS3200 color sensor can detect a wide variety of colors based on their wavelength. This sensor is specially useful for color recognition projects such as color matching, color sorting, test strip reading and much more.

Introduction

The TCS3200 color sensor – shown in the figure below – uses a TAOS TCS3200 RGB sensor chip to detect color. It also contains four white LEDs that light up the object in front of it.

Specifications

Here's the sensor specifications:

Power: 2.7V to 5.5V
Size: 28.4 x 28.4mm (1.12 x 1.12″)
Interface: digital TTL
High-resolution conversion of light intensity to frequency
Programmable color and full-scale output frequency
Communicates directly to microcontroller

Where to buy?

You can check the TCS3200 or a TCS230 color sensor on Maker Advisor and find the best price.

How does the TCS3200 sensor work?

The TCS3200 has an array of photodiodes with 4 different filters. A photodiode is simply a semiconductor device that converts light into current. The sensor has:

16 photodiodes with red filter – sensitive to red wavelength
16 photodiodes with green filter – sensitive to green wavelength
16 photodiodes with blue filter – sensitive to blue wavelength
16 photodiodes without filter

If you take a closer look at the TCS3200 chip you can see the different filters.

By selectively choosing the photodiode filter's readings, you're able to detect the intensity of the different colors. The sensor has a current-to-frequency converter that converts the photodiodes' readings into a square wave with a frequency that is proportional to the light intensity of the chosen color. This frequency is then, read by the Arduino – this is shown in the figure below.

Pinout

Here's the sensor pinout:

Pin Name	I/O	Description
GND (4)		Power supply ground
OE (3)	I	Enable for output frequency (active low)
OUT (6)	O	Output frequency
S0, S1（1，2）	I	Output frequency scaling selection inputs
S2, S3（7，8）	I	Photodiode type selection inputs
VDD（5）		Voltage supply

Filter selection

To select the color read by the photodiode, you use the control pins S2 and S3. As the photodiodes are connected in parallel, setting the S2 and S3 LOW and HIGH in different combinations allows you to select different photodidodes. Take a look at the table below:

Photodiode type	S2	S3
Red	LOW	LOW
Blue	LOW	HIGH
No filter (clear)	HIGH	LOW
Green	HIGH	HIGH

Frequency scaling

Pins S0 and S1 are used for scaling the output frequency. It can be scaled to the following preset values: 100%, 20% or 2%. Scaling the output frequency is useful to optimize the sensor readings for various frequency counters or microcontrollers. Take a look at the table below:

Output frequency scaling	S0	S1
Power down	L	L
2%	L	H
20%	H	L
100%	H	H

For the Arduino, it is common to use a frequency scaling of 20%. So, you set the S0 pin to HIGH and the S1 pin to LOW.

Color Sensing with Arduino and TCSP3200

In this example you're going to detect colors with the Arduino and the TCSP3200 color sensor. This sensor is not very accurate, but works fine for detecting colors in simple projects.

Parts required

Here's the parts required for this project:

TCSP3200 or TCS230 color sensor
Arduino UNO – read Best Arduino Starter Kits
Jumper wires

You can use the preceding links or go directly to MakerAdvisor.com/tools to find all the parts for your projects at the best price!

Schematic

Wiring the TCSP3200 sensor to your Arduino is pretty straightforward. Simply follow the next schematic diagram.

Here's the connections between the TCSP3200 and the Arduino:

S0: digital pin 4
S1: digital pin 5
VCC: 5V
S3: digital pin 6
S4: digital pin 7
OUT: digital pin 8

Code

You need two sketches for this project:

Reading and displaying the output frequency on the serial monitor. In this part you need to write down the frequency values when you place different colors in front of the sensor.
Distinguish between different colors. In this section you'll insert the frequency values picked previously on your code, so that your sensor can distinguish between different colors. We'll detect red, green and blue colors.

1. Reading the output frequency

Upload the following code to your Arduino board.

          /*********   Rui Santos   Complete project details at https://randomnerdtutorials.com   *********/  // TCS230 or TCS3200 pins wiring to Arduino #define S0 4 #define S1 5 #define S2 6 #define S3 7 #define sensorOut 8  // Stores frequency read by the photodiodes int redFrequency = 0; int greenFrequency = 0; int blueFrequency = 0;  void setup() {   // Setting the outputs   pinMode(S0, OUTPUT);   pinMode(S1, OUTPUT);   pinMode(S2, OUTPUT);   pinMode(S3, OUTPUT);      // Setting the sensorOut as an input   pinMode(sensorOut, INPUT);      // Setting frequency scaling to 20%   digitalWrite(S0,HIGH);   digitalWrite(S1,LOW);       // Begins serial communication    Serial.begin(9600); } void loop() {   // Setting RED (R) filtered photodiodes to be read   digitalWrite(S2,LOW);   digitalWrite(S3,LOW);      // Reading the output frequency   redFrequency = pulseIn(sensorOut, LOW);       // Printing the RED (R) value   Serial.print("R = ");   Serial.print(redFrequency);   delay(100);      // Setting GREEN (G) filtered photodiodes to be read   digitalWrite(S2,HIGH);   digitalWrite(S3,HIGH);      // Reading the output frequency   greenFrequency = pulseIn(sensorOut, LOW);      // Printing the GREEN (G) value     Serial.print(" G = ");   Serial.print(greenFrequency);   delay(100);     // Setting BLUE (B) filtered photodiodes to be read   digitalWrite(S2,LOW);   digitalWrite(S3,HIGH);      // Reading the output frequency   blueFrequency = pulseIn(sensorOut, LOW);      // Printing the BLUE (B) value    Serial.print(" B = ");   Serial.println(blueFrequency);   delay(100); }

View raw code

Open the serial monitor at a baud rate of 9600.

Place a blue object in front of the sensor at different distances. You should save two measurements: when the object is placed far from the sensor and when the object is close to it.

Check the values displayed on the serial monitor. The blue frequency (B) should be the lowest compared to the red (R) and green (G) frequency readings – see figure below.

When we place the blue object in front of the sensor, the blue frequency (B) values oscillate between 59 and 223 (see highlighted values).

Note: you can't use these frequency values (59 and 223) in your code, you should measure the colors for your specific object with your own color sensor. Then, save your upper and bottom frequency limits for the blue color, because you'll need them later.

Repeat this process with a green and red objects and write down the upper and bottom frequency limits for each color.

2. Distinguish between different colors

This next sketch maps the frequency values to RGB values (that are between 0 and 255).

In the previous step when we have maximum blue we obtained a frequency of 59 and when we have blue at a higher distance we obtained 223.

So, 59 in frequency corresponds to 255 (in RGB) and 223 in frequency to 0 (in RGB). We'll do this with the Arduino map() function. In the map() function you need to replace XX parameters with your own values.

          /*********   Rui Santos   Complete project details at https://randomnerdtutorials.com   *********/  // TCS230 or TCS3200 pins wiring to Arduino #define S0 4 #define S1 5 #define S2 6 #define S3 7 #define sensorOut 8  // Stores frequency read by the photodiodes int redFrequency = 0; int greenFrequency = 0; int blueFrequency = 0;  // Stores the red. green and blue colors int redColor = 0; int greenColor = 0; int blueColor = 0;  void setup() {   // Setting the outputs   pinMode(S0, OUTPUT);   pinMode(S1, OUTPUT);   pinMode(S2, OUTPUT);   pinMode(S3, OUTPUT);      // Setting the sensorOut as an input   pinMode(sensorOut, INPUT);      // Setting frequency scaling to 20%   digitalWrite(S0,HIGH);   digitalWrite(S1,LOW);      // Begins serial communication   Serial.begin(9600); }  void loop() {   // Setting RED (R) filtered photodiodes to be read   digitalWrite(S2,LOW);   digitalWrite(S3,LOW);      // Reading the output frequency   redFrequency = pulseIn(sensorOut, LOW);   // Remaping the value of the RED (R) frequency from 0 to 255   // You must replace with your own values. Here's an example:    // redColor = map(redFrequency, 70, 120, 255,0);   redColor = map(redFrequency, XX, XX, 255,0);      // Printing the RED (R) value   Serial.print("R = ");   Serial.print(redColor);   delay(100);      // Setting GREEN (G) filtered photodiodes to be read   digitalWrite(S2,HIGH);   digitalWrite(S3,HIGH);      // Reading the output frequency   greenFrequency = pulseIn(sensorOut, LOW);   // Remaping the value of the GREEN (G) frequency from 0 to 255   // You must replace with your own values. Here's an example:    // greenColor = map(greenFrequency, 100, 199, 255, 0);   greenColor = map(greenFrequency, XX, XX, 255, 0);      // Printing the GREEN (G) value     Serial.print(" G = ");   Serial.print(greenColor);   delay(100);     // Setting BLUE (B) filtered photodiodes to be read   digitalWrite(S2,LOW);   digitalWrite(S3,HIGH);      // Reading the output frequency   blueFrequency = pulseIn(sensorOut, LOW);   // Remaping the value of the BLUE (B) frequency from 0 to 255   // You must replace with your own values. Here's an example:    // blueColor = map(blueFrequency, 38, 84, 255, 0);   blueColor = map(blueFrequency, XX, XX, 255, 0);      // Printing the BLUE (B) value    Serial.print(" B = ");   Serial.print(blueColor);   delay(100);    // Checks the current detected color and prints   // a message in the serial monitor   if(redColor > greenColor && redColor > blueColor){       Serial.println(" - RED detected!");   }   if(greenColor > redColor && greenColor > blueColor){     Serial.println(" - GREEN detected!");   }   if(blueColor > redColor && blueColor > greenColor){     Serial.println(" - BLUE detected!");   } }

View raw code

To distinguish between different colors we have three conditions:

When the R is the maximum value (in RGB parameters) we know we have a red object
When G is the maximum value, we know we have a green object
When B is the maximum value, we know we have a blue object

Now, place something in front of the sensor. It should print in your serial monitor the color detected: red, green or blue.

Tip: your sensor can also detect other colors with more if statements.

Wrapping up

In this post you've learned how to detect colors with the TCSP3200 color sensor.

You can easily build a color sorting machine by simply adding a servo motor.

Do you have project ideas related to color sorting?

Let us know by posting a comment below.

If you like this post, you'll probably like these posts:

21 Arduino Modules You Can Buy For Less Than $2
Guide for Real Time Clock (RTC) Module with Arduino (DS1307 and DS3231)
Guide for 0.96 inch OLED Display with Arduino
20 Free Guides for Arduino Modules and Sensors
Guide for DHT11/DHT22 Humidity and Temperature Sensor With Arduino

Thanks for reading,

Rui and Sara

Using a Color Sensor to Draw Picture

Source: https://randomnerdtutorials.com/arduino-color-sensor-tcs230-tcs3200/