I’ve spent a day playing with the TCS3200 color sensor from TAOS (now ams AG). I’ve connected it to an Arduino and sent the color over the serial port to an application written in Processing. The application outputs the color found by drawing a square.
The hardware
The datasheet for the TCS3200 is found here.
The Arduino Application
The Arduino application sets up the color sensor and retrieves the detected color every ~250ms. The color is sent through the serial port (USB) to the processing application.
The code
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// // Pin configuration // - Change these // #define PIN_OE 3 #define PIN_OUT 2 #define PIN_S0 5 #define PIN_S1 4 #define PIN_S2 6 #define PIN_S3 7 // // Frequency scaling // #define FREQSCALE_POWERDOWN 0 #define FREQSCALE_2 1 #define FREQSCALE_20 2 #define FREQSCALE_100 3 int freqScaleTable[4][2] = {{LOW,LOW},{HIGH,LOW},{LOW,HIGH},{HIGH,HIGH}}; // Set frequency scaling void tcs3200_setFreqScale(int freqScale) { digitalWrite(PIN_S0, freqScaleTable[freqScale][1]); digitalWrite(PIN_S1, freqScaleTable[freqScale][0]); } // // Color set-up // #define COLOR_RED 0 #define COLOR_BLUE 1 #define COLOR_CLEAR 2 #define COLOR_GREEN 3 int colorTable[4][2] = {{LOW,LOW},{HIGH,LOW},{LOW,HIGH},{HIGH,HIGH}}; // Set color void tcs3200_setColor(int color) { digitalWrite(PIN_S2, colorTable[color][1]); digitalWrite(PIN_S3, colorTable[color][0]); } // // Color functions // void tcs3200_init() { // Pin modes pinMode(PIN_OE, OUTPUT); pinMode(PIN_OUT, INPUT); pinMode(PIN_S0, OUTPUT); pinMode(PIN_S1, OUTPUT); pinMode(PIN_S2, OUTPUT); pinMode(PIN_S3, OUTPUT); // Enable f0 digitalWrite(PIN_OE, LOW); // Set frequency scaling to 2 // Gives better accuracy with the slow arduino tcs3200_setFreqScale(FREQSCALE_2); } unsigned long tcs3200_getRed() { tcs3200_setColor(COLOR_RED); delay(10); return pulseIn(PIN_OUT, HIGH); } unsigned long tcs3200_getGreen() { tcs3200_setColor(COLOR_GREEN); delay(10); return pulseIn(PIN_OUT, HIGH); } unsigned long tcs3200_getBlue() { tcs3200_setColor(COLOR_BLUE); delay(10); return pulseIn(PIN_OUT, HIGH); } unsigned long tcs3200_getAll() { tcs3200_setColor(COLOR_CLEAR); delay(10); return pulseIn(PIN_OUT, HIGH); } // // setup and loop // unsigned long red=0, green=0, blue=0, all=0; void setup() { tcs3200_init(); Serial.begin(9600); } void loop() { // Get colors red = 85000/tcs3200_getRed(); green = 100000/tcs3200_getGreen(); blue = 100000/tcs3200_getBlue(); // Sum all colors all = red + green + blue; // Output to serial Serial.write((unsigned char)0xff); // Preamble Serial.write((unsigned char)0xaa); // Preamble Serial.write((unsigned char)red); Serial.write((unsigned char)green); Serial.write((unsigned char)blue); // Wait before next cycle delay(200); } |
How to set up
Connect the color sensor to the Arduino following the pin configurations, or change the pin configuration to match your hardware set up (lines 5-10). All pins should be at digital pins, except Vcc and ground. I’ve powered my device from the Arduino USB power, and it worked nicely.
How it works
The color sensor is set up with a 2% frequency scaling, which means that the frequency range of the output pin is between 250Hz and 400Hz, where low frequencies are dark and high frequencies are bright. The frequency scaling type is chosen by toggeling the S1 and S2 pins. Each color is read separately, and which color to read is chosen by toggling the S2 and S3 pins. The frequency of each color is read by the pulseIn call, which gives the period of the pulse. The values are calculated to match the values used to print colors on a computer screen, and sent by the serial port to the Processing application.
The Processing Application
This application receives the color value from the serial port and draws a rectangle from it.
The code
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import processing.serial.*; // Preambles to search for in serial data // This is to keep the red, green and blue in sync int PREAMBLE_A = 0xff; int PREAMBLE_B = 0xaa; // Working variables and objects Serial arduinoPort; int red=0, green=0, blue=0; void setup() { // Set up main window size(200, 200); background(0); // Set up serial connection arduinoPort = new Serial(this, "COM7", 9600); } void draw() { // Wait for a packet of >= 5 bytes if (arduinoPort.available() >= 5) { if (arduinoPort.read() == PREAMBLE_A) { if (arduinoPort.read() == PREAMBLE_B) { // Got both preamble bytes, read colors red = arduinoPort.read(); green = arduinoPort.read(); blue = arduinoPort.read(); // Output color to console print("Got color: " + red + "," + green + "," + blue + "\n"); } } } // Output color to main window background(255); fill(red, green, blue); rect(50, 50, 100, 100); } |
How to set up
Choose the correct COM port name for your Arduino. Mine was at “COM7”. This is set up in line 19.
How it works
The loop polls the serial line continuously for the pattern FFAA in hex. When this is found, the following three bytes will be the red, green and blue values. These bytes are read and used to color the rectangle.
2 comments
Jack Nguyen
December 16, 2016 at 10:36 (UTC 1) Link to this comment
” red = 85000/tcs3200_getRed();
green = 100000/tcs3200_getGreen();
blue = 100000/tcs3200_getBlue(); ”
could you please explain, why 85000 and 100000?
Thanks
larsivar
December 20, 2016 at 10:41 (UTC 1) Link to this comment
Hi!
I tweaked it so that the color I measured looked more accurate at the screen. It may be that the light in my workshop is more yellow than it looks, so it works like a white balance adjustment. I didn’t spend a whole lot of time on it, so it might be wrong. Go right ahead and tweak, you might get better results using 100000, or any other value 🙂