Help With TCS3200 (Understanding Output)
aerouta
Posts: 7
Hello, I am using a version of the code posted in the forum below to read colors then ultimately match them. However, I am not sure what the output (white, red, green, blue) are. I would expect that the RGB values be between 0 and 255, but that is not the case. I have reviewed alot of information on the Parallax and TAOS site. My guess it has something to do with the Spectral Response charts included in the sensor documentation however the y-axis (Relative Response) is never clearly defined, this renders their meaning elusive. I am sure Im missing something quite elementary but I cant seem to put it all together. Any help would be great.
/*
Eecher's TCS3200 program
adapted from code found at reibot.org
*/
int S0 = 8;//pinB
int S1 = 9;//pinA
int S2 = 12;//pinE
int S3 = 11;//pinF
int taosOutPin = 10;//pinC
int LED = 13;//pinD
void setup() {
TCS3200setup();
Serial.begin(115200);
Serial.print("\n\n\nready\n\n\n");
delay(100);
}
// primary loop takes color readings from all four channels and displays the raw values once per second. What you might wish to do with those values is up to you...
void loop() {
detectColor(taosOutPin);
Serial.print("\n\n\n");
delay(1000);
}
int detectColor(int taosOutPin){
float white = colorRead(taosOutPin,0,1);
float red = colorRead(taosOutPin,1,1);
float blue = colorRead(taosOutPin,2,1);
float green = colorRead(taosOutPin,3,1);
Serial.print("white ");
Serial.println(white);
Serial.print("red ");
Serial.println(red);
Serial.print("blue ");
Serial.println(blue);
Serial.print("green ");
Serial.println(green);
}
/*
This section will return the pulseIn reading of the selected color.
It will turn on the sensor at the start taosMode(1), and it will power off the sensor at the end taosMode(0)
color codes: 0=white, 1=red, 2=blue, 3=green
if LEDstate is 0, LED will be off. 1 and the LED will be on.
taosOutPin is the ouput pin of the TCS3200.
*/
float colorRead(int taosOutPin, int color, boolean LEDstate){
//turn on sensor and use highest frequency/sensitivity setting
taosMode(1);
//setting for a delay to let the sensor sit for a moment before taking a reading.
int sensorDelay = 100;
//set the S2 and S3 pins to select the color to be sensed
if(color == 0){//white
digitalWrite(S3, LOW); //S3
digitalWrite(S2, HIGH); //S2
// Serial.print(" w");
}
else if(color == 1){//red
digitalWrite(S3, LOW); //S3
digitalWrite(S2, LOW); //S2
// Serial.print(" r");
}
else if(color == 2){//blue
digitalWrite(S3, HIGH); //S3
digitalWrite(S2, LOW); //S2
// Serial.print(" b");
}
else if(color == 3){//green
digitalWrite(S3, HIGH); //S3
digitalWrite(S2, HIGH); //S2
// Serial.print(" g");
}
// create a var where the pulse reading from sensor will go
float readPulse;
// turn LEDs on or off, as directed by the LEDstate var
if(LEDstate == 0){
digitalWrite(LED, LOW);
}
if(LEDstate == 1){
digitalWrite(LED, HIGH);
}
// wait a bit for LEDs to actually turn on, as directed by sensorDelay var
delay(sensorDelay);
// now take a measurement from the sensor, timing a low pulse on the sensor's "out" pin
readPulse = pulseIn(taosOutPin, LOW, 80000);
//if the pulseIn times out, it returns 0 and that throws off numbers. just cap it at 80k if it happens
if(readPulse < .1){
readPulse = 80000;
}
//turn off color sensor and LEDs to save power
taosMode(0);
// return the pulse value back to whatever called for it...
return readPulse;
}
// Operation modes area, controlled by hi/lo settings on S0 and S1 pins.
//setting mode to zero will put taos into low power mode. taosMode(0);
void taosMode(int mode){
if(mode == 0){
//power OFF mode- LED off and both channels "low"
digitalWrite(LED, LOW);
digitalWrite(S0, LOW); //S0
digitalWrite(S1, LOW); //S1
// Serial.println("mOFFm");
}else if(mode == 1){
//this will put in 1:1, highest sensitivity
digitalWrite(S0, HIGH); //S0
digitalWrite(S1, HIGH); //S1
// Serial.println("m1:1m");
}else if(mode == 2){
//this will put in 1:5
digitalWrite(S0, HIGH); //S0
digitalWrite(S1, LOW); //S1
//Serial.println("m1:5m");
}else if(mode == 3){
//this will put in 1:50
digitalWrite(S0, LOW); //S0
digitalWrite(S1, HIGH); //S1
//Serial.println("m1:50m");
}
return;
}
void TCS3200setup(){
//initialize pins
pinMode(LED,OUTPUT); //LED pinD
//color mode selection
pinMode(S2,OUTPUT); //S2 pinE
pinMode(S3,OUTPUT); //s3 pinF
//color response pin (only actual input from taos)
pinMode(taosOutPin, INPUT); //taosOutPin pinC
//communication freq (sensitivity) selection
pinMode(S0,OUTPUT); //S0 pinB
pinMode(S1,OUTPUT); //S1 pinA
return;
}
Comments
byte s0=8,s1=9,s2=12,s3=11, LED = 13;int out=2; int flag=0; byte counter=0; byte countR=0,countG=0,countB=0; void setup() { Serial.begin(115200); pinMode(s0,OUTPUT); pinMode(s1,OUTPUT); pinMode(s2,OUTPUT); pinMode(s3,OUTPUT); pinMode(LED,OUTPUT); } void TCS() { flag=0; digitalWrite(s1,HIGH); digitalWrite(s0,HIGH); digitalWrite(s2,LOW); digitalWrite(s3,LOW); digitalWrite(LED,HIGH); attachInterrupt(0, ISR_INTO, LOW); timer0_init(); } void ISR_INTO() { counter++; } void timer0_init(void) { TCCR2A=0x00; TCCR2B=0x07; //the clock frequency source 1024 points TCNT2= 100; //10 ms overflow again TIMSK2 = 0x01; //allow interrupt } int i=0; ISR(TIMER2_OVF_vect)//the timer 2, 10ms interrupt overflow again. Internal overflow interrupt executive function { TCNT2=100; flag++; if(flag==1) { countR=counter; //Serial.print("red=");Serial.println(countR,DEC); digitalWrite(s2,HIGH); digitalWrite(s3,HIGH); } else if(flag==2) { countG=counter; //Serial.print("green="); Serial.println(countG,DEC); digitalWrite(s2,LOW); digitalWrite(s3,HIGH); } else if(flag==3) { countB=counter; //Serial.print("blue="); Serial.println(countB,DEC); Serial.println("\n"); digitalWrite(s2,LOW); digitalWrite(s3,LOW); } else if(flag==4) { flag=0; //Serial.print("white "); Serial.println("0"); Serial.print("red "); Serial.println(countR,DEC); Serial.print("blue "); Serial.println(countB,DEC); Serial.print("green "); Serial.println(countG,DEC); Serial.print("\n\n\n"); Serial.print("0");Serial.print(" ");Serial.print(countR,DEC);Serial.print(" ");Serial.print(countG,DEC);Serial.print(" ");Serial.println(countB,DEC); } counter=0; } void loop() { TCS(); while(1); }BTW, you can safely ignore the clear channel from the sensor.
-Phil
I looked through the PDF provided on the parallax site for information on white balancing, I was not able to find it. But you response was intiutive enough.
Do you recommend using the first or second approach for reading the sensor output. The first code; a pure white subject approaches an RGB reading of [0 0 0] and a black subject [INF INF INF]. While the second approach seems to do the inverse.
Also, I am taking a reading of a transparent colored fuild in a circular test tube. Do you recommend using a square tube instead to avoid the glare? Or I could not use the sensor mounted LEDs and reposition some to the sides? I think this may help ensure that I am not reading the specular reflection. I would like to match the tube reading to a color card.
Gbalanced = Graw * 255 / Gwhite
Bbalanced = Braw * 255 / Bwhite
If you're using a BASIC Stamp, be sure to take the necessary steps to account for 16-bit overflow.
-Phil
-Phil
I have reviewed several white LED output spectrums. Most of them seem to have a dip in the 480-500nm range. Why is this? Does this not mean that I will loss sensitivity in that range because there will be very minimal light being reflected with that wavelength? I was comparing the two spectral response graphs for the TCS3200DB. The spectral response dips significantly at ~490 with the white LED Illumination.