Documentation

// GY-31 TCS3200 - Read raw red, green, blue frequencies on Arduino
// S0/S1 set frequency scaling. S2/S3 select which color filter is active.
// Lower frequency on a color = more of that color reflected.

const int S0  = 4;
const int S1  = 5;
const int S2  = 6;
const int S3  = 7;
const int OUT = 8;

void setup() {
  Serial.begin(9600);
  pinMode(S0, OUTPUT); pinMode(S1, OUTPUT);
  pinMode(S2, OUTPUT); pinMode(S3, OUTPUT);
  pinMode(OUT, INPUT);

  // Set frequency scaling to 20% (S0=H, S1=L)
  digitalWrite(S0, HIGH);
  digitalWrite(S1, LOW);
}

unsigned long readColor(int s2, int s3) {
  digitalWrite(S2, s2);
  digitalWrite(S3, s3);
  delay(50);
  return pulseIn(OUT, LOW);  // microseconds per low half-cycle
}

void loop() {
  unsigned long red   = readColor(LOW,  LOW);
  unsigned long blue  = readColor(LOW,  HIGH);
  unsigned long green = readColor(HIGH, HIGH);

  Serial.print("R="); Serial.print(red);
  Serial.print("  G="); Serial.print(green);
  Serial.print("  B="); Serial.println(blue);

  delay(300);
}

// ESP32 + TCS3200: read R/G/B and guess a color name
// Calibrate MIN/MAX values by holding white and black under the sensor and
// noting the printed values, then update the constants below.

const int S0 = 18, S1 = 19, S2 = 21, S3 = 22, OUT = 23;

// Calibration -- replace with your own readings
const int R_MIN = 30, R_MAX = 250;
const int G_MIN = 35, G_MAX = 270;
const int B_MIN = 30, B_MAX = 240;

void setup() {
  Serial.begin(115200);
  pinMode(S0, OUTPUT); pinMode(S1, OUTPUT);
  pinMode(S2, OUTPUT); pinMode(S3, OUTPUT);
  pinMode(OUT, INPUT);
  digitalWrite(S0, HIGH); digitalWrite(S1, LOW);  // 20% scaling
}

int read(int s2, int s3) {
  digitalWrite(S2, s2); digitalWrite(S3, s3);
  delay(50);
  return pulseIn(OUT, LOW);
}

int normalize(int v, int lo, int hi) {
  int n = map(v, lo, hi, 255, 0);
  return constrain(n, 0, 255);
}

void loop() {
  int r = normalize(read(LOW,  LOW),  R_MIN, R_MAX);
  int g = normalize(read(HIGH, HIGH), G_MIN, G_MAX);
  int b = normalize(read(LOW,  HIGH), B_MIN, B_MAX);

  String name = "?";
  if (r > 180 && g < 100 && b < 100) name = "RED";
  else if (g > 150 && r < 120 && b < 120) name = "GREEN";
  else if (b > 150 && r < 120 && g < 150) name = "BLUE";
  else if (r > 200 && g > 200 && b > 200) name = "WHITE";
  else if (r < 60 && g < 60 && b < 60)    name = "BLACK";

  Serial.printf("R=%3d  G=%3d  B=%3d  -> %s\n", r, g, b, name.c_str());
  delay(400);
}

# GY-31 TCS3200 on Raspberry Pi Pico (MicroPython)
# Wiring: S0=GP10 S1=GP11 S2=GP12 S3=GP13 OUT=GP14

from machine import Pin, time_pulse_us
import time

S0 = Pin(10, Pin.OUT); S1 = Pin(11, Pin.OUT)
S2 = Pin(12, Pin.OUT); S3 = Pin(13, Pin.OUT)
OUT = Pin(14, Pin.IN)

# 20% frequency scaling
S0.value(1); S1.value(0)

def read(s2, s3):
    S2.value(s2); S3.value(s3)
    time.sleep_ms(50)
    return time_pulse_us(OUT, 0, 30000)  # microseconds per low half-cycle

while True:
    r = read(0, 0)
    b = read(0, 1)
    g = read(1, 1)
    print("R={:4d}  G={:4d}  B={:4d}".format(r, g, b))
    time.sleep(0.3)