TCS34725 on OLED: RGB Color Sensor
Overview & Wiring
What it is: The TCS34725 reads the colour of a surface as red, green, blue and clear (brightness) values, with an onboard white LED to illuminate the target. Great for colour-sorting robots and mood lamps.
How it works: I2C device at address 0x29. It returns 16-bit raw R/G/B/C counts; this sketch scales them to the familiar 0–255 range using the clear channel. Shares SDA/SCL with the OLED.
Wiring (shared I2C bus with the OLED):
TCS34725 SDA -> GPIO4
TCS34725 SCL -> GPIO5
TCS34725 VIN -> 3V3
TCS34725 GND -> GND
(optional) LED pin -> GND to force the white LED off, or leave open for on
OLED VCC=3V3, GND=GND, SDA=GPIO4, SCL=GPIO5
Libraries: "Adafruit TCS34725" (installs "Adafruit BusIO"), plus "Adafruit SSD1306" and "Adafruit GFX Library".
On screen / Serial: R, G and B values 0–255. Hold coloured paper about 1 cm away and watch the channels change.
Gotchas: Hold the target close and steady; ambient light throws readings off, which is why the onboard LED helps. Address 0x29 is fixed.
Circuit Diagram
Parts You Need
Source Code (Arduino / ESP32)
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include <Adafruit_TCS34725.h>
Adafruit_SSD1306 display(128, 64, &Wire, -1);
Adafruit_TCS34725 tcs = Adafruit_TCS34725(TCS34725_INTEGRATIONTIME_154MS, TCS34725_GAIN_4X);
void setup() {
Serial.begin(115200);
Wire.begin(4, 5);
display.begin(SSD1306_SWITCHCAPVCC, 0x3C);
if (!tcs.begin()) {
Serial.println("TCS34725 not found");
display.setTextColor(SSD1306_WHITE);
display.setCursor(0, 28); display.println("TCS34725 not found");
display.display();
while (1) delay(10);
}
}
void loop() {
uint16_t r, g, b, c;
tcs.getRawData(&r, &g, &b, &c);
int R = c ? (int)r * 255 / c : 0; // scale by clear channel
int G = c ? (int)g * 255 / c : 0;
int B = c ? (int)b * 255 / c : 0;
display.clearDisplay();
display.setTextColor(SSD1306_WHITE);
display.setTextSize(1);
display.setCursor(0, 0); display.println("TCS34725 Color");
display.setTextSize(2);
display.setCursor(0, 16); display.printf("R %d", R);
display.setCursor(0, 34); display.printf("G %d", G);
display.setCursor(0, 52); display.setTextSize(1); display.printf("B %d", B);
display.display();
Serial.printf("R %d G %d B %d\n", R, G, B);
delay(500);
}