Arduino UNO TCRT5000: Read Line Sensor Values

Project Overview

Arduino UNO + TCRT5000 IR Line Tracking Sensor: In this tutorial, you will connect a TCRT5000 infrared reflective sensor module to an Arduino UNO and read analog values on the serial monitor to detect light vs. dark surfaces and close-range proximity.

Time: 15 to 30 minutes
Skill level: Beginner
What you will build: An Arduino-based setup that reads analog values from the TCRT5000 sensor and displays them on the serial monitor, allowing you to detect surface color and proximity.

TCRT5000 infrared reflective line tracking sensor module shown close up with IR emitter, receiver, and onboard potentiometer — The TCRT5000 infrared reflective sensor module used for line tracking and surface detection.

Parts List

From ShillehTek

TCRT5000 IR Reflective Line Follower Sensor for Arduino Robots - the infrared reflective sensor module with digital and analog outputs
120pcs Dupont Jumper Wires - for connecting the sensor to the Arduino

External

Arduino UNO R4
USB cable - to connect the Arduino to your computer for programming and serial monitoring
Computer with Arduino IDE installed

Note: The TCRT5000 module operates at 5V and provides both a digital output (DOUT) with an adjustable threshold via the onboard potentiometer and an analog output (AOUT) for continuous readings. The effective sensing distance is approximately 1 mm to 8 mm, with the optimal point around 2.5 mm.

Step-by-Step Guide

Step 1 - Understand the TCRT5000 sensor module

Goal: Learn how the TCRT5000 works and identify its pins.

What to do: The TCRT5000 module contains an infrared LED emitter and an infrared phototransistor receiver. It works by emitting an IR beam and measuring the amount of light reflected back. Dark surfaces absorb more IR light and reflect less, while light surfaces reflect more. This difference in reflected light produces varying voltage levels on the output pins.

The module has four pins:

VCC - power supply input (5V)
GND - ground connection
DOUT - digital output that goes HIGH or LOW based on the potentiometer threshold setting
AOUT - analog output that provides a continuous voltage proportional to the reflected IR intensity

The onboard potentiometer lets you adjust the sensitivity threshold for the digital output. Turn it to calibrate at what reflectance level the DOUT pin switches between HIGH and LOW.

TCRT5000 sensor module pinout diagram labeling VCC, GND, DOUT digital output, and AOUT analog output — TCRT5000 module pinout - VCC, GND, DOUT (digital), and AOUT (analog).

Expected result: You understand the sensor's operating principle and can identify all four pins on the module.

Step 2 - Gather the required materials

Goal: Collect everything you need for this project.

What to do: You will need an Arduino UNO, a TCRT5000 infrared reflective sensor module, and a few male-to-female jumper wires. Make sure you also have a USB cable to connect the Arduino to your computer and the Arduino IDE installed for uploading code and viewing serial output.

Arduino UNO with TCRT5000 IR sensor module and jumper wires laid out as required materials — Everything you need: Arduino UNO, TCRT5000 module, and jumper wires.

Expected result: All components are ready on your workbench.

Step 3 - Wire the TCRT5000 to the Arduino

Goal: Connect the sensor module to your Arduino UNO.

What to do: Use jumper wires to make the following connections between the TCRT5000 module and the Arduino:

VCC on the sensor to 5V on the Arduino
GND on the sensor to GND on the Arduino
AOUT on the sensor to A0 (analog pin 0) on the Arduino

For this tutorial, you will use the analog output to get continuous readings. If you want to use the digital output instead, connect DOUT to any digital pin on the Arduino and use digitalRead() in your code.

Wiring diagram of Arduino UNO connected to TCRT5000 sensor with VCC to 5V, GND to GND, and AOUT to A0 — Connect VCC to 5V, GND to GND, and AOUT to analog pin A0 on the Arduino.

Expected result: The TCRT5000 is wired to the Arduino and ready for programming.

Step 4 - Upload the Arduino sketch

Goal: Program the Arduino to read analog values from the TCRT5000 sensor and display them on the serial monitor.

What to do: Open the Arduino IDE, create a new sketch, and paste the following code. This program reads the analog voltage from pin A0 every 100 milliseconds and prints the value to the serial monitor.

Code:

// TCRT5000 IR Sensor Analog Read
// Reads reflected IR intensity from the TCRT5000 module

void setup() {
  // Start serial communication at 9600 baud
  Serial.begin(9600);
}

void loop() {
  // Read the analog value from pin A0
  int sensorValue = analogRead(A0);

  // Print the sensor reading to the serial monitor
  Serial.println(sensorValue);

  // Short delay between readings
  delay(100);
}

The analogRead(A0) function returns a value between 0 and 1023. Lower values indicate more reflected light (lighter surfaces closer to the sensor), while higher values indicate less reflected light (darker surfaces or greater distance). Upload the sketch to your Arduino using the Upload button.

Expected result: The sketch compiles and uploads to the Arduino without errors.

Step 5 - Test the sensor in the serial monitor

Goal: Observe the sensor readings in the serial monitor and verify detection of different surfaces.

What to do: Open the serial monitor in the Arduino IDE (Tools > Serial Monitor or Ctrl+Shift+M) and set the baud rate to 9600. You should see a stream of numbers updating every 100 milliseconds. Move a white surface in front of the sensor and note the values, then try a black surface. The readings should change noticeably between light and dark surfaces.

You can also adjust the distance between the sensor and the surface. The optimal detection range is around 2.5 mm from the sensor face. If you want to use the digital output, turn the onboard potentiometer to set the threshold where DOUT switches between HIGH and LOW.

Arduino IDE serial monitor showing changing analog readings from a TCRT5000 sensor as surfaces move in front of it — Serial monitor output showing analog readings from the TCRT5000 sensor.

Expected result: The serial monitor displays varying values that correspond to the reflectance of the surface in front of the sensor. White or light surfaces produce lower values and dark surfaces produce higher values.

Conclusion

You connected a TCRT5000 infrared reflective sensor to an Arduino UNO and read analog values that change based on surface color and distance. This is a practical building block for line-following robots, edge-detection systems, and simple proximity sensing applications. Using the analog output gives you continuous readings, and the digital output plus the onboard potentiometer provides a simple on/off threshold trigger.

Want the exact parts used in this build? Grab them from ShillehTek.com. If you want help customizing this project or building something for your product, check out our IoT consulting services.