Line Finder Module:
The Line Finder Module applies the principle that infrared rays reflect differently on surfaces of different colors. After electrified, the infrared diode on the module sends out infrared rays constantly. When they encounter a white surface, the diffused reflection happens and the reflected rays are received by the receiver on the module. On the other hand, when they come across a black one, the receiver cannot get any infrared. Thus, the processor can tell whether it is a white or black detected surface by receiving the reflected infrared rays or not. Based on this, the module is usually used in line finding on a smart car.

As can be seen on the picture, the line finder module is divided into anode, cathode and a signal wire. The signal wire needs to be adjusted by a potentiometer when it is connected to a digital port.

1 * microbit
1 * microbit expansion board
1 * USB cable
1 * line finder module
1 * white paper stick with black tape.
- Several Jumper wires

Code：
Makecode：

MU Python:

  #-----------------------------------------------------------
# File name   : Line_finder.py.
# Description : Line_finder module
# Author      : jason
# E-mail      : jason@adeept.com
# Website     : www.adeept.com
# Date        : 2018/01/08
#-----------------------------------------------------------
from microbit import *
 
while True:
    # define Line_finder pin
    Line_finder = pin0.read_analog()
    if Line_finder < 500:
       display.show(Image.HAPPY)
    else:
        display.show(Image.SAD)

Click “flash” and download the code onto the micro:bit.
Now you can see the data read from the infrared line finder module on the serial port.
Effect Picture：

Components
- 1 * Adeept Arduino UNO R3 Board
- 1 * Line Finder Module
- 1 * USB Cable
- 1 * 3-Pin Wires

Build the circuit

Code:

  /***********************************************************
File name: _24_LineFinderModule.ino
Description: The information of line finder module has been
             detected by UNO R3,and displayed in the serial monitor 
Website: www.adeept.com
E-mail: support@adeept.com
Author: Tom
Date: 2017/03/15 
***********************************************************/
int linefinderPin=8;             //Set the digital 8 to the S pin
void setup() {
  pinMode( linefinderPin,INPUT); //initialize the line finder S pin as input
  Serial.begin(9600);           //opens serial port, sets data rate to 9600 bps
}
 
void loop() {
  if(digitalRead(linefinderPin)==LOW){
     Serial.println("White"); //send data to the serial monitor
  }else{
     Serial.println("Black"); //send data to the serial monitor
  }
  delay(200);                  //delay 0.2s
}

Compile and download the sketch to the UNO R3 board.

Open the Serial Monitor in Arduino IDE. Place the sensor module over a piece of white paper and another of black and you will see the data detected on the window. You can adjust the blue potentiometer on the module to change the sensitivity.

Components
- 1 * Raspberry Pi
- 1 * GPIO Extension Board
- 1 * 40-Pin GPIO Cable
- 1 * Breadboard
- 1 * Line Finder Module
- 1 * 3-Pin Wires

Build the circuit

Code: C code:

  #include <wiringPi.h>
#include <stdio.h>
 
#define TrackSensorPin_S  0
 
int main(void)
{
	if(wiringPiSetup() == -1){
		printf("setup wiringPi failed !\n");
		return -1; 
	}
 
	pinMode(TrackSensorPin_S, INPUT);
 
	while(1){
		if(digitalRead(TrackSensorPin_S) == LOW){
			printf("White line is detected\n");
			delay(100);
		}	
		else{
			printf("...Black line is detected\n");
			delay(100);
		}
	}
 
	return 0;
}

Python code:

  #!/usr/bin/env python
import RPi.GPIO as GPIO
 
TrackSensorPin_S = 11
 
def setup():
	GPIO.setmode(GPIO.BOARD)       # Numbers GPIOs by physical location
	GPIO.setup(TrackSensorPin_S, GPIO.IN, pull_up_down=GPIO.PUD_UP)    # Set Pin's mode is input, and pull up to high level(3.3V)
 
def loop():
	while True:
		if GPIO.input(TrackSensorPin_S) == GPIO.LOW:
			print '...White line is detected !'
		else:
			print 'Black line is detected...'
 
def destroy():
	GPIO.cleanup()             # Release resource
 
if __name__ == '__main__':     # Program start from here
	setup()
	try:
		loop()
	except KeyboardInterrupt:  # When 'Ctrl+C' is pressed, the child program destroy() will be  executed.
		destroy()

For C language users:

Step 2: Edit and save the code with vim or nano.

(code path: /home/Adeept_Sensor_Kit_for_RPi_C_Code/18_tracking/tracking.c)\\

Step 3: Compile$ sudo gcc tracking.c -o tracking -lwiringPi

Step 4: Run

$ sudo ./tracking

For Python users:

Step 2: Edit and save the code with vim or nano.

(code path: /home/Adeept_Sensor_Kit_for_RPi_Python_Code/18_ tracking.py)

Step 3: Run

$ sudo python 18_tracking.py

Place the sensor module over a piece of white paper and another of black and you will see the data detected on the terminal. You can adjust the blue potentiometer on the module to change the sensitivity.

Reference material：http://www.adeept.com/learn/
Video：http://www.adeept.com/video/