Octopus Electronic Bricks! You can use them build electronics projects just as easy as piling bricks! By using Octopus electronic bricks, you may connect Arduino or compatible boards easily with various digital, analog and I2C/Uart interfaces. These breadboard-less firm connections includes an extensive collection of modules like potentiometers, sensors, relays, servos, and even buttons. Just plug and play!
The Octopus 2-Channel Tracking Module has two integrated groups of reflective infrared pair diodes, which can be used to identify black lines. This module is usually used to make line tracking mini smart cars. You can design a black track and make your cars follow it through programming!
Connect this module to your micro:bit car.
Connect the left port to P13 and the right port to P14. (Based on the driver's angle of view)
You can see the whole program from the link here
Place the car on the black line, turn on the switch, then it will move forward along the black line.