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How does a line tracking robot work?

line tracing robot

Line tracking car

Working principle of line tracking car

Car tracking system based on 51 single chip microcomputer.

The system uses two groups of highly sensitive photocells to detect the black track of the road surface, and uses the single chip microcomputer to generate PWM wave to control the speed of the car. The test results show that the system can track the given path smoothly.


In the previous national student electronic design competitions, the simple intelligent car integrating light, machine and electricity has appeared many times. After demonstration, comparison and experiment, we have made the tracking circuit system of the simple car. The whole system is based on the mechanical structure of the ordinary toy car, and uses the car chassis, front and rear wheel motors and their automatic recovery device to track the black track of the road smoothly.

line tracing robot

line tracing robot


Overall scheme

The whole circuit system is divided into three modules: detection, control and drive. Firstly, the photoelectric tube is used to detect the road signal. After being processed by the comparator, it is sent to the software control module for real-time control, and the corresponding signal is output to the drive chip to drive the motor to rotate, so as to control the movement of the whole car


Sensing detection units

The smart car runs on the white paper “road” with black lines. Because the reflection coefficients of the black line and white paper are different, the “road” – black line can be judged according to the strength of the received reflected light. In this module, we can use a simple and widely used detection method – infrared detection method.

  • infrared detection method

infrared detection method, that is, using the characteristics of infrared with different reflection properties on physical surfaces of different colors. Infrared light is continuously emitted to the ground during the driving of the trolley. When the red light meets the white ground, diffuse emission occurs, and the reflected light is received by the receiving tube installed on the trolley; If the black line is encountered, the infrared light is absorbed, and the receiving tube on the trolley cannot receive the signal.

  • sensor selection

There are many devices used for infrared detection in the market. The self-made probe can be made by using the simple external circuit of the reflective sensor, or the integrated infrared probe with simple structure and reliable working performance can be used.

ST series integrated infrared probe is cheap, small, easy to use, reliable and widely used. Therefore, st168 reflection sensor is finally selected as the infrared light transmitting and receiving device in the system, and its internal structure and external circuit are relatively simple.

st168 detection circuit diagram

st168 detection circuit diagram


Applications in our daily life

  • Industrial Applications: These robots can be used as automated equipment carriers in industries replacing traditional conveyer belts.
  • Automobile applications: These robots can also be used as automatic cars running on roads with embedded magnets.
  • Domestic applications: It can also be used at homes like floor cleaning etc.
  • Guidance applications: It be used in public like shopping malls, bank, hotel etc to provide path guidance.


What’s accessories do i need for a line tracking robot?

Above are the accessories that for a line tracking robot. It’s a basic robot for starters.

What can line tracking robot kit used for?

1. It can be used in schools ,learning centers, educational institutions to cooperate with teachers’ STEM courses.

2. As home science educational toys that being an interactive toys between parents and children.

3. Making into an monthly activity boxes or subscription boxes for kids 

4. Science tools for kids

5. Robotics for schools

Where to buy the line tracking robot kit

You could get the line tracking robot kit on local Amazon shop and you may get it quickly.

If you are need sourcing line tracking robot wholesale. You could check this line tracking robot.



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