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In this lesson, we will add 5 black/white tracking sensors to the framework built in Lesson 1. If you have not completed installation in Lesson 1, please review Lesson 1

The software in this lesson will read data from these 5 black/white tracking sensors and automatically guide the smart car to move along the black track line in the white ground.

Parts and Devices:

Hardware Installation:
Step 1: Motor driver(Model-X )pin installation.
Start the installation from previous status of Smart Car Lesson 1 . If you have installed Lesson 2 or 3 no need change anything, just keep the hardware wire connection as is.

Step 2:  Remove screws on copper pillars and install 5pcs tracking sensor modules at the front of lower car chassis with 5pcs M2.5 plasctic screws, M2.5 plastic pillars and M2.5 plastic nuts. Make sure that every sensor head is over the gaps at the front side of lower car chassis so that the sensor can detect black lines in white ground.

Step 3: From left to right, connect the D0(D zero) pin in tracking sensor module to A0, A1, A2, A3, A4 pin in UNO board. Use 1pin male to 5 pins female jumper wires to connect VCC and GND of 5pcs tracking sensor modules. Connect VCC of tracking sensor module to 5V in UNO board, GND to GND. As the following photo shows (Remember : DO NOT remove any existing wires installed in Lesson 1 ):

Step 4: Fix the screws on copper pillars to connect upper chassis to lower chassis.

Software Installation:

Open-source Arduino
Download Arduino IDE here:
7 zip is a free zip
utility that un-zips zip files
Download 7zip here for free

Step 1: Install latest Arduino IDE (If you have Arduino IDE version after 1.1.16, please skip this step). Download Arduino IDE from , then install the software.

Step 2: Download Lesson 4 tracking smart car sample code from , unzip the download zip file, you will see a folder called smartcar-lesson4 .

Step 3: Connect UNO R3 board to PC with USB cable, Open Arduino IDE -> click file -> click Open -> choose code “smartcar-lesson4.ino” in smartcar-lesson4 folder, load the code into arduino. (Notice: Shut off your battery or Unplug your power adapter when upload sketch code to Arduino.)

Step 4: Choose corresponding board/port for your project,upload the sketch to the board.

Step 5: Adjust the sensitivity of tracking sensor modules. Turn on and hold the car and adjust the potentiometer on the tracking sensor with cross screwdriver until you get the best sensitivity status: the signal indicate LED light will turn on when sensor is above white ground, and the signal LED will turn off when the sensor is above black track


Prepare a black track (the width of the black track is more than 20mm and less than 30mm) in white ground. Please note, the bend angle of track can’t be larger than 90 degree. If the angle is too large, the car will move out of the track.

Turn on the car and put the middle of tracking sensor module facing over black track, and then the car will move along the black track.