About: Tecnical Teacher

Don't you have a car to ride? Do not worry. maybe you will not be able to ride but you will have a car you can use :)

If you want to enjoy the pleasure of using yourself or leave it...

And no more words. Ladies and Gentlemen Please Welcome “4WD SMART ROBOT CAR”

Step 1: Quick Info

Hi Makers,

We have good news for you. In this tutorial, we are now a classic model. 4WD SMART ROBOT CAR. If you have this car, you will be able to avoid obstacles and follow the necessary lines to reach your destination and protect the distances. You can do this autonomously. If you want to have control with your hands, you will be able to control your car with APK via the Bluetooth module.

Step 2: Features of the 4WD SMART ROBOT CAR?

You know, or you've seen, car kits usually have a plastic chassis. We have designed as PCB. This will save you from the unnecessary cable crowds. You'll also have a more elegant and simple look.

4WD SMART ROBOT CAR is exactly a "plug and play" kit. You won't need cable connections too much. Because of the PCB we designed, we made the necessary paths for you.

What are the main features of the 4WD SMART ROBOT CAR?

- Bluetooth Control

- Obstacle Avoiding

- Line tracking or following

- Ultrasonic distance

Step 3: Equipments and Materials

We talk about before we need a PCB for car. So you have to 25*15 cm dimention PCB. And next;

- Arduino UNO & USB Cable

- L298N Motor Driver

- HC05 Bluetooth Module

- HSR04 Ultrasonic Distance Sensor

- TCRT5000 Line Tracking Sensor

- IR Infrared Obstacle Avoidance Sensor

- 6V DC Gear Motor and Wheel

- LEDs

- Header Pins

- Jumpers

- LiPo Rechargeable Battery

Step 4: Built a Car Chassis

We are using Proteus with ISIS for PCB drawing. As you can see in pic, we put a sample . And than ve cut it with CNC Lazer engraver.

Step 5: Start to Kit

We designed non cable a PCB. So, we are using header pins for sensor and modules. As you see in pics, we put many header pin.

Step 6: Lamps - Signalling - On-Off

You can see below timestamp details.

Step 7: Motor and Wheel Assembly

as you can see, we used a 3d Printed part as motor holder. And of course we designed it again :D You can find 3d printer files on last steps.

Step 8: Sensors and Modules Assembly

We explained that we are using some sensors and modules.

Features are line , avoiding , distance and bluetooth.

So What is line tracking or follower ?

The Line Tracking Sensor is most useful for detecting a contrast between dark and light objects. This makes it particularly well suited for tracking dark lines on light surfaces. For best results when using the Line Tracking

Sensors, it is best to mount the sensors between 1/8 and 1/4 of an inch away from the surface it is measuring. It is also important to keep lighting in the room consistent, so sensors’ readings remain accurate.

Code Sample :

if(digitalRead(11)==1 && digitalRead(12)==0)
{ right(); //



if(digitalRead(11)==0&& digitalRead(12)==1)

{ left(); //



if(digitalRead(11)==1 && digitalRead(12)==1)

{ forward(); //



if(digitalRead(11)==0 && digitalRead(12)==0)

{ timer++; if (timer<100)

{ left(); // digitalWrite(4,LOW); timer=0;


Step 9:

What is Obstacle Avoidance Sensor ?

This Infrared Obstacle Avoidance Sensor returns a signal when it detects an object in range. The range of the sensor is around 2-40 cm is distance. It operates at 3.5 to 5 volts at around 20 milliamps. The Obstacle Avoidance Sensors usually come in two types - with 3 and 4 pins. The 3 pin version does not have the ability to be enabled/disabled. The 4 pin version has optional Enable pin. Infrared obstacle avoidance sensor is designed to detect obstacles or the difference in reflective services. One application is to help a wheeled robot avoid obstacles with a sensor to react to adjustable distance settings. This device has an infrared transmitter and receiver, that forms the sensor pair. The transmitter LED emits a certain frequency of infrared, which the receiver LED will detect. The receiving LED will detect some of the signal back and will trigger the digital on/off “signal” pin when a specific threshold “distance” has been detected. Most boards will have 2 potentiometers, one of which is to adjust how sensitive the sensor is. You can use it to adjust the distance from the object at which the sensor detects it. Typically, the other potentiometer, which changes the transmitter IR frequency is not adjusted.

Code Sample:

float getDistance(int trig,int echo)







pinMode(echo, INPUT);

return pulseIn(echo,HIGH,30000)/58.0;


Step 10:

What is Bluetooth Module ?

HC-05 Bluetooth Module is an easy to use Bluetooth SPP (Serial Port Protocol) module, designed for transparent wireless serial connection setup. Its communication is via serial communication which makes an easy way to interface with controller or PC. HC-05 Bluetooth module provides switching mode between master and slave mode which means it able to use neither receiving nor transmitting data.

VCC  Arduino 5V

GND  Arduino GND

TXD  Arduino Pin RX

RXD  Arduino Pin TX

Step 11:

What is Motor Driver ?

The L298N Motor Driver Module is a high voltage Dual H-Bridge manufactured by ST company. It is designed to accept standard TTL voltage levels. H-bridge drivers are used to drive inductive loads that requires forward and reverse function with speed control such as DC Motors, and Stepper Motors. This Dual H-Bridge driver is capable of driving voltages up to 46V and continuous current up to 2A in each channels.

1-DC motor 1 "+" or stepper motor A+

2-DC motor 1 "-" or stepper motor A-

3-12V jumper - remove this if using a supply voltage greater than 12V DC. This enables power to the onboard 5V regulator

4-Connect your motor supply voltage here, maximum of 35V DC. Remove 12V jumper if >12V DCGND5V output if 12V jumper in place, ideal for powering your Arduino (etc)

5-DC motor 1 enable jumper. Leave this in place when using a stepper motor.

6-Connect to PWM output for DC motor speed control.





11-DC motor 2 enable jumper. Leave this in place when using a stepper motor.

12-Connect to PWM output for DC motor speed control.

13-DC motor 2 "+" or stepper motor B+

14-DC motor 2 "-" or stepper motor B

Step 12:

What is Ultrasonic Distance Sensor?

An ultrasonic sensor is an instrument that measures the distance to an object using ultrasonic sound waves.
An ultrasonic sensor uses a transducer to send and receive ultrasonic pulses that relay back information about an object’s proximity. High-frequency sound waves reflect from boundaries to produce distinct echo patterns.

Ultrasonic sound vibrates at a frequency above the range of human hearing.
Transducers are the microphones used to receive and send the ultrasonic sound.

Step 13: Arduino and Wheel Assembly

We are going to last steps. And now in arduino step. We designed some pins for " plug ". Thus , Easy to install and remove arduino. And we put it undet the PCB as you see in pic.

And we assemble all wheels and now we have a car :D

Step 14: Sample Pictures

Step 15: Showcases

Step 16: Files

We share files below. Include, arduino codes and 3d Printer files.

Thanks For Patience

Good Luck....

Arduino Contest 2019

This is an entry in the
Arduino Contest 2019



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