To design this car was started by an inspiration that why we don't make good use of the smart phone to control a smart car as we use mobile phone more and more time? The app of smart phone is dead because you can only see it on the screen but not in the real space. However, we find that we can easily use the usual thing in life to design something unusual.

This is a Bluetooth-controlled car. It operates by a smartphone app. This is an economical toy in this category. This can be operated from a decent distance than a regular remote controlled radio signal toy. This car is pretty powerful as it has 4 motors for all 4 wheels.

Smartphone-Controlled Mobile Hub

Creating a modular mobile robot that can be steered with high precision using a custom Bluetooth application.

• Action String Parsing: The Arduino receives single-character commands (e.g., 'F', 'L', 'S') via the HC-05 BT module. This controls the high-speed logic for the L298N motor driver.
• Differential Maneuvering Matrix: The firmware implements a differential drive algorithm that allows the car to perform 360-degree turns and variable speed acceleration using PWM.

Interaction

• Bluetooth SPP Integration: Verified with the Bluetooth SPP app; the car provides real-time "Obstacle Alert" feedback back to the smartphone screen if equipped with ultrasonic sensors.

Step 1:set up the HC-06：

Set up the HC-06 through the Arduino. Firstly download the code in Arduino. Then download the code in HC-06 to set up it. Serial.begin(9600);This code is to set baud rate. Serial.println("AT"); Serial.println("AT+NAME=smart car"); This is to confirm its name. Serial.println("AT+ROLE=S"); This is to confirm its model that is salve. Serial.println("AT+PIN=1234"); Set up its password. Serial.println("AT+BAUD=9600"); This code is to set baud rate. Serial.println("AT+RMAAD"); Clear pairing list.

Step 2: assemble the car's chassis

Assemble the car's chassis.

Step 3:connect each part with wires

Connect each part by dupont lines. You can refer to the following diagram. （The diagram is from another website.）

HC-06

L298

Step 4:Store the code in Arduino

Store the code 2 in Arduino.Then you can input different number using the smart phone to control the car. Then L298 is powered by 12V. And can control two motors by four pins. You cna contorl the high and low of two pins to deside the forward rotation or backward rotation of the motor.

Step5: The app

Download the Bluetooth SPP in the smart phone. Then connect it to HC-06. Then you can easily control the car by input 1-9 to deside different situation of the car.