Bluetooth Controlled Car Arduino Based

This project is a simple and exciting two-wheel drive (2WD) robotic car built using an Arduino Nano and controlled via Bluetooth from an Android smartphone. Instead of using a ready-made motor driver module, I designed a custom-built motor driver circuit using the L293D IC, giving me full control over the motor wiring and circuit layout.

The car receives commands via an HC-05 Bluetooth module connected to the Arduino Nano. Using a dedicated Android app, the car can move forward, backward, turn left, right, and stop — all controlled wirelessly in real time.

This project is ideal for hobbyists and beginners looking to learn more about Arduino programming, Bluetooth communication, and basic electronics through a hands-on and rewarding robotics project.

You can purchase the complete Autobot car kit used in this project here to get all the mechanical components in one package.

Components Required

1. 1 × Autobot chassis – The main frame of the car for mounting all components
2. 2 × BO motors – Used for driving the rear wheels
3. 2 × Wheels – Compatible with BO motor shafts
4. 1 × Castor wheel – Provides front support and balance
5. 1 × Screws and spacers pack – For assembling the chassis securely
6. 1 × 2A Battery holder – Holds and supplies power using two cells
7. 2 × Lithium-ion cells – Rechargeable batteries to power the circuit
8. 1 × Customized Autobotix circuit board – Custom PCB based on Arduino Nano and L293D motor driver
9. 1 × HC-05 Bluetooth module – For wireless communication with smartphone
10. 1 × JST 4-pin wire – For connecting modules neatly and securely

You can purchase the complete Autobot car kit used in this project here to get all the mechanical components in one package.

Before starting the assembly, make sure you have all the mechanical components of the car ready. As shown in the image above, collect the chassis plates, wheels, BO motors, screws, spacers, battery holder, and other necessary mounting hardware. This step will help ensure a smooth and efficient assembly process.

Want to skip the hassle of collecting parts?

🚗 Buy the Complete Autobotix 2WD Bluetooth Car Kit

In this step, mount the BO motor onto one of the side panels using screws. Align the motor shaft with the cutout on the panel, and fix it securely using two screws through the mounting holes on the motor. Make sure the motor wires are facing outward for easy connection later.

Repeat this process for the second motor on the opposite panel.

Now, it's time to assemble the car frame. Take the side panel with the attached BO motor and align it with the slot on the black base panel as shown in the image. Carefully slide the side panel into the corresponding slots and secure it using screws or spacers if needed.

Make sure the motor wires are facing inward toward the base so they can be easily routed later during wiring.

Repeat this step for the other side panel in the next step.

Once both side panels are properly mounted to the base, it's time to secure the top frame. Take the curved black panel (top panel) and align its slots with the tabs on the yellow side panels.

Gently press the top panel down into the side panels until it locks firmly into place. Ensure both BO motors and wires are properly enclosed and that nothing is obstructing the fit.

In this step, the middle side panels are inserted vertically between the upper panel and the base panel. Carefully align the notches and slots provided on both the upper and base panels, and gently slide the middle side panels into place so that they are firmly seated. It is important to ensure that both side panels are parallel and symmetrical to maintain the structural balance of the assembly. Also, double-check the clearance for the wires to ensure they can be routed properly without any obstruction. Make sure the panels are fully inserted and not slanted, as any misalignment at this stage can cause issues during the fitting of the remaining components.

In this step, the front eye component is attached to the front side of the car chassis. Although it includes slots designed to hold an ultrasonic sensor, the current version of the project does not utilize the sensor. However, this feature can be used in an upgraded version if obstacle detection is required. Align the component with the designated cutouts on the front panel and securely insert it into place. Ensure it fits properly and is firmly held, as this component forms part of the car’s structural frame and can support future sensor installations.

In this step, all the necessary screws are fixed throughout the car’s structure to firmly secure each component in place. Where required, spacers are added between layers or panels to maintain proper alignment and provide structural stability. These spacers help ensure that the chassis remains evenly assembled and allow enough clearance for wiring or future component additions. Make sure each screw is tightened appropriately, but avoid over-tightening to prevent damage to the material. This step completes the mechanical assembly of the car chassis, making it ready for further electronic integration.

In this step, the wheels are carefully placed onto the shafts of the BO motors on both sides of the car. Ensure that the wheels are firmly pressed onto the motor shafts so that they fit snugly and rotate without slipping. This provides the car with the necessary traction for movement. Make sure both wheels are aligned properly to maintain balance and allow smooth, straight motion. With the wheels attached, the basic mobility setup of the car is now complete.

In this step, the castor wheel is mounted onto the front side of the base plate. The castor wheel provides support and balance to the car, allowing it to turn smoothly while maintaining stability. It is positioned at the front side of the base, opposite the side where the BO motors and wheels are attached. Secure the castor wheel using appropriate screws, ensuring it can rotate freely. This completes the three-wheel configuration of the car chassis.

At this stage, gather all the electronic components required for the project, including the Arduino Nano, L293D motor driver circuit (custom-built), HC-05 Bluetooth module, and jumper wires. Begin by connecting the BO motors to the output pins of the L293D motor driver circuit. Ensure that the motor wires are properly inserted and securely connected to avoid any loose contact during operation. Double-check the polarity of the connections so that the motors rotate in the correct direction according to the commands from the app. With the motors connected, you’re ready to move on to wiring the rest of the electronics.

In this step, connect the HC-05 Bluetooth module to the Arduino Nano to enable wireless communication with your Android device. Connect the VCC pin of the HC-05 to the 5V output of the Arduino, GND to GND, TXD to the RX pin of the Arduino (D0), and RXD to the TX pin (D1).

In this step, connect the batteries to the battery holder and power up the circuit. Turn on the switch on your custom-built circuit to supply power to all components. Carefully observe the system to ensure that power is being distributed correctly — the Arduino Nano should turn on, and the HC-05 Bluetooth module's LED should start blinking rapidly, indicating it's in pairing mode. Also, verify that there is no loose wiring or unusual heating.

Now that the circuit is powered on and the HC-05 module is blinking, it’s time to pair it with your smartphone. Open the Bluetooth settings on your phone and search for nearby devices. You should see a device named “HC-05” in the list. Select it to begin pairing. When prompted, enter the default pairing code — usually 1234 or 0000 — and confirm the connection. Once successfully paired, the blinking LED on the HC-05 will change to a steady light, indicating a stable connection.

In this step, open the Bluetooth control car app on your Android smartphone. Once the app is launched, tap the scan or connect button to search for available Bluetooth devices. From the list of detected devices, select HC-05 to establish the connection. After a successful connection, the app will be ready to send commands to the car using the pre-set control buttons such as Forward, Backward, Left, Right, and Stop. With everything connected, you're now ready to control your Arduino-based robot car wirelessly!