Components Required
Components- 1Bluetooth Module HC-05 x 1
- 2Arduino UNO x 1
- 312V 1.5A Adaptor x 1
- 4Power Switch x 2
- 5Battery Level Indicator x 1
- 6L298N Motor Driver x 1
- 7Jumper Wires x 50
- 8BO Motor With Wheel x 2
- 9High Speed DC motor x 1
- 103.7V Lithium Ion Battery x 3
- 11Ultrasonic sensor module x 1
- 12IR Sensor Module x 1
Connection Diagram
Wiring diagramPower Supply
| Component | Pin | Connect To |
|---|---|---|
| 12V Input | + | Power Switch |
| 12V Input | - | GND |
| Power Switch Output | + | Arduino VIN |
| Power Switch Output | + | L298N 12V |
| Power Switch Output | + | Battery Level Indicator + |
| Power Switch Output | - | Common GND |
Arduino UNO
| Arduino Pin | Connected To |
|---|---|
| VIN | 12V |
| GND | Common GND |
| 5V | HC-SR04, IR Sensor, HC-05 |
| GND | HC-SR04, IR Sensor, HC-05, L298N |
HC-SR04 Ultrasonic Sensor
| HC-SR04 Pin | Arduino |
|---|---|
| VCC | 5V |
| GND | GND |
| TRIG | D8 |
| ECHO | D9 |
IR Sensor Module
| IR Sensor Pin | Arduino |
|---|---|
| VCC | 5V |
| GND | GND |
| OUT | D7 |
HC-05 Bluetooth Module
| HC-05 Pin | Arduino |
|---|---|
| EN | NC |
| VCC | 5V |
| GND | GND |
| TXD | D11 |
| RXD | D12 |
| STATE | NC |
Mode Selection Switch
The switch selects between Bluetooth Mode and Autonomous Mode.
| Switch Pin | Connection |
|---|---|
| Center Pin | Arduino D13 |
| One Side | GND |
| Other Side | Not Connected (Pull-up used internally) |
Arduino D13 readsLOW → Bluetooth ModeHIGH → Obstacle Avoidance Mode
L298N Motor Driver
Power:-
| L298N | Connection |
|---|---|
| 12V | 12V Battery |
| GND | Common GND |
| 5V | Leave as module output or connect according to jumper configuration (do not power Arduino from it unless intended) |
Control Pins:-
| L298N | Arduino |
|---|---|
| ENA | D6 |
| IN1 | D2 |
| IN2 | D3 |
| IN3 | D4 |
| IN4 | D5 |
| ENB | D10 |
Motors
Left Motor (M1)
| Motor Wire | L298N |
|---|---|
| Wire 1 | OUT1 |
| Wire 2 | OUT2 |
Right Motor (M2)
| Motor Wire | L298N |
|---|---|
| Wire 1 | OUT3 |
| Wire 2 | OUT4 |
If a motor rotates in the wrong direction, simply swap its two wires.
Battery Level Indicator
| Battery Indicator | Connection |
|---|---|
| + | 12V |
| - | GND |
Common Ground
All of these must share the same GND:
Arduino UNOL298NHC-05HC-SR04IR SensorBattery12V SupplyComplete Arduino Pin Mapping
| Arduino Pin | Connected Device |
|---|---|
| D2 | L298N IN1 |
| D3 | L298N IN2 |
| D4 | L298N IN3 |
| D5 | L298N IN4 |
| D6 | L298N ENA |
| D7 | IR Sensor OUT |
| D8 | HC-SR04 TRIG |
| D9 | HC-SR04 ECHO |
| D10 | L298N ENB |
| D11 | HC-05 TXD |
| D12 | HC-05 RXD |
| D13 | Mode Switch |
| 5V | HC-SR04, HC-05, IR Sensor |
| GND | All Modules |
| VIN | 12V Supply |
Smart Autonomous + Bluetooth Robot Logic
Power ON│▼Initialize Hardware│▼Check IR Sensor│┌───────────┴───────────┐│ │Unsafe Surface Safe Surface│ │▼ ▼Stop Robot Read Mode Switch│┌───────────────────┴───────────────────┐│ │Auto Mode Bluetooth Mode│ │Read Distance Wait for Commands│ │┌─────────┴─────────┐ F/B/L/R/S│ │Obstacle No Obstacle│ │▼ ▼Stop Robot Move Forward│▼Move Backward│▼Turn Right│▼Continue Navigation
Code & Program
Dual operation modes: Autonomous navigation and Bluetooth manual control. Obstacle avoidance: Uses an HC-SR04 ultrasonic sensor to detect obstacles within 25 cm and automatically avoid them. Manual control: Receives movement commands (F, B, L, R, S) via an HC-05 Bluetooth module. Safety mechanism: An IR sensor has the highest priority and immediately stops the robot when it detects an unsafe condition. Mode switching: A hardware switch selects between autonomous and manual modes, with a controlled stop before changing modes. Speed control: PWM outputs on the L298N enable pins regulate the left and right motor speeds independently.
Source Code
Download the complete source code for this project.
Smart Vacuum
Watch full build video
Ready to build?
Get every component for this project delivered to your door.