Project #4
the Servo Smart Barrier
The Servo Smart Barrier is a fully functional toll gate automation system powered by an ultrasonic sensor and servo motor. When a vehicle comes within range, the system deactivates the blue LED and activates the red LED, signaling the toll gate to open. The buzzer provides an audible alert while the servo motor lifts the barrier for 1.5 seconds, ensuring smooth and efficient operation.
Technical Breakdown
Schematic Diagram
Components Used:
1. Arduino UNO Board x1
2. SG90 Micro Servo
3. HC - SR04 Ultrasonic Sensor
4. Piezoelectric Buzzer
5. 3mm LEDs (Blue and Red)
6. 220Ω Resistors x 3
7. 1kΩ Resistors x 1
8. Jumper wires
Key Features
1. Real-time Distance Measurement
The system continuously monitors the distance of an approaching vehicle using the HC-SR04 ultrasonic sensor. This allows for instant feedback, ensuring that the toll gate reacts the moment a vehicle crosses the distance threshold.
2. LED Status Indicators
The project features two LEDs—blue and red—that provide visual feedback on the toll gate's status. The blue LED signifies that the gate is closed, while the red LED illuminates when the barrier is lifted, making the system easy to monitor at a glance.
3. Automated Servo-Controlled Gate
At the heart of the system is a servo motor that lifts and lowers the toll gate based on real-time distance data. The smooth and timed operation ensures a seamless passage, with the gate resetting automatically after 1.5 seconds.
4. Audible Alerts with Piezo Buzzer
The buzzer adds an auditory alert to the system, beeping repeatedly when a vehicle passes the ultrasonic sensor and the toll gate begins to open. This helps improve awareness and enhances the system’s reliability in noisy environments.
5. Timed Gate Reset
After the car has passed, the system automatically resets after 1.5 seconds. The buzzer stops, the red LED turns off, and the blue LED comes back on, ensuring a smooth operation for the next vehicle.
Demonstration Video
In this video, I’ll show the Servo Smart Barrier in action. As I zoom in on the components, you’ll see the ultrasonic sensor, LEDs, piezo buzzer and and servo that form the core of the project. To demonstrate how the system works, I’ll be using the red fire truck, deservedly named the Henry Mobile, as it approaches the toll gate. Watch as the sensor detects the Henry Mobile, turning off the blue LED and switching on the red LED while the buzzer starts beeping. The toll gate barrier then lifts, allowing the car to pass. This sequence repeats six times to showcase how the system consistently reacts. You may not hear the buzzer very clearly because the sound of the truck’s tires is closer to the microphone, but rest assured, it’s working hard!
Demonstrating the Servo Smart Barrier as the toll gate automatically reacts to an approaching vehicle.
Notes
Building this was an exciting progression from my earlier Proximity Pulse project.
With this project, I was able to integrate four different components—an ultrasonic sensor, servo motor, LEDs, and a piezo buzzer—the most I’ve done in a single project so far, and it came out successfully. While the Proximity Pulse used a single output method (LEDs) to provide proximity feedback, Servo Smart Barrier steps it up with three simultaneous feedback channels: visual (LEDs), auditory (buzzer), and physical (servo). Each element works together to create a dynamic, real-time response as the system detects an approaching vehicle.
Throughout the process, I gained valuable experience managing multiple outputs in parallel, particularly with timing the servo’s operation alongside the LED status changes and buzzer signals. This project allowed me to refine my understanding of how different components can interact in a more complex automation setup.
Funny enough, I used my trusty red fire truck—the Henry Mobile—as the test car during the demo. The Arduino 101 board, which once served as a test object in my Proximity Pulse, has now officially retired from its role as a stand-in model!
Looking ahead, I’m excited to explore additional upgrades, such as adding a delay period between the car's detection and the toll gate opening, perhaps accompanied by different LED or buzzer patterns. These ideas will help make the system even more responsive and adaptable.
Check out my other projects here!