Smart Parking

Ultrasonic Sensors in Smart Parking: Principles, Applications, and Advantages

Working Principle:

Ultrasonic sensors in smart parking systems detect parking space occupancy by emitting ultrasonic waves. The sensor measures the time difference (Δt) between the emitted signal and its reflection from a vehicle or obstacle. Using the speed of sound in air (v ≈ 340 m/s), the distance to the object is calculated using the formula:

Applications in Parking Space Detection:

Parking Space Status Detection

Installation: Ultrasonic sensors are mounted on the ceiling, typically 2.5-5 meters above the parking spot.

Detection Logic:

Vacant: If the sensor detects the distance from the ceiling to the ground (H), the space is vacant.

Occupied: When a vehicle enters, the sensor detects the distance from the ceiling to the car's roof (h), which is shorter than H, indicating the space is occupied.

Anti-Interference: Multiple sampling and threshold filtering are used to minimize interference from dust, lighting, or adjacent vehicles.

Multi-Space Network Detection

In large parking lots, ultrasonic sensors are connected via RS485 or LoRa wireless communication, transmitting status data to a central control system, which processes it to create a real-time parking map.

Integration with Smart Parking Systems:

Real-time Parking Guidance

On-site: LED screens at key locations show available spaces, driven by real-time sensor data.

Off-site: Users can reserve spaces via an app, with navigation provided to the reserved spot upon arrival.

Parking Fee and Management

Time-based Charging: The system starts timing when a vehicle occupies a spot and calculates parking fees based on duration.

Abnormal Alerts: Alerts are sent if a vehicle stays too long or if the sensor malfunctions.

Data Analysis and Optimization

Traffic Analysis: Data from sensors help optimize space allocation and pricing strategies.

Maintenance: Sensors monitor their own status and send repair notifications if they malfunction.

Advantages of Ultrasonic Sensors in Smart Parking:

Low Cost: Compared to lidar or cameras, ultrasonic sensors are affordable and suitable for large-scale deployment.

Strong Anti-Interference: Ultrasonic sensors operate well in various environments, unaffected by lighting, color, or weather conditions.

Easy Installation: Ceiling-mounted sensors don’t require floor or wall modifications, reducing installation time and operational disruption.

Low Power Consumption: With intermittent operation, ultrasonic sensors have low energy consumption, making them suitable for battery or PoE power.

Integration with Other Technologies:

IoT Integration: Ultrasonic sensors connect to the cloud via IoT gateways, enabling remote monitoring and management of parking data.

AI Integration:

License Plate Recognition: Sensors assist with plate recognition when cameras fail due to angle or obstruction.

Parking Prediction: AI algorithms analyze historical data to predict parking space availability, offering users more accurate recommendations.

Typical Case Studies:

Shenzhen Commercial Parking Lot: Over 2,000 ultrasonic sensors reduced the average search time from 15 minutes to 3 minutes, increasing space utilization by 20%.

Hangzhou Smart Park: Combined with AI, ultrasonic sensors automatically alert for long-term parking, reducing the issue of “zombie cars” occupying spaces.