In modern cities, accessibility and transport efficiency are important indicators of urban operational performance. Regarding transportation innovation, three smart cities such as Vienna, Austria, Barcelona, and Tokyo, Japan are typical representatives.

Recently, Mercer Consulting announced 10 cities with the highest quality of life in the world in 2019. For the tenth time, Vienna has become the most livable city in the world. In addition to the health care system, cafes and rich cultural life attracting tourists, the city's smart public transport system allows visitors to easily navigate through every corner of the city. Vienna has 5 metro lines, 28 tram lines and 128 bus lines. Residents can easily access real-time information on a variety of vehicles via the smartphone app Quando, which will also alert users before the next tram, subway or bus departure. In addition, users can also plan travel services via WienMobil, whether it is public transportation. Tools, walking, cycling, taxiing or shared cars, users can easily book and pay with the app. Smart travel is making the city work harder to become smarter, more humane, more sustainable, and even more livable.

 A city of more than 5 million inhabitants in Barcelona has received nearly 9 million visitors in recent years. The subway system carries more than 390 million trips a year. The intelligent transportation system has become the basis for the smooth operation of the city. In addition to efficient public transport, Barcelona also has a network of intelligent traffic lights, and Barcelona has implemented a variety of intelligent transportation solutions, including interactive touch screen information display at the bus station. The smart parking sensor allows the driver to find nearby free parking spaces. The bicycle sharing system Bicing And share an electric scooter rental.

Tokyo, Japan is one of the world's most densely populated cities with more than 13 million inhabitants. The city also receives many tourists from all over the world every year. But under such a large flow pressure, the efficiency and ease of use of its transportation system has been widely praised. This is due to the IoT technology. With the help of IoT technology, subway operators can collect and analyze data on device status in real time, identify defects, predict failures, and schedule repairs. This "state maintenance" approach transforms inefficient periodic maintenance systems into intelligent maintenance systems.

With the increasing urban population and the ever-increasing size of cities, how to build efficient, comfortable and fast-moving transportation systems has become a major challenge for urban management organizations. In recent years, the cost of sensors has continued to decline, the communication speed has been continuously improved, and more data has been collected and analyzed in real time. The Internet of Things is changing the management and operation of urban traffic. An ultrasonic sensor for parking lots is introduced below.

The parking lot is an extremely important part of the urban transportation infrastructure. There are so many domestic vehicles, and the limited number of parking lots has become in short supply. Most of the current parking lots, the parking space indications are not clear, and the parking space usage is not clear, so the owners are Blindly turned in the parking lot. At this time, according to the continuous update and iteration of the current science and technology, more requirements are put forward for the construction of the parking lot. In addition to the requirement of the number of parking spaces, the parking lot is required to have intelligent guidance, and the use of the parking space has an intuitive display. It will be a very pleasant experience.

Recently, Chongqing China Zhigu¡¤Kechuang Center launched the first inclined parking system, becoming the country's first inclined parking garage. In the garage of nearly 400 square meters, after the renovation of 24 parking spaces, 40 vehicles can be parked. Each parking rack is tilted at 32 degrees and arranged neatly in a straight line. The tilt angle of the parking rack is generally 28 to 32 degrees, which can be adjusted according to different height garages. At the same time, the inclined parking system will be linked with the first AGV intelligent parking robot in Chongqing to create a truly intelligent unmanned garage.

It is understood that in this system, the plane inclined intelligent parking system is composed of a parking rack, a power system, a hydraulic system, an intelligent intelligent control system, and a safety auxiliary system. Each parking rack is equipped with 8 detectors and sensing probes, which can monitor the position of the vehicle in real time and respond to and prompt the surrounding environment to assist the vehicle to return to safety and avoid various accidents that may occur during parking. Specifically, the plane tilting intelligent parking rack is equipped with 12 proximity switch sensing devices and 8 ranging radars, which can realize automatic parking and obstacle avoidance. In order for these applications to work properly, they need a reliable ultrasonic sensor to detect the position of the vehicle.

The ultrasonic ranging module is a product for measuring the distance. By transmitting and receiving ultrasonic waves, using the time difference and the sound propagation speed, the ultrasonic wave propagates in the air at a speed of v, and the measured transmitting and receiving echoes are recorded according to the timer. The time difference ¦¤t, the distance S of the emission point from the obstacle can be calculated, that is: S=v¡¤¦¤t /2 to calculate the distance from the module to the obstacle ahead.