Aparcamiento inteligente y vigilancia medioambiental en una de las mayores WSN del mundo

 

Smart Parking - LoRaWAN / Sigfox (doble radio) En carretera, superficie → Próximamente en 2016.

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En respuesta a la demanda ciudadana e impulsado por tres aspectos principales de la gobernanza, se está imponiendo un nuevo concepto de ciudad para ofrecer una mejor calidad de vida a los ciudadanos, minimizar el impacto ambiental y reducir costes. El sitio Escenario de aparcamiento es uno de los problemas más importantes presentes en una ciudad en el que intervienen los tres factores. En todo el mundo, la contaminación atmosférica y las carreteras congestionadas deprecian la calidad de vida, lo que se traduce en pérdida de tiempo para los conductores y despilfarro de combustible. La Comisión Europea calcula que las pérdidas económicas debidas a los retrasos del tráfico ascienden a 150.000 millones de euros al año en Europa. La necesidad de buscar aparcamiento es un factor importante de la congestión generalizada y una de las principales causas de estrés para los automovilistas. Según cálculos realizados en Barcelona (España), un millón de conductores pasan una media de 20 minutos al día buscando aparcamiento, lo que produce 2.400 toneladas de emisiones de CO2. Proyecto Smart Santander SMART SANTANDER proyectoque ha sido desarrollado por varias empresas e instituciones, entre ellas Telefónica I+D y Universidad de Cantabriatiene como objetivo diseñar, desplegar y validar en Santander y su entorno una plataforma compuesta por sensores, actuadores, cámaras y pantallas para ofrecer información útil a los ciudadanos. 1125 Waspmotes  se han desplegado para controlar diferentes parámetros como el ruido, la temperatura, la luminosidad, el CO y el libre aparcamiento ranuras.

Fig. 1. - Ubicación de SmartSantander

Unique in the world, SmartSantander is really a city-scale experimental research facility in support of typical applications and services for future Smart Cities. This exceptional experimental facility is sufficiently large, open and flexible to enable horizontal and vertical federation with other experimental facilities, and to stimulate development of new applications by various types of users including experimental advanced research on Internet of Things (IoT) technologies, based on the realistic assessment of users’ acceptability tests. The project envisions the deployment of 20,000 sensors in the European cities of Belgrade, Guildford, Lübeck and Santander (12,000), exploiting a large range of technologies. Within this article we will focus on Santander deployment. If you want to know more about Belgrade deployment, please visit this estudio monográfico. La Solución This project can be better explained with the following diagram, showing the nodes, the networks created and their connection to the cloud. One of the main challenges we encountered during the SmartSantander project was the Over-the-Air-Programming (OTAP) development needed to program all the nodes wirelessly and remotely. Libelium collaborated with the University of Cantabria to improve the OTAP system, creating a more robust network that can be upgraded at any time from any place. In this project 1,125 Waspmotes en distintos puntos de la ciudad de Santander para medir cinco parámetros diferentes:

• Temperatura
• Luminosidad
• CO
• Ruido
• Plazas de aparcamiento gratuitas

Estos cinco sensores se conectan al Waspmote a través de las tarjetas Gases Sensor Board (sensor de CO), Parking Sensor Board (aparcamiento), Smart Cities Sensor Board (sensor de ruido) o directamente al Waspmote (temperatura y luminosidad).

Each sensor has two radios for communicating at 2.4GHz (except for the parking sensors). On one end of the communication, DigiMesh is the protocol selected to send the environmental information. On the other hand, IEEE 802.15.4 protocol is used to carry out experiments within the network. All the nodes within the SmartSantander network can be used to test new algorithms without any downtime, while citizens still receive information about their environment. If any of these five parameters goes above a certain threshold, the system analyzes the information and may react by sending an alarm to the central node (the wireless gateway, Meshlium, in this case). To know where a sensor is located, each Waspmote can integrate a global positioning system (GPS) that delivers accurate position and time information. Libelium offers several wireless modules for the comunicación por radio:

Modelo	Protocolo	Frecuencia	Potencia TX	Sensibilidad	Gama*
XBee-802.15.4	802.15.4	2,4 GHz	1 mW	-92 dB	500 m
XBee-802.15.4-Pro	802.15.4	2,4 GHz	63 mW	-100 dBm	7000 m
XBee-ZigBee	Zigbee-Pro	2,4 GHz	2 mW	-96 dBm	500 m
XBee-ZigBee-Pro	Zigbee-Pro	2,4 GHz	50 mW	-102 dBm	7000 m
XBee-868	RF	868 MHz	315 mW	-112 dBm	12 km
XBee-900	RF	900 MHz	50 mW	-100 dBm	10 km
XBee-XSC	RF	900 MHz	100 mW	-106 dBm	12 km

Fig. 4. - Distancia alcanzada en función del protocolo

We can reach up 40 km with Line of Sight (LOS) conditions using the 868MHz module. The high performance of Waspmote makes the readings really accurate and the transmission is highly reliable and flexible, placing the nodes at an average separation of 1,5 km. It is also possible to transmit the data via GPRS/3G, as a secondary radio module for better availability and redundancy in situations when it is critical to ensure that the message is received, as for fire alarms. Because the GPRS/3G module is quad-band it can operate in four different frequency bands and  supports any cellular connection provider, making it able to work all over the world. In this way, the project we are describing is suitable for any country. One of the main characteristics of Waspmote is its low power consumption:

• 9 mA, modo ON
• 62 μA, modo de espera
• 0,7 μA, modo de hibernación

Para ahorrar batería, el Waspmote pasa la mayor parte del tiempo en modo reposo. Después de unos minutos (programables por el usuario), Waspmote se despierta, lee de los sensores, implementa la comunicación inalámbrica y pasa de nuevo al modo de reposo. Proceso de implantación El despliegue de la red de sensores inalámbricos se llevó a cabo mediante IDOM y TTI Norte, two Spanish companies specialized in telecommunications and engineering. First, a coverage study was done to know where to place sensors and repeaters to maximize the area covered by the project. The coverage study divided the city in 22 different zones. Each zone had a Meshlium wireless gateway to gather the data from the sensors: the number of sensors depended on the area to cover. The process involved deploying zone by zone, to create independent networks that work on different frequency channels without any interference from one another. First, the sensors were calibrated to check that their output was accurate. Once they had been calibrated, they were randomly tested to pass Libelium’s quality control. Each node was placed within an IP-65 box that could be deployed under the harsh conditions of the city of Santander. The sensors were placed on light lamps or building fronts, trying to minimize the visual impact on the city. Each box contains the electrical equipment necessary to be connected to light lamps without any danger to public installations. They are connected to the line through residual current circuit breakers and fuses to avoid electrical problems. A transformer adapts the current and voltage to power the nodes. On the other hand, Waspmotes were deployed in different locations within the city of Santander, measuring magnetic field to detect whether a parking slot is free. Magnetic field sensor is connected to Waspmote through the Smart Parking Sensor Board. These sensors detect the variation of the magnetic field generated by a car parked on it. To do that, the sensor is buried under the surface of the road inside a waterproof casing. The hole is closed using a specific material and it is barely detectable at a glance.

Fig. 8. - a) Waspmote enterrados bajo la calzada b) Pantallas para indicar las plazas de aparcamiento libres

Each Meshlium gathers the data from all the sensors within its zone, stores the data in a MySQL database and sends the information to the Internet through a 3G or Ethernet connection. Meshliums are placed on the top of buildings to maximize the area covered. As a result of this installation, environmental parameters can be monitored for further study and citizens can also know them thanks to real-time maps available for viewing. Furthermore, the SmartSantander project is a large-scale network for experimentation that allows researchers from all over the world to test different algorithms in a real environment. If you are interested in Waspmoteestaremos encantados de ayudarle a diseñar su sistema. Puede solicitar una oferta de Waspmote aquí.