This project is internally funded with CeDInt sources.
BatNet is a wireless devices network that uses IPv6 as the main communication protocol. This allows the communication among all the different kinds of devices, creating a mesh network with one way out to the Internet through a concentrator device.
Currently, BatNet system includes devices such as: Three and one phase consumption meter, environment multi sensor, outdoor and indoor lighting controller, remote switching plug with consumption meter and LED RGB lamps controller among others.
Wireless communication is based on the IEEE802.15.4 standard for the physical and medium access control levels. Right after, the specification 6LoWPAN (IPv6 for Low power Wireless Personal Area Networks) is used as an adaptation layer for IPv6 on the network level. Finally, on the application level, CoAP is used as a lighter than HTTP version for text transmission.
Modular architecture of BatNet nodes
There are two kinds of nodes within the network:
- Standard node: In addition to being part of the network, these nodes manage the different control and monitoring systems for: electric variables (BatMeter, BatPlug, BatSwitch), environmental (BatSense) and for illumination (BatStreetLighting, BatDimmer, BatAmbientLight, BatLEDs).
At the same time, the standard nodes may be classified in two types, depending on their behavior within the network:
- Repeater node: These are network nodes but also work as repeaters for the other nodes, allowing the expansion of the network area as a mesh.
- Leaf node: These uniquely act as network nodes.
- Border Router node: It takes charge of connecting BatNet with any other IPv6 network, allowing connections with both devices and external clients. It is meant to be a low process capability and consumption device.
The access to network devices (either for collecting data from sensors, or for sending orders to the actuators), may be done through two different ways:
- BatLink: It is a micro-computer (BeagleBone) with a Border Router assembled. This allows tunneling all the IPv6 traffic through an IPv4 tunnel (if necessary) to ease the access to the BatNet network remotely through internet and execute directly inside the
- BatLink monitoring applications, where can be stored big amount of data.
- BatMP: It is a software platform based on Java which enables the cooperation of users and applications with BatNet devices through a REST interface. It allows total management of BatNet and also the development of new application and services.
- IEEE 802.15.4: This standard specifies both physical and Medium Access Control for wireless low data rates personal area networks. It has been chosen the 2,4GHz band due to its many channels and international use.
- 6LoWPAN: The working task group 6LoWPAN (IPv6 over Low power Wireless Personal Area Networks) from IETF describes how to adapt IPv6 packets to IEEE802.15.4 based networks. Among others, it adapts the packets size and resolve addresses.
- IPv6/RPL: It is clear that IPv6 is to replace IPv4 soon, because of the lack of IPv4 addresses claim for the IPv6 128-bits ones. RPL (IPv6 Routing Protocol for low power and lossy networks), defined by ROLL group from IETF, optimizes the traffic and minimizes the routing states.
- UDP: UDP (User Datagram Protocol) matches the needs of these kind of networks due to its characteristics (simple, stateless and small headers).
- Communication interface CoAP: CoAP (Constrained Application Protocol), is an adaptation of the application level protocol HTTP for low resources devices and networks. Thanks to this, the RESTful paradigm can be used within this kind of networks.
BatNet devices run Contiki, an open operating system developed by the SICS (Swedish Institute of Computer Science) and designed especially for devices with constrained resources (limited memory and low process capability). Among others functionalities, Contiki provides an implementation of TCP/IP stack and an adaptation of the IEEE802.15.4 with IPv6/RPL.
Devices may be programmed either physically (ISP or serial interface) or remotely using OTAP (Over The Air Programming).
This Project has been totally developed by CeDInt-UPM and has evolved according to the needs and the ideas which arose on the way.
Below are described the developed devices:
Intelligent lighting of Montegancedo campus.
Nearly one hundred pedestrian lampposts have been replaced from sodium vapor to dimmable LED technology and BatStreetLighting devices have been installed in each and every lamppost to provide individual control. Two networks have been configured with different physical channels to ensure reliability and load of the coordinating nodes to ensure response time. Devices have been programmed to switch on when detected illumination reach a threshold and not at a given time. In the on state, they work by defaulr in low power mode (dimmed to 10%) unless presence is detected in which case, they gradually change to 100% and inform the neighbor lamppost in order to anticipate the lighting to the pedestrian before is detected. When presence is no longer detected, they gradually come back to the low power state. The energy savings measured provided by the system exceed 80%.
Consumption Monitoring of greenhouses of the Plant Biotechnology and Genomics Research enter (CBGP)
A BatNet network of 63 BatMeters has been implemented to measure the consumption of the greenhouses and plant grow chambers and machinery used by the center in an extremely detailed way. The objective is twofold first to understand how energy is distributed among different systems and experiments, and second to demonstrate the wireless technology in dense node installations and heavy use electric distribution pannels. 350 power lines are beeing monitored individualy providing information of consumption and 7 more parameters of all different devides and machines of the instalation.
One module of the green house has been installed with 25 dimmable LED light points with individual BatDimmers and a sensor network of 10 BatSense devices. This allows to individually control in this module the amounts of light received by the plant, and to cover different lighting needs within the same module, something that is very difficult or impossible to do with traditional lighting systems. We also monitor amount of light received, temperature and humidity in 10 different places of the module. An application has been developed to program different scenes that automate the dimming levels of the lamps with the lux measured in the plant trays.