As far as I am aware, off-the-shelf batteries are not designed for long lifetime use, in the order of years. Yet they are being used for long term deployment in WSN. I’ve seen theoretical projections of how long low power wireless motes can last. But there still seems to be an unknown quantity on the profiles of batteries, when used for a long time by wireless motes, drawing µA current…
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More standardisation activities, this time to set sensor net standard for process control. Having a big say on how wireless sensor networks (WSNs) can be used in a practical way at the moment, several industries from the automation and control sectors are trying to muscle in their own standards for WSNs. Notably the 30,000-member ISA trade group which focuses on factory automation.
On the other hand there are industries from the PC data side that try to extend Internet Protocol (IP) to WSNs. For example IETF’s Routing over Low-power and Lossy Networks (Roll) group which is pursuing a standard way for control and sensor nodes on Bluetooth, Wi-Fi and 802.15.4 nets to link to the broader Internet, interestingly backed by Cisco Systems.
Related blog posts:It wasn’t that long ago when 3G network was touted to give mobile users broadband experience on the move. Till today, even though I have 3G capabled mobile phone, I still am not experiencing the “web surfing” experience I enjoy 7-8 years ago using my desktop machine. Whereas the speed of fixed line broadband has increased considerably over these years, the bandwidth you get from 3G connection has not really managed to catch up. It is a wonder if 3G can ever live up to the expectation they once jazzed up years ago.
Then there is the multi-hop ad hoc networks which threatened to compete with network operators’ infrastructure, extending the coverage of the last mile access and potentially squeezing the core networks. Thankfully after the telecom bubble, the hype surrounding this was much less than the 3G circus, but it is a networking concept that has captured many’s imagination initially. To be honest, it is still a very unique networking concept, and has shown to work, but just has not been good enough, yet again. It is more realistic at the moment to use it in a more static environment than trying to get it to work satisfactorily in an environment where every nodes can potentially move around.
So is the wireless sensor network. It seems to also come to a stage where the hype is slowly fading away and people are getting back to basic. Rather than trying to capture investors’ attention by telling them that, “hey, these little motes can be thrown out of the aeroplane and they can ’self-configure’ to form a network and propagate monitoring information back to the base station”, people are more prudent and use it in a more sensible way in the form of Zigbee network with a star topology for example. Multi-hop, long lifespan wireless sensor network is still some way from being ready for deployment.
Anyway the point is new technologies will keep emerging all the time. It’s good to feel excited about new technologies. But unless you are in the position to do something about the technologies, there’s no need to get overly distracted by the hype surrounding it, created by marketing people who don’t know that much about the technologies, yet somehow manage to leave a bad taste in many people’s mouth.
Related blog posts:ZigBee modules are readily available nowadays. Assuming that they can all live up to their expectations, providing the network stack that allows wirelss sensor motes to be easily organised into a network fit for deployment, we will be seeing a host of software applications to be developed for wireless sensor networks this year. My concerns with ZigBee are, forget about large-scale or maybe even medium-scale sensors deployment, the ease of deployment of a ZigBee wireless sensor network and the lifetime of the network. Remember, there were a lot of hypes around multiple hops wireless ad hoc networks not that long ago when the concept was first put into trial. Don’t get me wrong, the potential of such networks is still there. But, under the constraints of current underlying technologies, the deployment of these networks for the applications initially expected of them is not as simple as the name of these networks would have you believed. Work is currently still on-going in this area, so I won’t be surprised if the ZigBee stack is still someway away from being ready for some serious applications. What I’m more interested in is better tools to diagnose a wireless sensor network as at the moment troubleshooting a network of these little motes when something goes wrong is still painfully difficult.
Related blog posts:Fast forward a couple of years and imagine that we now have the “perfect” wireless sensors, what do we foresee them to add to our life? Consider the scenario where these sensors are dotted everywhere, can last an awful long time, hardy, reliable, with their position known (either by themselves or by somebody else), cheap enough to be disposable in an environmental friendly way after use, can be re-tasked or upgraded easily, etc, etc. There are going to be an awful lot of physical information that will be captured by these devices. So now what? What do we do with these information?
Like our 5 senses, we don’t need every single piece of information we sense all the time. So the capability to boil these raw information down to something meaningful and useful will be crucial. But that’s only the start. We need to be able to close the loop. As in we need to be able to do something to the information we possess, however important and useful they are. Take for example temperature sensors dotted around in a room. We have all these information about the temperature of the room. Temperature near the window is lower than the rest of the room. There’s big temperature variations across the height of the room, as the air vent is located at the ceiling. Based on these information, can we, or more precisely in this case the air vent, do something about improving the comfort level of the people who occupy the room? Maybe not, as some may argue that temperature alone is not enough. The air vent is too old-fashioned and we can’t control in which direction we want the air to blow. And the definition of comfort could well be very different for different people. But the important thing is to be able to at least control the room temperature based on the feedback from the sensors. So the key is a closed-loop process. But the loop need not be immediate, where say the air vent will be immediately controlled. Buildings or facilities may be improved based on the information gathered over time. Beautiful. Isn’t it?
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