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How Wireless Meshing Could Save Energy

Posted by timothy on Mon Aug 09, 2004 06:22 PM
from the 23-percent-is-a-bunch dept.
Wireless Networking Hardware Technology
An anonymous reader writes "EE Times reports that the future of industrial automation lies in wireless mesh sensor networks. From the article: 'It is the holy grail of the factory floor: hundreds of sensors wirelessly connected, monitoring motors for problems and drastically reducing energy consumption -- all with the precision and rhythm of a philharmonic orchestra.' (Other articles here(1), here(2), and here(3).)"
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  • Saving energy... (Score:4, Interesting)

    by ackthpt (218170) * on Monday August 09 2004, @06:28PM (#9925078) Homepage Journal
    All I need is some sort of antenna system, tuned to the wavelength of these networks and I could capture the power and run my house off it! :-)

    My dad told me stories of Back In The Day(tm) when AM radio stations would broadcast at 300,000 watts, or more, and streetlights would be lit by the radiant energy. Can't imagine that did people much good living near the antennas...

    • The station transmitted to all of Europe via the powerful transmitter site in Marnach on 1439 kHz (later 1440 kHz), 208 metres in the medium wave band. The transmitter pumped out 1300 kW and was Europe's most powerful (only hit by a Russian site which had more power). Radio Luxembourg ceased transmissions from the 208 transmitter December 30. 1991 to be available on satellite and short wave only. Unfortunately CLT decided to close the station at the end of 1992 because it made no money out of the programmes. Luxy returned on the great 208 for one night only - the date when the station's final programme was aired - December 30. 1992.

      • Radio Luxembourg is, however, most famous as the source of the "Luxembourg effect." In 1933, shortly after these powerful transmissions started, its modulation was heard in the Netherlands, mixed with that of a German station on another frequency (1). It was soon proposed that this occurred because Radio Luxembourg's signal was so powerful it was heating the ionosphere, producing a nonlinear condition that mixed the two AM signals (2). This effect has since been studied by the HAARP [alaska.edu] (High Frequency Active

    • The idea of dispersing electricity through radio signals is certainly not new, Nicola Tesla had this design installed in his house. A transmitter that powered all his lights without the need for wiring. I'm not sure if this is the same technology being used here but it sounds similar.
    • yah.

      I've often wondered about the 1/r^3 law for em transmissions. How come radios don't get alot weaker very quickly as you drive away from the radio station?

      If you could power streetlights by the AM transmissions, wouldn't that mean that you could also electrocute yourself by touching any long peice of metal?

  • I, for one... (Score:4, Interesting)

    by ChaosWing (83607) * on Monday August 09 2004, @06:29PM (#9925083) Homepage
    ...welcome our new job-stealing wireless mechanical overlords.

    Seriously, though, this would make my job a whole lot easier...monitoring the operation of a pair of 8MW generators (or a host of other equipment) from a single location vice constantly hopping around from point-to-point looking at every little gage and meter gets real old, real fast.
    • this would make my job a whole lot easier

      You realize, of course, that just means they'd give you more work to make up for what they took away. Right?

      • Not necessarily. If something were to go wrong with the internals of a machine, odds are better that an electronic sensor would detect the problem before the operator would...a problem detected before serious damage occurs is a lot easier to deal with (and would require less work) than one detected when it causes a component (or an entire machine) to fail.
      • Either that or he'd get laid off.
    • this would make my job a whole lot easier ... monitoring ... from a single location ...

      Your job, or the job of the Indian who replaces you?

      /FUD
    • What happens when your packets don't get there because the mesh network doesn't magically heal itself? Or if it just loses the data? Does that 8MW generator explode?

      Mesh networks have been around for years, but have not reached the masses because they just aren't ready. They're fine for experimental [mit.edu] uses, and maybe even for community networks [cuwireless.net], but as industrial sensors? No thanks.

      Use RS422.

  • How secure are such setups? (Score:4, Interesting)

    by LordZardoz (155141) on Monday August 09 2004, @06:30PM (#9925089)
    Given all the slashdot stories about Wardriving and the like, how secure would these networks be? What prevents a competor with a wireless broadcast anteanna from parking in range of your factory, and sending false signals telling your machines to idle?

    END COMMUNICATION
    • I suspect that's part of the "leaky pipe" problem mentioned in the article. One possible way to prevent what you suggest is to use "line of sight" frequencies. But radio isn't my thing, any Hams in the audience with some ideas on this one?
    • For one thing, it would be pretty easy to add security at a higher abstraction level, unless the device had very little processing power indeed.

      For another thing, however, TFA says: "Each sensor node will use an inexpensive microcontroller and wireless-transceiver chip operating with the ISO-802. 16.4 wireless protocol, which involves secure handshaking between nodes.".

      Another thing, I can't help wondering. Why do you end your posts with 'end communication'?

      • Assuming this e-mail address is valid and has a human at the other end...

        I use 'END COMMUNICATION' at the end of my posts for the same reason as people use signatures at the end of their post. Because it amuses me. Because it sounds abrupt and borderline hostile. Because it actually looks like it might belong at the end of a forum post or e-mail.

        That, and its an obscure simpsons quote from the episode where Kang and Kodos run for president.

        But its not that I am that much of a Simpsons fan. It truly i

    • Re:How secure are such setups? (Score:5, Informative)

      by rcw-home (122017) on Monday August 09 2004, @07:12PM (#9925353)
      What prevents a competor with a wireless broadcast anteanna from parking in range of your factory, and sending false signals telling your machines to idle?

      Standardized AES encryption [zigbee.org].

      BTW, I'm pretty sure that the article had a typo - they probably meant IEEE 802.15.4 (aka Zigbee [zigbee.org]), not 802.16.4. The Zigbee FAQ [zigbee.org] has a lot of valuable information about it.

      • Almost correct. You need AES-128 authentication and message integrity checking, not encryption, but ZigBee has both. Encryption merely makes the message private, but authentication ensures that the source address wasn't spoofed, and integrity checking ensures that it hasn't been corrupted or modified before reaching the recipient.

        BTW, the IEEE 802.15.4 spec is available for free download [ieee.org].

  • Our goal is to enable cost-effective wireless networks that are cheap enough for almost any size motor


    Easily done. Just make then in China where all our factories have been relocated.

  • tinfoil mode (Score:1, Insightful)

    by Anonymous Coward
    Worded with a different spin, the tagline could sound all too familiar:

    An anonymous reader writes "EE Times reports that the future of police monitoring lies in wireless mesh sensor networks. From the article: 'It is the holy grail of law enforcement: hundreds of sensors wirelessly connected, monitoring citizens for problems and drastically reducing energy consumption -- all with the precision and rhythm of a philharmonic orchestra.'
    OK, maybe not a philharmonic orchestra -- a bean burrito perhaps.

  • Munchkins...? (Score:5, Informative)

    by nzgeek (232346) * on Monday August 09 2004, @06:34PM (#9925106) Homepage Journal

    This idea strikes me as an implementation or extension of "Munchkins" described in an ancient (1996) paper [ifindkarma.com] by Rohit Khare and Adam Rifkin.

    The idea basically describes very small, low-power devices that can route messages between each other until they find the target device (or a valid route to the target device). I have to wonder [gadgetophile.com] whether new devices like the iPAQ with GSM, WiFi, and Bluetooth are trending towards this behaviour. It wouldn't take a heck of a lot to turn the iPAQ 6340 into a device that can intelligently route incoming packets over any of its connections.

    I'd love to be able to pick up my cellphone, and connect to my PC via a network of industrial sensors built into traffic signals, bus stops or the nearest ATM.

  • Interference? (Score:5, Insightful)

    by Godeke (32895) * on Monday August 09 2004, @06:44PM (#9925169)
    Having installed wired and wireless networking on manufacturing floors I can tell you that before this dream of magic wireless connectivity comes true, these machines will need vastly better RF shielding. We had a bugger of a time getting wireless to work and even wired networks would act up if you were not careful where you placed the wires. (One company ran fiber optic to the floor machines because the interference issue couldn't be resolved satisfactorily: not a cheap way to go).

    So how long will it take to get those machines updated? Well, one of my first jobs out of the U was making a tape punch work on a PC so they could edit programs and load them from paper tape. That was in 1990. I'm guessing that these will be a great concept for someone building a factory floor from scratch, but retrofitting is going to be a big flop.

    • Re:Interference? (Score:5, Interesting)

      by IvyKing (732111) on Monday August 09 2004, @07:35PM (#9925474)
      The folks working on this are very aware of the problems with interference - DOE has been working on factory floor networking for several years (Wayne Manges from ORNL). In addition to interference, you have to contend with Dopler shift and fading as a result of objects moving aroound the floor (variable multipath). For those with radio experience (e.g hams) signal propagation starts to look more like HF (shortwave) than microwave.

      but retrofitting is going to be a big flop

      Actually the whole point of this work is to retrofit the factory floors (or other places using large motors). According to Wayne Manges, you're looking at $20 to $50 per foot to install wiring, so a $200 wireless sensor would be cost effective compared to running wire. The system could pay for itself by flagging one motor that is having problems before it fails - DOE's hope is that you can also tell tha the motor is chewing up electricity at an excessive rate.

      • Where timing is critical, and a dropped packet might mean injury or death, I doubt industrial controls can switch to wireless for some time.Heck, the place would be easy to sabotage unless it changes frequency routine.

        • Re:Interference? (Score:4, Insightful)

          by calidoscope (312571) on Monday August 09 2004, @10:46PM (#9926431)
          I'd agree with you if the wireless mesh was being used for process control.

          In this case, the wireless mesh is being used for monitoring the health of the motor not for active process feedback.

          Car analogy: When driving a car, your primary feedback is what you see out the windows and that's what your attention is focused on 99% of the time. Every now and then, you take a look at the gauges to make sure the engine is running properly (which is what the info on the mesh provides). If the gauges show something amiss, you may have anywhere from a few seconds (pegged coolant temp or no oil pressure) to several hours (or longer) to deal with the problem.

      • Yes, but the $20 to $50 per foot of wiring has generally already been installed. You can't save the $200 for the wireless sensor if you already have truckloads of DCS equipment reading the data, talking to your overly expensive Cimplicity HMI, OPC interface, OSI PI Server, Intellution interface, RSView, etc.

        While there are still manufacturing/power plants out there that are working without automation, I haven't seen one in a while. Nearly all of them have automated teir systems and are currently monitoring

  • Zensys for the home. (Score:3, Insightful)

    by JVert (578547) <`moc.liamtoh' `ta' `yllibnagroc'> on Monday August 09 2004, @06:47PM (#9925198) Journal
    For those interested in this kind of wireless mesh for the home check out zensys. I dont have any links or handy info, I just know they work in the same way and are intended for home automation. Lightswitches, thermostats etc.

  • Intrinsically Safe (Score:5, Interesting)

    by billdar (595311) < y a p> on Monday August 09 2004, @06:50PM (#9925221) Homepage
    Two years ago when I was an ASIC engineer, I would have thought this was a good solution. Having since switched to industrial control systems, I have to say no way.

    Safty and reliability are absolutes in industrial control.

    A machine like a bottler goes down at pepsi, and they are losing $250k/min when that machine isn't running. Or a pharmacutical company drops a batch worth $3 million. And now that I've climbed in or on huge presses, mixing tanks, 6ft. fans, high preasure steam, and poison vapors... I wouldn't trust thier function to a wireless web.

    I can see where this would be great for remote/hazardess sensors and transmittion, but not anytime soon for control. Hell, we still extensivly use rs232 over ethernet.

    • Saf[e]ty and reliability are absolutes in industrial control.

      The focus of this work is is developing systems for monitoring, not control. The wireless technology is to avoid the cost of running wires, the mesh aspect is to minimize the number of access points.

      The technology is no where near established enough for safety critical systems.

  • Sweet! (Score:4, Interesting)

    by pyrrhonist (701154) on Monday August 09 2004, @06:56PM (#9925264)
    Each wireless sensor will operate for years on a single battery charge, but for the future, GE is working on new technology that could harvest the vibrational energy of the motor itself to power the transceivers.

    This is pretty sweet. This way, you don't have to waste more energy by putting a transformer onto the motor's circuit. The best part is that it uses energy that you're normally wasting anyway.

  • Howzat? (Score:4, Interesting)

    by c0dedude (587568) on Monday August 09 2004, @07:00PM (#9925290)
    The electric charactaristics of a machine change when it's broken. I don't really understand how putting sensors everywhere will improve that situation rather than just managing eletronic load. For that matter, doesn't wireless need much energy?
  • all with the precision and rhythm of a philharmonic orchestra

    Didn't John Cage describe an orchestra as an instrument of destruction?

  • By reducing the cost of owning a motor-monitoring system, the DOE hopes to accelerate adoption of the technology and enable nationwide energy savings. The effort is part of its $61 million Industries of the Future initiative to improve energy efficiency throughout strategic U.S. industries.

    This is just another example of our tax money subsidizing large industry. If the US is really a market economy, then allow the market to correct for inefficient use of energy by simply increasing the cost of energy. He

  • Am I the only one that read the title as: "Hot Wireless Meshing" Where's Bender when you need him?
  • Most industrial motors are used to drive steady-state processes, and are always on. Examples, are drive motors used in pulp mills and refineries. I don't see how any amount of mesh network monitoring is going to drastically save electricity for these always-on motors. A small savings might be found by looking for inefficiencies in the way the motor operates (i.e. it needs maintenance). However, I find the claims of 10-20 percent savings by monitoring somewhat questionable.

    For discrestionary motors, like

  • How does this save energy? (Score:3, Insightful)

    by serutan (259622) <doug&geekazon,com> on Tuesday August 10 2004, @02:15AM (#9927125) Homepage
    The main article and here(1) don't say. All the sensor network would do is sense vibration, temperature, etc. But no explanation of how this would help save energy. Here(2) was farked, I mean slashdotted. Here(3) provides clues: "allowing plant personnel to repair or replace motors before their production capacity drops or they fail entirely," and, "the two-way communications network will enable the use of control applications. For example, if a monitoring system is being used on a generator and has sent notification that it is running too hot, the monitoring personnel could issue wireless commands back to the generator for it to turn on its exhaust fan."

    I can see the usefulness of doing these things in terms of fewer breakdowns, but where is the energy-saving tie in, particularly the claim that the sensor system will "increase a motor's efficiency by 10 to 20 percent" ???
    • As the devices "run for years off a single battery", seems unlikely to pose much of a threat, even in aggregate.
    • Will factory workers get an increase in salary to compensate them for working in a hazardous area?

      If the energy is low enough it's probably no worse than that green tan you've been developing from fluorescent lights. I'm miffed about all the stray 2.4 GHz signals whick keep knocking off my satellite radio -- It's a wonder the park isn't filled with mutant squirrels or Man-Spiders or something.

    • Re:What about SAR? (Score:5, Informative)

      by ajlitt (19055) on Monday August 09 2004, @08:32PM (#9925774) Homepage
      Usually, but for most devices under the 2m wavelength mark (>150MHz or so, which these would probably be), human body absorbption drops quickly.
      Of course, this is moot when compared to the EMI that most industrial electrical equipment generates. Hundreds of 3-phase motors, giant transformers, and multi-kilowatt circuits make for a far stronger field at the low end of the spectrum than an army of small sub-watt range transmitters.
    • So far what evidence is there that computers save work. Sure some work has been replaced (eg. manual calculation), but it has been replaced with more complex work (typed report->3d bar graph spreadsheet etc). Nett labour has increased due to computers. Ditto paperless office: computers generate more paper than the paper based systems that they replace.

      Therefore I don't have high hopes for energy saving via a new energy saving system. I can see visions of technicians rushing around in gas-guzzling trucks

      • Sure some work has been replaced (eg. manual calculation), but it has been replaced with more complex work (typed report->3d bar graph spreadsheet etc).

        Try manually calculating something like a trigonometric table. Then tell us about how it's easier than Excel bar graphs.
    • Why not the best of both worlds - be constantly annoyed by the wireless whisper AND get cancer?

      From the article:
      >The network is self-healing, too, so that in case a forklift driver blocks your transmission, the network will automatically search for another route that maps around the forklift

      The network is self-healing, so if a forklift goes nuts and you hide behind a container, it will the network will automatically instruct the forklift to go around the container to search and destroy you.
    • Mod Parent up, please.

      I agree and I'll add this little tidbit of data: The motor needs to be wired anyway. The electricity has to get in there somehow. Why not standardize on a fiber connector and an ASIC powered off of a CT in the peckerhead?

      Geeze. It's not the cost of the wire, folks, It's the labor you spend pulling it.

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