Zigbee

:)

From the looks on the faces of some of the actors in the commercial I wouldn't be surprised.

Robert

Reply to
R Adsett
Loading thread data ...

Wrong question. The first question is not why network to co-ordinate time but why does it have a time of day clock to begin with? I long ago stopped setting the clock on my microwave for instance, I have absolutely no desire to use it for a clock I just want it to warm my food. My kitchen clock is a far better clock than my microwave ever will be.

Feeping Creatures!

Robert

Reply to
R Adsett

Fair enough. However, the VCR, and the kinds of coffee makers that can automatically make my coffee so that it's ready when I wake up in the morning both have a genuine need for time of day.

Also, as an extension to your argument, you could say that if all members of the household have reasonably accurate wristwatches, then all clock displays are unnecessary.

Ed

Reply to
Ed Beroset

Yes, those are all alternate methods of deriving the time of day, but are they all cheaper to implement than, say, a local area power-line carrier network? Remember, only one device actually needs to get the time independently, perhaps from one of the sources you mentioned. The others could get it from the device which has the most accurate time. I don't need a TV receiver, a digital radio, or a GPS receiver in my coffee machine.

"Too costly" and "bloated" both presume some particular implementation (and a bad one at that). I'm not advocating any particular implementation; I'm simply pointing out that there *is* a potential benefit to connecting appliances -- in your original post you seemed to believe that the only reason to connect devices was "because we can."

Sure, that sounds like the old IRIG-B standard. This would meet my definition of connecting appliances to meet this one particular purpose, but do you think it's reasonable to use for connecting appliances?

Was the gratuitous demeaning comment really necessary?

Ed

Reply to
Ed Beroset

I wasn't advocating any particular implementation -- just pointing out why one might want to connect appliances.

This is a good point. I suspect my microwave oven aleady has such approval.

I have such a clock on my desk, but it's not connected to any other appliance or device and I notice, for example, that my PC's clock is about two minutes slow. Is there a chipset which implements, say, a WWVB or GPS receiver inexpensively? Atmel's Zigbee chipset is priced at US$6.75 (in 100k quantities) according to an article earlier this year. That's a lot of money to put into a low-end appliance, but could perhaps be absorbed into the cost of a high-end model which "special features." What's in that range or cheaper?

Ed

Reply to
Ed Beroset

The VCR and coffe maker I'd accept, although I'd question how many people actually use that feature in either one. The trouble with clocks on all and sundry devices is the tryanny of timekeeping. We feel compelled to set them, guilty if we don't set them and feel as if we should track every tick and tock as we are continually remided of the relentless count of time.

Yep, although I'd turn that around, clocks are so all-pervasive and invasive that I havn't worn a wristwatch in some time. If I need to know the time it's already available easily elsewhere (PC, Cell, public clock most of which appear to reference a more accurate reference source (I know my PC does)). If it's not readily available all I usually need to know is that's it's say mid-afternoon and that is quite readily apparent w/o any clock keeping technology.

Robert

Reply to
R Adsett

Well, we're back to what I said in my article then - which is that the current protocols are ridiculously complicated because they are attempting to be all things to all people; they solve problems that don't exist.

For example, I'm not aware of any such protocol that includes both unidirectional and bidirectional appliances.

And as I asserted in my article, the bread-and-butter appliances that manufacturers are trying to sex up are extremely price-sensitive. They are commodities. The market for "high-end" versions

Remember that the Zigbee chipset is only a small part of the BOM cost! The cost of an entire RF receiver circuit that can decode the atomic clock signal is roughly $3.50 plus a capture/compare input on the appliance's microcontroller. That's the entire circuit cost.

To that $6.75 chip you need to add passives, antenna and board space.

Reply to
Lewin A.R.W. Edwards

Largely that's true. They start out solving something specific and then morph as people get big ideas to tack on. I've seen this, too. However, you understand that there is a tradeoff in specificity versus generality. If it's too specific, then chip makers won't be bother to make them, and if it's too general, then it gets just the criticism you level at UPnP. I don't say it's unwarranted, either, but that it's not

*just* explained by that frightening phrase, "designed by committee."

I know of proprietary protocols which offer that, but they're extremely application specific.

Your sentence was left incomplete, but I'm imagining you might have said, "The market for 'high-end' versions is not that large and the companies that participate in that niche usually make the bulk of their sales (and profits) at the lower end of the pricing spectrum." Since I've put the words in your mouth, you won't be surprised to hear that I agree!

However, as a counterexample, lately I've seen car stereos with a remote control. My car's not big enough that I could get out of arm's reach of the stereo and still be inside, so it seems odd to me, but *somebody* is buying these things, and paying the additional money required to pay for the remote control, additional batteries (they're included on the models I examined) and the design effort to put in an IR receiver port on the fixed-size and already extremely crowded faceplate.

OK, but the same is true for the proposed alternatives. Compare that to the cost of a GPS receiver to extract the time and date (the original problem) or a RDS receiver or a TV receiver and associated decoding logic. Do you think you could come up with cheaper than $10?

Ed

Reply to
Ed Beroset

Main reason that I wear a watch, these days, is to be reminded of the day and the date. They're much harder to discern by looking at the sky. :-)

Cheers,

--
Andrew
Reply to
Andrew Reilly

In data 30 Nov 2004 19:13:07 -0800, Lewin A.R.W. Edwards ha scritto:

Hi friends, thank you very much for your answers and thoughs.

So ZB could not be the right choice for a LPDR solution since it is not an open standard.

What about IEEE 1451.5? It is an ongoing job of IEEE about wireless sensor networks. Their aim is to produce a common protocol that let sensors of different vendors cooperate in the same environment.

I think it could be very usefull in order to maximize the investment for a wireless sensors network.

What do you think about it??

Saro

Reply to
Sarouiki

Vendors of wireless sensors have very good reasons, and take considerable efforts, to exclude third party products from connecting to their networks. I do this in my day job. Partly it is a profits issue, of course, but there are also terrible support and liability problems when third-party products are allowed into the mix.

If you're looking for a universal standard that is ACTUALLY going to be implemented by other people, please don't hold your breath.

Reply to
Lewin A.R.W. Edwards

You're talking here specifically about a very broad-base kind of application - broadcasting a time signal for all appliances in the house to digest. A credible home networking standard should account for the fact that some data is going to be sourced in a few places and sunk in a lot of places, and furthermore that some appliances will never have, or for cost reasons will not be able to have, good reasons to communicate; they will be pure data sinks that merely need to understand their environment without interacting with it bidirectionally.

The hand is faster than the eye :) But I basically agree with what you say anyway.

HOWEVER! A car stereo is a special case, because it is scientifically proved that a man's genital size is directly related to his vehicle's capabilities, accessories and racing stripes. You can sell practically anything into the automotive aftermarket, no matter how expensive or ludicrous.

I'm talking about bread and butter appliances like coffee makers and microwaves. There IS a market for custom luxurious devices of this sort, but it's exceedingly small; I would say, not worth exploiting. And the people who currently sell almost all the volume in this sector are bulk shippers of Asian-made kitchen electronics. They do not have the sexy high-end vibe that consumers of the luxury devices would require.

GPS? My $3.50 BOM cost is for receiver IC, all required passives, and antenna, to receive that atomic clock off-air time signal. That's for volumes that are somewhat smaller than microwave shipments. I've assumed the product already contains a reasonably fast 8-bit micro (which is a ~$1.10 cost in the same volumes, just in case the microwave doesn't already have a fast enough brain).

The $6.75 Zigbee chip price you quoted requires probably another $3 in passives and antennas.

Yep. Do it every day at my day job, in fact, though in a much higher frequency band. Actually, I can get a low-data-rate transceiver put together for less than that, if you don't count the cost of the micro. But I wouldn't ADD $10 to the cost of a $10 appliance by squeezing this crap into it.

Reply to
Lewin A.R.W. Edwards

...

You are forgetting a few things, but see more general comments on the end as well.

a) Most countries don't like data over power WITHOUT suitable blocking filters to stop your data interfering the power companies signalling and next door neighbours signalling etc..

b) The coffee maker does not require accurate time keeping see later.

c) Adding a connector (or power line data receiver) to a VERY cheap device adds cost, also adds cost to the documentation, testing validation to necesary standards etc..

d) For a coffee maker it is overkill and unecessary where as time synchronisation is important for timer functions related to the outside world (i.e. VCR), so they use the time components in that medium to reduce cost.

e) A distributed time signal as others have stated is a solution looking for a problem. The real time saver would not be setting of time by network but a simple means of daylight/standard time switchover. Even then that is a luxury market item as so many timers are in different markets (heating systems, clocks, appliances).

f) making the potential for ALL users NOT to foul up the wiring of time network when cross connecting between ANY manufacturer at ANY distance around the home, is not simple. The cable will always be too short, too long or wrong connector or wrong protocol!

The cost of putting an atomic clock receiver into EACH device that has NO other means of receiveing time (i.e. VCR) would be cheaper than power line carrier network.

To manufacturers of microwaves/coffee machines just adding another connector or power line receiver is bloated. To sort out support issues of what to do if that time network does not exist, or a different time network exists, cabling and associated issues adds to the product cost.

It is "because we can", which is at the end.

No only for SPECIAL circumstances that require it and the home does not!

It was on reflection over harsh, but you were trying to get a solution before determining the problem.

Let me put timekeeping in the house in perspective.

If you ask some one the time, what will they tell you? Most likely the time to within 5 or 15 minute intervals, e.g. "five [minutes] to six", "quarter past three". This is one of the reasons that people created even TV listsings to that level of accuracy, for the public. Inside a broadcaster the TV schedule may well be done to the second for adverts/trailers, programme elements or the like.

Now we know the general public runs its life realistically to time in steps of

5 minutes.

Also if you were to wander around a house and look at all the timing devices (clocks to heatings systems), you will find it most unlikely that any two were showing the same time to same minute, some may well be run deliberately ahead or deliberately behind 'real time' measurement. For example the alarm clock set 10 or 15 minutes ahead of time, so soemone will get up, rather than leave things to the last possible moment to get up in the morning.

Does the public's life go awry because of this? No because they are not living their lives that rigidly, and are flexible.

Now consider the appliances they do NOT need to be synchronised to a time standard, they need to measure elapsed time accurately. By this I mean if you set your coffee maker to start at 6:25 AM, it does not matter if the time standard ('actual time') is 6:20 to 6:35, all that matters is that it is as near as possible 24 hours elapses between each time the coffee maker registers 6:25AM. Will you always be up and ready to take the first cup of coffee at exactly the same second (or even sub-second) every day? No of course not we all do things to slightly variable time each morning and things get in the way (longer in the bathroom etc..). As long as the vast majority of times this means the coffee is ready each morning before you enter the kitchen is all that matters, it may have been for 10 minutes but so what.

Things that need to be synchronised to a time standard can be, such as VCR so you record the programme at the time specified in the listing, which is when they transmit the programme. Other such items might be a telephone answering system (which can in UK get the time from the Caller ID data stream) so that both ends are refering to the same 'actual time' that a message was left.

The only possible problem that could do with a 'network' solution is the daylight/standard time changeover with the ever increasing number of timers in products. Most are getting so they do this themselves, VCRs from TV signals, phone systems from Caller ID strings, clocks from atomic clocks and the humble computer by software date calculations and interent time servers.

The real appliances that could with an automatic clock are heating systems as they often are the ones forgotten.

So networked appliances are generally not necessary and only will end up with a USB situation where more and more will be put in the serving end, so if the serving end fails ALL the other appliances will stop working! Why because they can then make the 'client' end cheaper, so foregoing the timer function but using the time signal to measure time. Then when your server fails your microwave cannot time how long to cook and coffee filter does not come on at the specified time, the VCR fails to record the programme you want.

--
Paul Carpenter          | paul@pcserviceselectronics.co.uk
    PC Services
 Click to see the full signature
Reply to
Paul Carpenter

In data Sun, 05 Dec 2004 13:42:47 GMT, Lewin A.R.W. Edwards ha scritto:

And, what about 802.15.4 without ZigBee? Do you think it could be a good solution for the physical and MAC layers?

Saro

Reply to
Sarouiki

I would take that one step further. Use one of the cheap 802.15.4 transceivers for the physical layer but not the MAC. The standard for the MAC is like 600 pages long. Implementations are, in general, not free. You can build simple MACs on top of the physical layer with little effort.

Reply to
Thomas Carley

If my coffee maker had a "back button" so I wouldn't have to press the "up button" 23 times every fall, I would gladly pay the extra cost (up to $0.10 US).

I may be kind of a funny old fart engineer, but I am surrounded by electronic devices that could be vastly improved with a little better engineering and a little bit smarter software. A network might be cool too, but first choice would be the extra button.

-Hershel Roberson

Reply to
Hershel Roberson

Well thought out control panels are getting rarer in my experience. Too many multi-level menus, often for options not on this model.

--
Paul Carpenter          | paul@pcserviceselectronics.co.uk
    PC Services
 Click to see the full signature
Reply to
Paul Carpenter

Maybe I'm just extraordinarily lazy, Hershel, (and there is some evidence for this!) but I'd rather have a no-button interface that didn't require me to fiddle with it at all. A Model T Ford used to have a spark advance knob. I don't think that the loss of it was widely mourned.

That's because a hundred lines of code is cheaper than the $0.10 button, and if everything is software you don't have to think things out because "you can always patch it later."

Ed

Reply to
Ed Beroset

I wholeheartedly agree that the necessity to purchase a software stack will be a handful of nails in zigbees coffin. Zigbee cannot survive (or rather, flourish) under this weight.

A shame really, Zigbee stands to do so much more than UPnP by simply filling a far more necessary whole (the interconnect).

Myren

Reply to
myren, lord

Necessary, no, but I can see many possible uses for networking appliances and other electronic/electric devices in my home.

  1. Fault detection - I'd like to know my deep freeze in the basement stopped working the minute it stopped, not a day later when all my stuff thawed out. I'd like to know if my dryer was running too hot, or water heater pressure was too high.
  2. Cycle completion notification - My laundry equipment is in the basement. A notification that the washer was finished to remind me to move the clothes to the dryer would be nice. Likewise, having my oven or microwave let me know when the cooking time was finished would be nice as well.
  3. Usage data - What shows were watched on the TV? What did my kids (if I had any) watch while I was gone shopping? Who called me last Tuesday and at what time, or who made that long distance call to Buenos Ares? When was my doorbell last pushed? How much electricity is my water heater/refridgerator/dryer/etc. using (so I can look a more efficient model)? What's my water usage for the month?
  4. User Interfaces - Some devices have cruddy built in user interfaces. How many people use their oven's programmable cooking features (for instance, for putting something it when you leave for work and having it done when you get home)? I'm not going to go to my PC to program my coffee maker, but I might do that for my oven. More practical would be my thermostat, to regulate my heating and cooling system according to my usage patterns. Typical programmable thermostats have horrid user interfaces. But a web server type interface could be a rich as needed.
  5. Others - Rainfall for my area is up (or down) this week, so adjust my sprinkler system accordingly. The garage door has been open for ten minutes (oops, I forgot to close it).

None of this is necessary. Ice makers and water dispensers on a refridgerator aren't necessary either, but people will pay for the convenience of them.

Reply to
daworm

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.