Meteohub questions

Hardware Weather Station Equipment
1

Hi folks, thought it best to start my own thread opposed to hijacking someone elses

Im just about to buy the NSLU2 but i have a few questions 1st

1). I have a 2gb stick and i ran the test program and it says no errors, I take this stick
is ok to run with the setup?

Test finished without errors. You can now delete the test files *.h2w or verify them again. Writing speed: 6.62 MByte/s Reading speed: 16.6 MByte/s H2testw v1.4

2). My stick has 2 partitions on it, one is for the security program and the other is the main
partition of 2gb, because of the 2 partitions this stick will not work in my car stereo because
it will only see the 1st tiny partition and not the main one, on the NSLU2 can you choose
which partition to use or will it auto detect the correct one?

3a). Can you use it with a wireless network (wireless USB stick)?

3b). Theres 2 USB slots on the hub can you use a USB hub to add more ports?
(Only needed if 3a above works)
4). How does it update the website? At present i am using the WD clientraw, testtags and trends-inc
to do this, would i need to modify my site to accept a whole new data upload system?

5). Could someone explain this in a bit more detail please, i.e. how would this below work?

WD ‘talks’ to MH across the network, so in theory at least (i.e. provided there is a decent network connection) the NSLU2/Meteohub could be in the house with your console and WD could be on the server in your shed. Smile
My NSLU2 is up in the loft.

I think that will do for now, sorry, but its a fair bit of money to just dive in feet 1st like i normally do :oops:

2

I dont have one myself (considering it though, saves a PC on 24/7). I believe what meteohub does is store all the weather data on a stick from which the software also runs, then when you turn your pc on you can tell WD to listen to the M-H and download all the data.
Not sure about plugging other things into the usb ports though, i guess that depends on the support of the core linux OS on it. You could always buy a NSLU2, flash the new kernel onto it then put the console version of WD on it. You may find this site useful http://www.nslu2-linux.org/ it explains everything about doing various things with the slug.

Im also considering buying an ARM procesosr kit and making my own unit (i much prefer to do things myself :wink: )

3

Don’t forget that production of the NSLU2 is officially discontinued (unless it’s been reprieved, but I haven’t heard anything to suggest that). There are probably still some around in the distribution channels but don’t be surprised if they’re not easy to find.

4

First up, the best place to ask any MH related question is the MH forum.
Here on Weather-Watch a few people here have MH/NSLU2.
Over on the MH forum all the active users have one, so there’s a whole lot more experience available.

‘Probably’ :slight_smile:
But see below.

MH requires the whole of the stick (the installation process involves copying in a fixed size disk image). There are people on the MH forum who could give a better answer about the implications of that for your stick than I can.

I’ve no experience of using with wireless. Best to ask on the MH forum.

I think that some people have used a USB hub. I have a feeling that it’s possible but not highly recommended. Again best to ask on the MH forum.

It does FTP uploads of things you specify. Those things can include:
Graphs: You set up definitions for the graphs, which then get generated and uploaded at intervals you specify.
Html: You can set up templates to include certain data.
Clientraw: Output of WDL clientraw files is under development. It works, but is not yet perfect. i.e. The main fields are populated correctly, but some things are not yet supported, or require extra work.

MH will not on its own replace your WD. It is more than just a data logger, but the NSLU2 is a very low power computer so there is a limit to what it can provide. WD running on a full blown PC does a lot of extra processing of data before it is able to generate some of the values in testtags and trends-inc.

If you visit the MH forum there is a section with links to MH driven websites. Some are very fancy. Some are quite simple.

The maximum frequency of upload is once a minute. I think that most people use a lower frequency. Remember that the NSLU2 is not a very powerful computer. I upload some files every 15 minutes, and one file (the one used by the Scottish & UK weather networks) every 5 minutes.

For the MH side there is a really excellent PDF manual. :smiley:
For the ‘talking to WD’ side there is an FAQ here on Weather-Watch:
http://discourse.weather-watch.com/t/33441

Wise move to ask questions. :slight_smile:
I hope you don’t mind the general theme of my answers, i.e. there is probably a better place to ask…

5

People still seem to be finding them. The alternative being to wait a few months. Boris is working on adapting MH for an alternative platform. The NSLU2 will continue to be supported.

PS. Before someone (Bashy? :lol:) asks, no, I don’t know exact details of the new platform. It has been chosen, but Boris is keeping that choice under wraps till he’s ready. The seems like a sensible decision to me. For more about the new platform see the MH Forum (do you start to see a theme in my answers on this topic :wink:).

6

Just edited my first post above to mention the FAQ here on Weather-Watch about how to set up communication between MH and WD:
http://discourse.weather-watch.com/t/33441

7

Thanks again, youve been a great help, I was a little reluctant to joining another forum if
i wasnt going to go ahead with this, but having said that, it looks like i will be i think it now
might be best to wait to see what Boris brings out in the next few months…

I also think i would be using it more as a backup to WD, i.e. if WD goes down for any reason
whether it be WD or the PC then the meteohub will still keep going and record the data, the
reason for “just a backup” is because i will still need to leave the PC on for the webcam stuff

8

The information that is already available about the new platform can be found here:
http://www.meteohub.de/joomla/index.php?option=com_fireboard&Itemid=32&func=view&id=1256&catid=2
You might notice that whilst more powerful the new alternative is also expected to be more expensive than an NSLU2. So the extra time may well be useful for allowing you to stuff some extra pennies into the piggy bank. :slight_smile:

Oh, and I don’t suggest getting too carried away by the mention of “will be able to support up to 2 usb web cams”. I gather you do some very heavy video processing so remember that this will still be a relatively low power (and Linux based) computer, so (just guessing) even if your web cams were connected to the device you’d probably still want a Windows PC somewhere in the system to do the extra ‘pre-production’ processing of the captured images…

I’m sure that is the best attitude for your situation, and probably for many others too, especially with the low power NSLU2 based version, i.e. treat it first and foremost as a data logger that also happens to be capable of a certain amount of independent data upload - with a PC running WD as the ‘front line’ system with the fancy footwork. :slight_smile:

PS. Probably obvious but your converted temp sensors that get processed by WD into solar readings and rain detection would simply be seen by MH as temperature sensors producing temperature readings (but if MH was connected to WD, WD should still be able to do its magic on those readings).

9

What I’m genuinely not sure about is the place of these very low power devices such as NSLU2 in the context of handling weather data as PC technology continues to develop. As has been said, these devices have pretty limited processing power and so you’re always going to need some further downstream processing eg on a server or other PC to generate complex web pages, do more detailed analysis etc. (Unless all you want is say a WDL presentation and the role of the low power device is simply to generate and upload the clientraw file(s), which is fine but is quite limiting in terms of not being able to do other things with the data.)

The so-called Small Cheap Computers (SCC) like the Asus Eee are continuing to be announced almost daily it seems and these aren’t only laptops. There are desktop versions (eg the Eee Box and MSI Wind PC), without their own display etc, and just in a small box - see for example:

http://www.clove.co.uk/viewProduct.aspx?product=825D7185-727C-49B9-A431-D06FEB1B735C

(I think these are not actually shipping yet in the UK but are expected to in the next week or two.) These are very compact units that consume no more than about 20W even under load, come in models preloaded with Windows XP and with adequately powerful Atom CPUs. OK these give only a proportion of the processing power of say a Core2Duo CPU but can nonetheless handle a moderately heavy computing load. I would have guessed that WD would run reasonably well on one of these. Launch price on these items is

10

Not to put you in a difficult position, but are you including weatherlinkIP in the category of things you are unsure about? Meteohub has way more possibilities for less $, maybe they just address different markets?

11

Niko, I think you’re right - they just address different markets.

For someone who wants the simplest, easiest way of getting their weather data on to an automatically-updating web page and doesn’t mind it being in a generic non-customisable presentation and is content with minute-by-minute rather than second-by-second updates then WLIP has got to be the winner (for VP/VP2 customers only of course, which is another obvious limitation). For many customers (who extend far beyond the hobbyist sector which I suspect dominates here) this is a perfectly acceptable solution. But if you want more flexibility or to pay a bit less then the MH route might be more attractive.

If Davis were to price WLIP as less of a premium product and were to substantially extend the feature-set and flexibility of the web-page presentation (which I’m sure they’re working on but I’ve no idea to what timetable - there are some features that are late already despite some busy programmers) then it might be more of a close contest even for prospective MH/VP2 users.

12

Fine by me. Interesting thoughts.

As is often the case in IT, a better solution may be available shortly… :wink: :lol:
… but if you are ever going to get anything done, at some point you need to go with what is actually available.

I find MH/NSLU2 a very usefull tool - and have been doing so for the best part of 6 months (and hope it has a lot of life in it yet). I have no problem with it needing a bit of extra help for additional and more detailed (and usually longer term) analysis. Your Mileage May Vary.

13

John, what’s your guess of the % of VP’s that are connected to computers?

14

I can only really talk about the ones we sell because that’s all that I’ve direct experience of. Different dealers maybe handle distinct market sectors and see a somewhat different picture. But the figure from where I’m sitting would be that 90-95% are sold with loggers and I’ve no reason to doubt that the vast majority of the loggers are used - maybe not connected up on Day 1 (although a lot are), but shortly thereafter.

15

Wow, I didn’t expect that 8O

16

I’d say that’s fair comment on the second-generation Atom PCs, but the first generation are essentially here now. The original post was maybe rather UK-centric, but if I was in the US then the EeeBox is shipping now AFAICS for $339 - see eg:

http://www.newegg.com/Product/ProductList.aspx?Submit=ENE&DEPA=0&Description=eeebox&x=0&y=0

(It may conceivably be cheaper elsewhere.) So if I was in the US and wondering whether to get an MH or not then something like the EeeBox to run WD on directly would be a real option here and now.

Don’t misunderstand me - I’m not seeking to knock devices like NSLU2 at all - in fact I’ve got one here. But I’m genuinely trying to look into the near future and understand what it is about NSLU2-type units that might tempt users down that road rather than eg running WD directly on an EeeBox, which on the surface seems a comprehensive, low-power solution for not too much more cash than son-of-NSLU2 might cost.

I guess one possible answer is that we don’t yet know how fast WD might run on an first-generation Atom-based PC, how many features (webcam etc) it might be possible to run simultaneously and so on. I suspect it would be fine, but it’s only a guess. Presumably no-one’s developed any sort of rough WD benchmark for assessing how well WD runs on different specs of PC, ie a sort of WDMark?

17

It was intended as a slightly tongue in cheek generic comment (i.e. it’s been applicable for years, and seems likely to remain that way for a while yet). Hence the smileys.

No offence taken. I really do think your comments are interesting - and valid.

PS. I’ve had an Asus eeePc 701 since last December when they first came out. Even that “pre-Atom” device is a really great tool. :wink:

18

Just out of interest how to commercial remote stations log there data?? They must have some pretty low power cpu’s to log the data using solar?

19

An afterthought…

People who don’t have a VP and thus don’t have the ‘buffer’ of a datalogger between their Wx and the WD PC might well be looking for an equivalent, i.e. the extra security of an intermediate store.
If that intermediate store can do other stuff too maybe that is just icing on the cake to such a user?

20

I think that there are different scenarios depending on what the remote station is called on to do.

Actually logging the data at the remote site doesn’t take much power, either electrical or CPU power. Something like the VP/VP2 systems manage this all within the same power budget as the console itself and so eg a wireless VP2 can run for 6 months or so on internal batteries alone or indefinitely on a pretty modest solar panel. If the system doesn’t have a system/built-in logger but uses an external logger then again these can - depending on model - run for long periods on small, simple internal batteries. (Actually I think that quite a proportion of ‘commercial’ loggers are still relatively old-fashioned in having analogue sensors that are wired to simple but high-quality A/D converters in the logger and again this seems to be an architecture that really isn’t very power hungry.)

But all such loggers require someone to visit the site to download data to a PC.

If you want regular and automatic uploading of the data to a central office or server then that immediately becomes much more of a challenge in terms of the electrical power budget, which tends to dominate the design more than CPU power. Again, it’s much less the logging than the data communications mechanism that needs the power. So even a basic telephone landline modem consumes a significant amount of power and I suspect that this typically becomes the main factor in sizing the power supply for a remote AWS. And if you want to use say a GSM/GPRS modem then the power demand can increase further. You need a surprisingly large solar panel and high capacity, deep cycle batteries (= expensive) to provide fully reliable year-round data uploads in places like the UK with its fairly northerly latitude and frequently cloudy weather. Of course this may be acceptable for the more sophisticated commerical/official remote AWS sites where the instrumentation cost alone may already be