Cumulus & OS LW301

[cancunia]

I think this subject has been touched on in a couple of other threads, but wanted to ask again about possibilities.

Over the past few days I've been looking for an alternative to the OS Anywhere Weather site. It seems to work in a basic kind of way but is nowhere near the maturity of Cumulus. Since the LW301 connects via USB to an Internet hub / bridge, I wondered how different the protocol it uses from any of the other OS stations and then of course if it's possible to get it working via Cumulus? I'm happy to do any testing, but have no clues where to start. Plugging the LW301 into the USB port, simply gives an 'unknown device' error.

Thanks

[steve]

I don't think it has any protocol at all for extracting data from it. If it had such a protocol, it would presumably be supplied with software (like Easyweather) to extract the data to a PC.

[cancunia]

It must send data in a pre-determined format? Is it that the other stations can be queried, rather than the application just listening to a stream? Sorry if I'm not making sense, I don't understand how these things actually function.

There is some software from a project hosted on Google code which runs on Linux and claims to support the LW301, but I'm not knowledgeable enough to understand how to make it work, or how it works with the LW301. Maybe it's time for a bit of Debian work on my part.

https://code.google.com/p/wmr/wiki/WMRSupportHardware

[steve]

The way the WMR100 etc work is that the PC sends a command and the station starts transmitting data packets; the PC has to acknowledge each one so that the station continues sending packets. My understanding of the way the LW301 works is that it can only send its data to a web site. So I guess it would be possible to either scrape the web site for the data, or pretend to be a web site and receive the data that way. I would guess that the 'protocol' is very different to the USB-based protocol of the WMR stations.

[steve]

I had a quick look at the source code for that software, and I couldn't find anything specific to the LWS301. So if the software really does work with that station, perhaps it does use the same protocol as one of the WMR stations. I think I misunderstood what you were suggesting, which was to bypass the main box of the station and plug the receiver into a PC, so getting at the data before the main box had received it and uploaded to the web?

One thing that puzzles me about that wmr software is that I can see where they are interpreting the WMR100 packets, but not the WMR200 packets, which are completely different. It says it was tested on a WMRS200, which slightly confusingly uses the WMR100 protocol. So perhaps they are making claims to support hardware which the software doesn't actually work with.

[cancunia]

Correct, the idea is to bypass the 'bridge' or 'hub' as OS call it and plug the 'receiver' via it's usb cable into a PC. It's almost certain that the hub does some processing of the receiver data before uploading it, but exactly how much is what's interesting. One thing seems certain, there will need to be something that manages the USB port, are there any drivers associated with the OS boxes?
It does seem odd that the code makes no distinction between the devices and the project may just be making some broad assumptions, but there's a hint here about 'data logging mode' that I'll follow up on - http://www.bashewa.com/wmr200-protocol.php

I think the code was based on a much lighter program called wmr100 which I'm attempting to get working, looks like I'll need to build a Debian box to get all of the libraries to behave.

[steve]

One thing seems certain, there will need to be something that manages the USB port, are there any drivers associated with the OS boxes?

No, they appear as 'HID' devices, so don't need any additional drivers.

[cancunia]

Well, that's one clear difference. I'll follow up on the Linux side and report back if I come across anything positive.

[ZEbbEDY]

Would be amazing if the lw301 would work with cumulus, how does the Linux wmr work with the station does it allow you to view data locally without being connected to the internet from your Linux PC?

[steve]

how does the Linux wmr work with the station does it allow you to view data locally without being connected to the internet from your Linux PC?

Evidence suggests that the wmr software does not actually work with the LW301. I would be happy to be proven wrong, though.

[cancunia]

From what I've seen so far, the LW301 does not really behave like a USB device even though it uses a USB lead and connects to ports labelled as USB, about all it does do on a usb port is to power up. Maybe a device driver can be written or already exists. I've asked around and am waiting for some replies, in the mean time I'm looking into capturing the data that comes out of the hub which is in HTTP post format.

[JohnGB]

I've been doing a bit of investigation into the data stream sent from the receiver to the hub and it appears to be standard serial. Data rate is 9600 baud, 8 data bits, No Parity, 1 Stop Bit, the signal levels are about 2 volts so would probably need some level conversion to work with normal serial ports/interfaces. Connecting directly to the in-built serial port on the Raspberry Pi GPIO pins seem to work fine.

I'm still in the process of fully decoding what all the Bytes/Nibbles mean, but they aren't too far off the existing message formats as described here: http://wmrx00.sourceforge.net/Arduino/O ... tocols.pdf

I'll re-post here as I progress further if that will help.


John

[cancunia]

John,

Thanks for posting this info, it probably also explains why I could not see any activity on the usb ports on my Pi, although inexperience probably also played a part. I would certainly be interested in hearing about progress and will check out your link.
It is a shame that the LW301 has been released in such a half baked way.

[didierheck]

Hi Guys,

This thread is looking very promising !
What are the latest news ?
Can we finally use the LW301 directly connected to a RaspberryPi ?

DDA

[JohnGB]

I supplied a copy of the protocol decoding that I carried out to 'cancunia' but I haven't done any work on it for some time now.

The problem for me was that the hardware didn't seem particularly reliable, particularly the wireless side of it. The various sensors would just stop sending data for some reason. Sometimes a reset of the Hub would suffice to get things going again, but more often that not it required a reset of the sensors themselves. I also found that the external Temp/Humidity sensor in particular went through a set of batteries every 5/6 weeks.

I dismantled my set-up and it is now languishing in a box in the loft.

All in all, a rather disappointing outcome. If the hardware had been more reliable I would have persevered and written some code to get it working on the RPi.

Sorry I'm not the bearer of better news.

John