Ethernet connectivity « Jee Labs Talk

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Ethernet connectivity

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olliver

Hi!

I'm new here. Eagerly waiting the first JeeNodes to arrive (Thanks JC!). But, in the project I have in my mind, I'm planning to use ethernet for data transfer at some point (I've wiring ready in my house). That is, I'm planning to collect data from JeeNodes here and there to some 'hub node' and from the 'hub' to my server thru wire.

For this hub node I've two alternatives (I like it to be simple). First, I could attach an ethernet module, for example http://www.saelig.com/product/ETH042.htm, to JeeNode. This Wiznet module is running at 3.3V and interfaces with SPI. The nice thing is that the module has TCP/IP stack embedded, so it does not require huge loads of new software. Should be easy?

The second alternative would be to add HopeRF radio to an ethernet enabled board. Maybe Arduino with an ethershield extended with a HopeRF module? I also considered tuxgrapchic's device (http://shop.tuxgraphics.org/electronic/detailavrwebserversmd4.html) but I'm a bit worried does it have enough resources.

Now, what do you think which route should I take? As I said, this 'hub' does not have to be anyhow sophisticated, so Linux systems seem to me a little bit overkill.

Software is no problem for me, but fitting hardware pieces together might be. I did my electronics courses, but lack the practice.

Posted 17/11/2009 21:31:33
jcw

The Wiznet sounds like an interesting / low-cost option.

It all depends a bit on how much processing you want to do and where the "smarts" need to be. In my case, I'm interested in running at rock-bottom power consumption levels - so I want the hub to do everything at once: ethernet & JeeNode interfaces as well as being a reasonably complete web- and automation-server.

A small embedded Linux board need not be expensive at all - I've been experimenting with the Propox MMnet1001 as described on the weblog, see http://news.jeelabs.org/2009/03/12/jeehub-prototype-2/ and http://news.jeelabs.org/?s=mmnet1001

Another interesting option was suggested in this forum a while ago: http://talk.jeelabs.net/topic/44

If all you want is to collect all data on your PC, even when the PC is off, then a JeeLink v2 is actually enough: it has flash memory on-board to collect data in unattended mode, which can then be read out when the PC comes back on. There will be a post on the weblog about this, soon.

But yes, for remote access at all times, and for permanent home-control uses, you need [i]some[/i] server [i]somewhere[/i].

Posted 18/11/2009 15:04:31
olliver

Yes, you made me realize that I actually have to play with the existing stuff first before planning further. JeeLink is indeed a nice concept and it may be enough. But I have a server running anyway, so routing stuff there via ethernet is convenient. And I'm not sure what is the effective range of these RF modules indoors with concrete walls etc. But, as said, have to experiment.

Posted 18/11/2009 23:04:27
warwick

I'm no expert, but wouldn't a SPI attached Ethernet board (for example the 'official' Arduino one uses only pins 1-13), attached to an already power efficient Jeenode be almost 'zero power' if you assume that the smart stuff (logging, graphing etc) is run on a remote (maybe shared, virtualised) web server that is already running 24/7 in any case.

This would also reduce the cost and complexity of the main board at the 'house hub' - indeed there could even be another 'new' Jee board design that was radio+arduino+ethernet. The additional cost of the magjack connector and wiznet spi ethernet chip is well under 10 euro, even as a one off.

Its beyond my skills to design or make such a board (yet!) but I'm sure it would simplify things for some implementations.

Just my 5p worth, as we say in (cold, energy inefficient right now) England.

Posted 14/12/2009 17:37:12
jcw

I think we're saying almost the same thing - the "remote" server merely being placed locally inside the house in the scenario I alluded to. Is the central unit part of the web - or is it part of the house? I suspect there are good arguments to be made either way. Which, probably also means it'd be best to support both options, at some point.

It's basically a choice of at what level to step over into the ethernet/internet boundary, with TCP/IP, web servers, etc. If both units are local, then a direct serial/i2c/whatever link between server and JeeNode is possible, if the server is internet based, then yes - there will have to be some way to go from JL to ethernet.

Posted 14/12/2009 18:52:25
warwick

On the assumption the server needs to do things like produce graphs, possibly send SMS, email reports etc its probably a 'real' pc in most peoples homes, rather than a hackable repurposed NAS drive or similar. Worst still it's likely to be an old one for costs sake, but less energy efficient (have you looked at how appallingly inefficient a 5 year old cheap ATX switched mode PSU is?). I guess what I'm saying is my angle of 'server on the interweb' posibly saves as much as 200W of electric on a machine switched on 24/7/365 - thats 1.75 Mega Watt Hours a year, or around £192 / 220 euro of energy a year - or 850kg of CO2 if you prefer!

Without being too evangelistic, my view is 100% put the hard work in an efficient datacentre running efficient machines (both modern and load balanced and virtualised). If you are a hardcore greeny (nothing wrong with that!) you could even choose a carbon neutral datacentre that uses green electricity and uses the waste heat to warm local old people!

Posted 14/12/2009 23:41:04
jreitz

FWIW, I'm working on an ethernet JeeNode "board". In fact I've finished my first design and I should get it back from the PCB fab house in a week or so. I'm not using Wiz chip because the interface looked a bit jenky (of questionable quality, as we say in California) and also I wanted a bit more of a challenge. So I'm using a different chip.

My initial goal is to pass RF messages back and forth from a known IP via UDP. I believe I can support TCP/IP in the future and I'm planning on adding some implementation of transport layer security, probably via AES. My target use case is as a gateway for remote arrays of JeeNodes, in places where one would not need a full server and as a quick way to add RF coverage to a large office which is already wired. Perhaps Seaton's widget-mesh would be a better solution for this though.

But I agree with J-C in that most people will be better served by a JeeLink plugged into their NAS, Bifferboard or DD-WRT access-point. We'll see when this gets done though, as I have work and a 4-month old baby and I'm used to writing code 5 layers further up the stack. This stuff is fun though.

Posted 26/12/2009 01:17:37
jcw

That's great news! Is this a piggy-back board for the SPI/ISP header? Are you using the ENC28J60 board? I'd love to help out on the software side. Yes, having a low-end option as well as a Bifferboard-or-other-Linux as high-end option would offer the most flexibility.

Looking forward to your progress!

Posted 26/12/2009 15:41:23
jreitz

Yes it is a piggy back board for the SPI header although it physically interfaces with the whole JeeNode (lays flat). The current version uses SPI but I'm working on a fork which uses a parallel interface and thus will need all the plug pins as well.

I'm using the ENC424J600 chip because it has much larger buffers which are a must for TCP/IP given our RAM constrained host processor and it has an on-chip crypto engine. And the parallel interface looks like fun to play with.

I'll post updates when I get the boards back. I'm sure I've screwed something up with them though.

Posted 26/12/2009 20:58:59
dkb

I would also be interested in ethernet connectivity so that the JeeNode data could be sent to a REMOTE server. In my case the internet service provider charges extra for a routable IP so my website is hosted at a commercial data center. I currently use a WIZnet board and Duemilanova. I would like to note though that the WIZnet chips have been known to run exceptionally hot so I question their reliability long term.

Posted 28/12/2009 16:29:33