433MHz to LAN gateway or miniserver?

A weather base station with a serial port and this

Over $100

Cheers

On a sunny day (Thu, 1 Apr 2010 23:05:06 -0400) it happened "Martin Riddle" wrote in :

It is easy to make, a PIC 18F67J60, a 430 MHz module, magnetics, some programming, maybe 10 $ in parts.

I would build it with modules. 433 MHz transceiver, 5 euro:

Ethernet module, 25 euro:

I thinks this would be sufficient for the LAN port side. The schematic for the ethernet module is free, so maybe you could create a better PCB for mass production with the RF module.

For the sensor boards you can use any cheap microcontroller, which has sufficient resources for your sensors and the RF module. And the RF module has already an integrated temperature sensor.

The software would be a nice project for a weekend :-)

--
Frank Buss, fb@frank-buss.de
http://www.frank-buss.de, http://www.it4-systems.de

There is a specification used by the likes of Jennic and others called

6LowPAN which allows IP addressing of radio nodes specifically to allow them to be accessed in ths way. There are also free 6LowPAN stacks on sourcefourge. Jennic certainly do 2.4GHz radio modules with this, and there may well now be some ISM modules with it.

The Holy Grail for me thouigh would be a very low power mesh network, such as DigiMesh, using something like 6LowPAN to connect it to a LAN.

Mark.

For just the port? That would be too much, and we'd still need a radio module. Ideal would be one that has the radio part in the box.

--
Regards, Joerg

http://www.analogconsultants.com/

"gmail" domain blocked because of excessive spam.
Use another domain or send PM.

programming,

Sure, we can make it, but that's what we wanted to avoid. Just the radio certs can become a pain in the neck. In most countries you must have a blessing from an EMC lab before marketing it.

--
Regards, Joerg

http://www.analogconsultants.com/

"gmail" domain blocked because of excessive spam.
Use another domain or send PM.

Thanks! Now I know the phrase for searching, LoWPAN.

--
Regards, Joerg

http://www.analogconsultants.com/

"gmail" domain blocked because of excessive spam.
Use another domain or send PM.

One challenge would be that it has to work standalone on the LAN, so it can be polled from the web even if no live computer is connected to this LAN other than a DSL or cable modem. It would have to act as its own little web server or at least auto-connect to a site on the web.

On the sensor board there's already a uC.

If this happens I'll tell the client to throw it over your fence. uC programming ain't my cup of tea ;-)

--
Regards, Joerg

http://www.analogconsultants.com/

"gmail" domain blocked because of excessive spam.
Use another domain or send PM.

Then maybe a bigger module would be a good idea:

This is all you need on the LAN side, and a connection to the RF module, which I assume has already all passed all the EMC requirements, so the final device should pass the EMC tests.

Thanks. I don't have much time, but if you do the hardware, it should be not too difficult, because the hard programming parts are already done, e.g. TCP/IP stack, web server and there are sample code for initializing and transfering data with the RF module. So I just need to write some error correction (there is already code for this part at

, if I want to do something challinging and using Hamming error correction for such a low bandwidth application) and a simple protocol with collision detection and maybe channel hopping for querying the sensors.

--
Frank Buss, fb@frank-buss.de
http://www.frank-buss.de, http://www.it4-systems.de

Thats on-route. When do you need it and in what quantities?

--
Failure does not prove something is impossible, failure simply
indicates you are not using the right tools...
nico@nctdevpuntnl (punt=.)
--------------------------------------------------------------

We're working on similar devices for domestic use. LoWPAN seems to be a pain in the ass to implement. We go for full IP including real security (thats whats missing in other products).

--
Failure does not prove something is impossible, failure simply
indicates you are not using the right tools...
nico@nctdevpuntnl (punt=.)
--------------------------------------------------------------

LoWPAN Seems to be a complicated protocol. This article:

says there is an implementation which needs a 32 bit microcontroller with

192 kB ROM and 96 kB RAM. Looks like the IEEE 802.15.4, which is the base standard for it, is not easy to implement. Same if you would use something like Bluetooth-Piconet.

If there is no interoperability requirement with other devices, would be much easier to implement a protocol just for the task at hand, e.g. a simple polling protocol with one master, which makes things even easier.

--
Frank Buss, fb@frank-buss.de
http://www.frank-buss.de, http://www.it4-systems.de

On a sunny day (Fri, 02 Apr 2010 07:41:00 -0700) it happened Joerg wrote in :

programming,

Those modules are certified. What else if no design? Try shopping unlimited.

This doesn't matter. If you are assembling multiple modules to a new device, you have to certify the whole device again (but chances are good, that it passes the tests without problems, if the components passed the test already).

--
Frank Buss, fb@frank-buss.de
http://www.frank-buss.de, http://www.it4-systems.de

On a sunny day (Fri, 2 Apr 2010 18:40:57 +0200) it happened Frank Buss wrote in :

Use 2 boxes. Boxes are cheap.

We don't need much security for the RF link, and only very low data rates. Even 300bd would be just fine but must be bidirectional.

Yikes. That sounds like Windows or MS-Office where you need at least a gigabyte of RAM to write "Hello World".

Looks like it :-(

It's strange, everyone is talking about ambient assisted living but it's all just PowerPoint jockeying and talk, no real action.

--
Regards, Joerg

http://www.analogconsultants.com/

"gmail" domain blocked because of excessive spam.
Use another domain or send PM.

Nice!

Well, this client definitely does not want to do any sort of EMC test. Has to be pre-certed and ready to go. Software writing and (very minor) asembly work would be ok, but not a whole EMC cert session.

Yes, it would need channel hopping because 433MHz is pretty crowded in many metro areas. It's the only band that is international enough and offers a few hundred meters range for really low bandwidths. 2.45GHz doesn't work well. Initially I thought maybe some DECT device could be used but I am rather disappointed with that standard.

--
Regards, Joerg

http://www.analogconsultants.com/

"gmail" domain blocked because of excessive spam.
Use another domain or send PM.

Realistically around next winter, so there is time. But it must be something where we don't have to EMC-cert it for every market.

Quantities depend on user acceptance. I'd have to ask. Initially probably a few hundred, later thousands per year. So it can't be an elaborate full-custom solution, must be almost off-the-shelf because of the low quantities. There could also be a huge initial demand if existing systems are to be upgraded with this feature.

--
Regards, Joerg

http://www.analogconsultants.com/

"gmail" domain blocked because of excessive spam.
Use another domain or send PM.

I'm not an expert, because I'm just a programmer (and Ocarina player on iPhone since yesterday

:-) , but at least the RF module needs its own PCB and I think as soon as you solder some module to another PCB and put it in a box, you have to test it again.

--
Frank Buss, fb@frank-buss.de
http://www.frank-buss.de, http://www.it4-systems.de