433MHz to LAN gateway or miniserver?

[Joerg]

Hmm... so I might guess that something like this:
http://www.elcomresearch.com/shop/item.aspx?itemid=11 ... is operating
in a legal gray zone, at least in the U.S. (they're in Greece)? ...

Not necessarily. If you use a pre-certed module with its native antenna
and just place that pre-certed stuff inside a plastic shroud you can be ok.

... They're
using off-the-shelf GPS and Bluetooth modules in there, but I'm almost
100% certain (from e-mails with the main designer) that they didn't go
through a formal certification process...

Maybe they are just a re-packager when it comes to hardware.

 

[Joerg]

Joergman is paranoia

Nope, but I've got over 20 years of agency approval processes under the
belt

 

[markp]

This time it doesn't have to be super low cost. But at the same time it
shouldn't be over-engineered. This easily happens when standards
committees get together. What's the old saying? Too many cooks spoil the
broth.



Well, if there were off-the-shelf units at reasonable cost I wouldn't care
whether there is a 32bit ARM in there of some lowly 8051.

Note the Jennic modules are 32bit with lots of resources:
http://www.jennic.com/products/modules/

These are very nice modules.Retail for about $16 in volume. Unfortunately
not available for 433MHz only 2.4GHz.

Mark.

 

[Joerg]

Note the Jennic modules are 32bit with lots of resources:
http://www.jennic.com/products/modules/

These are very nice modules.Retail for about $16 in volume. Unfortunately
not available for 433MHz only 2.4GHz.

Yeah, I looked at their site :-(

The other thing that I couldn't find is a LAN link. That's missing in
many systems that are targeted at the home health market. Which I'll
never understand because there are more and more people who don't have a
phone line anymore but they do have broadband Internet access. One of
them in this neighborhood is in her 90's.

 

[Martin Riddle]

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.

I know this is what your looking for, but I have no idea about the
price.
<http://www.pointsix.com/cgi-bin/PointSix.cgi?PManager>

Cheers

 

[Joerg]

I know this is what your looking for, but I have no idea about the
price.
<http://www.pointsix.com/cgi-bin/PointSix.cgi?PManager>

Aha, thanks! They only offer a transceiver for 900MHz, not 433MHz so
we'll have some problems internationally but it can't hurt to talk to
the guys about it.

 

[markp]

Yeah, I looked at their site :-(

The other thing that I couldn't find is a LAN link. That's missing in many
systems that are targeted at the home health market. Which I'll never
understand because there are more and more people who don't have a phone
line anymore but they do have broadband Internet access. One of them in
this neighborhood is in her 90's.

Pity that they don't do 433MHz. The beauty of the Jennic module is that the
32 bit processor has a lot of resources and they provide you with a full IDE
based on CodeBlocks to put your own application in the module itself, in
many cases you don't need anything else. BTW the 6LowPAN dev kit does come
with an LAN board, so the schematics of that are going to be available for
you to embed:
http://www.jennic.com/products/development_kits/jn5139_6lowpan_evaluation_kit

If you could cope with high powered 2.4GHz that might get you the range you
want but might also restrict the markets you could sell in, Jennic also do
high powered versions of those modules.

Mark.

 

[Joerg]

Pity that they don't do 433MHz. The beauty of the Jennic module is that the
32 bit processor has a lot of resources and they provide you with a full IDE
based on CodeBlocks to put your own application in the module itself, in
many cases you don't need anything else. BTW the 6LowPAN dev kit does come
with an LAN board, so the schematics of that are going to be available for
you to embed:
http://www.jennic.com/products/development_kits/jn5139_6lowpan_evaluation_kit

If you could cope with high powered 2.4GHz that might get you the range you
want but might also restrict the markets you could sell in, Jennic also do
high powered versions of those modules.

High-power 2.45GHz can cause serious market restrictions overseas. Also,
ideally we don't want to piece it all together ourselves. The product
line Martin pointed out seems to have the potential for a real
plug-and-play situation:

http://www.pointsix.com/support/documents/PManager.pdf

Ok, no 433MHz transceiver but with our qties they might be willing to
give us that. If their RS232 RF transceiver can talk to this little
server they've got then we'd almost be home, because then we could
simply plug our RS232 lines from the uC in there and be done.

 

[Joerg]

I think it's mainly an installation problem (or at least the perception
of one) -- the average customer can properly plug in a phone, but while
in many instances you'll have, e.g., a router running a DHCP server so
it really is "plug and play" for a home health widget, when it *doesn't*
work troubleshooting is not something grandma can usually do successfully.

True. However, I know a lot of people who have no land line since years.
Including people who must go to the front porch in order to be able to
see if someone left a message on the cell. But all of them have a cable
modem.

Plus companies like Life Alert ("Help, I've fallen and I can't get up!"
-- you know those guys charge something like $40/mo for their system?
Sheesh!) never exactly struck me as being all that technology-savvy anyway.

Well, but for that money they have to have a minimum staffing level and
they also call in regularly. "Hey, how'ya doing today?" I bet that alone
has resulted in ambulance calls before it was too late.

But heck, you've identified a real market need here -- given time,
someone will surely step in to fill it.

I doubt it. Look at the home automation market. Most companies there are
IMHO sound asleep.

 

[krw@att.bizzzzzzzzzzzz]

Not necessarily. If you use a pre-certed module with its native antenna
and just place that pre-certed stuff inside a plastic shroud you can be ok.

If you've added no function to the box, perhaps. Add any function and you
have to certify again, often on a country by country basis (particularly in
Asia).

Maybe they are just a re-packager when it comes to hardware.

Or they're skirting the law. In the US they're unlikely to get into hot water
unless someone turns them in (often a competitor).

 

[Joerg]

A while ago I added some I/O to my Linksys WAP:
http://panteltje.com/panteltje/wap54g/io.html
http://panteltje.com/panteltje/pic/io_pic/index.html

So I have it all, wireless, LAN RJ45, analog I/O, digital I/O,
controlled from anywhere, webserver too on SDcard, the works.
Couple of dollars only.
Oh, and it has a buld in temp controller with night and day setpoints.
remote monitoring of anything you want.
Oh, and the WAP runs Linux.
The whole thing is for sure < 100$ i none of quantities.

Ahead again.

For hobby, yes. For a commercial product that goes into the consumer
market, very different thing. The millisecond you hack a device that
contains a two-way radio function you are back to zero WRT agency
approvals. T'is life

If you don't believe me or think I am paranoid or whatever then ask a
guy at an accredited lab or a senior underwriter at a product liability
carrier. And yes, compliance is required pretty much worldwide.

 

[krw@att.bizzzzzzzzzzzz]

Is there a cheap (as in mass produced and <$100) pod that plugs into a
LAN port of a regular router and have a, say, 433MHz radio link?
Something that could then connect to several thermometers or weather
stations and ask for their readings.

It would have to be accessible from the web by a remote server for
polling purposes. Maybe it could just be a mini webserver in itself that
gets polled. 2.45GHz often wouldn't work all that well because of range.

How much range do you need? We're quite happy at 2.4G, except where there is
massive multi-path that just happens to be just far enough away to match our
inter-symbol time. For those few places, 900MHz looks like the answer if we
can get the antenna right. Our module is expensive and our bandwidth
requirements are much more than yours so maybe there is something cheaper that
would work.

http://www.rfm.com/products/oem_standalone.php

 

[Joerg]

If you've added no function to the box, perhaps. Add any function and you
have to certify again, often on a country by country basis (particularly in
Asia).

Yup, if it's a function that mucks with the transmit protocol or xmit
settings in any way you usually need to re-cert.

Or they're skirting the law. In the US they're unlikely to get into hot water
unless someone turns them in (often a competitor).

.... and that's exactly what can happen. Some competitors look for the
slightest infraction to rat out their neighbor.

Maybe Jan has never worked in the RF business. It's a jungle out there

 

[Joerg]

How much range do you need? ...

About 300 meters or 1000ft. However, that includes RF-unfriendly turf.
2.45GHz with really long correlation can work but that sort of requires
an AM protocol which is interference-prone.

... We're quite happy at 2.4G, except where there is
massive multi-path that just happens to be just far enough away to match our
inter-symbol time. For those few places, 900MHz looks like the answer if we
can get the antenna right. Our module is expensive and our bandwidth
requirements are much more than yours so maybe there is something cheaper that
would work.

http://www.rfm.com/products/oem_standalone.php

$400 for an industrial bridge won't fly. But yours are for large data
rates which we really don't need. It would be like using a 40-ton truck
to buy the groceries ;-)

WRT to inter-symbol time the DECT standard must be quite screwed up.
Multipath notch-out happens exactly at the office desk I am normally
using. Hurumph! I want my old Cincinnatti Microwave phone back, they
knew how to do this stuff right without some standards committee sipping
Perrier ... but AFAIK they dropped all this and concentrated on radar
detectors.

 

[krw@att.bizzzzzzzzzzzz]

Yup, if it's a function that mucks with the transmit protocol or xmit
settings in any way you usually need to re-cert.

....even if those transmit settings are intended to be mucked with as part of
normal operation.

... and that's exactly what can happen. Some competitors look for the
slightest infraction to rat out their neighbor.

Been there. It keeps the lawyers employed.

Maybe Jan has never worked in the RF business. It's a jungle out there

It's not just RF products. Anything to do with RF compliance or even safety
certifications can fall into this category.

 

[krw@att.bizzzzzzzzzzzz]

About 300 meters or 1000ft. However, that includes RF-unfriendly turf.
2.45GHz with really long correlation can work but that sort of requires
an AM protocol which is interference-prone.

That's about our useful limit in normal circumstances. With a lower datarate
this shouldn't be a big deal.

$400 for an industrial bridge won't fly. But yours are for large data
rates which we really don't need. It would be like using a 40-ton truck
to buy the groceries ;-)

WRT to inter-symbol time the DECT standard must be quite screwed up.
Multipath notch-out happens exactly at the office desk I am normally
using. Hurumph! I want my old Cincinnatti Microwave phone back, they
knew how to do this stuff right without some standards committee sipping
Perrier ... but AFAIK they dropped all this and concentrated on radar
detectors.

In our case it's the ceiling of the Super Dome that drives us nuts. ;-)
900MHz is quite promising, but has other issues. Don't know if anyone has
looked at 433, but I'm sure the antenna would be next to impossible.

 

[Joerg]

That's about our useful limit in normal circumstances. With a lower datarate
this shouldn't be a big deal.

Normal circumstances in this case could mean a tropical storm barreling
through while still needing to transmit.

In our case it's the ceiling of the Super Dome that drives us nuts. ;-)

That I can surely believe, it's a massive structure. You'll probably
have to prop up an arsenal of directional antennas.

900MHz is quite promising, but has other issues. Don't know if anyone has
looked at 433, but I'm sure the antenna would be next to impossible.

Right now we are using 418MHz quite successfully. But of course for
international markets it would be better to move to 433MHz, pretty much
the only option other than the GHz bands. Antennas aren't a challenge in
our case, it's the short rubber duckies.

 

[krw@att.bizzzzzzzzzzzz]

Normal circumstances in this case could mean a tropical storm barreling
through while still needing to transmit.




That I can surely believe, it's a massive structure. You'll probably
have to prop up an arsenal of directional antennas.

Other domes aren't such a problem (though the new Dallas domed stadium is
another). Directional antennas don't help on the base (even on the ceiling
pointed down) and don't work very well attached to a human walking about. ;-)

Right now we are using 418MHz quite successfully. But of course for
international markets it would be better to move to 433MHz, pretty much
the only option other than the GHz bands. Antennas aren't a challenge in
our case, it's the short rubber duckies.

That's what we're using for the base. The mobile unit has a patch built into
it (no protrusions). That's a problem below 2.4G.

 

[Joerg]

Look dude, your stripes ... WDIC!

Well, my clients care and so I have to

I have been through that approval stuff before

Then you should know that what you write below can void a cert. It is
very easy to say "Oh, it's all a piece of cake". You have a good
knowledge of electronics and you can do it. So could I. Except that my
stuff is not hobby, therefore ...

The WAP has a hidden serial port, I connect to it.
F*ck your objections to anything, I am merely pointing out how it can be done,
how I did it, so that it already exists,
and if you do not like it find your own solutions.
This is about design, not about your frustration with some agency,

In Europe the rules and regs are even more onerous. BTDT, lived there,
worked there, did radio certs there. Has nothing to do with frustration
and I don't have any. However, such agencies make the laws and are the law.

And I am not in USofApe either.

Let's keep the tone a bit more professional, shall we?

 

[Frank Buss]

A while ago I added some I/O to my Linksys WAP:
http://panteltje.com/panteltje/wap54g/io.html
http://panteltje.com/panteltje/pic/io_pic/index.html

Nice project! I have a Linkstation (a NAS) and installed a custom firmware
and a regular Debian system some time ago (Apache works without problems).
Looks like a serial port can be added to this device, too:

http://buffalo.nas-central.org/index.php/Add_a_Serial_port_to_the_ARM9_Linkstation

A NAS with 500 GB hardddisk for 100 euro and the capability to add custom
hardware with a simple serial port protocol and control it from a Linux
system, sounds like some interesting ideas can be implemented with it
without much work. A long-term recording seismometer with high sample rate
would be cool