433MHz to LAN gateway or miniserver?
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From: Joerg on 3 Apr 2010 12:20 Jan Panteltje wrote: > On a sunny day (Fri, 02 Apr 2010 15:30:54 -0700) it happened Joerg > <invalid(a)invalid.invalid> wrote in <81n9h8Fn2pU1(a)mid.individual.net>: > >> 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. > > 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. -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
From: krw on 3 Apr 2010 12:29 On Thu, 01 Apr 2010 19:23:47 -0700, Joerg <invalid(a)invalid.invalid> wrote: >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
From: Joerg on 3 Apr 2010 12:45 krw(a)att.bizzzzzzzzzzzz wrote: > On Fri, 02 Apr 2010 12:51:27 -0700, Joerg <invalid(a)invalid.invalid> wrote: > >> Joel Koltner wrote: >>> "Joerg" <invalid(a)invalid.invalid> wrote in message >>> news:81mo9mFj1nU1(a)mid.individual.net... >>>> Until they have to trudge through the paperwork of EMC cert themselves >>>> for the first time and a check for a princely sum is plopped onto the >>>> table at the compliance lab. >>> 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. > > 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. >>> ... 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. > > 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 :-) -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
From: Joerg on 3 Apr 2010 12:54 krw(a)att.bizzzzzzzzzzzz wrote: > On Thu, 01 Apr 2010 19:23:47 -0700, Joerg <invalid(a)invalid.invalid> wrote: > >> 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? ... 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. -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
From: krw on 3 Apr 2010 15:10
On Sat, 03 Apr 2010 09:45:11 -0700, Joerg <invalid(a)invalid.invalid> wrote: >krw(a)att.bizzzzzzzzzzzz wrote: >> On Fri, 02 Apr 2010 12:51:27 -0700, Joerg <invalid(a)invalid.invalid> wrote: >> >>> Joel Koltner wrote: >>>> "Joerg" <invalid(a)invalid.invalid> wrote in message >>>> news:81mo9mFj1nU1(a)mid.individual.net... >>>>> Until they have to trudge through the paperwork of EMC cert themselves >>>>> for the first time and a check for a princely sum is plopped onto the >>>>> table at the compliance lab. >>>> 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. >> >> 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. ....even if those transmit settings are intended to be mucked with as part of normal operation. >>>> ... 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. >> >> 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. 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. |