433MHz to LAN gateway or miniserver?
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From: krw on 3 Apr 2010 15:18 On Sat, 03 Apr 2010 09:54:32 -0700, Joerg <invalid(a)invalid.invalid> wrote: >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. That's about our useful limit in normal circumstances. With a lower datarate this shouldn't be a big deal. > >> ... 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 > > >$400 for an industrial bridge won't fly. But yours are for large data >rates which we really don't need. It would be like using a 40-ton truck >to buy the groceries ;-) > >WRT to inter-symbol time the DECT standard must be quite screwed up. >Multipath notch-out happens exactly at the office desk I am normally >using. Hurumph! I want my old Cincinnatti Microwave phone back, they >knew how to do this stuff right without some standards committee sipping >Perrier ... but AFAIK they dropped all this and concentrated on radar >detectors. In our case it's the ceiling of the Super Dome that drives us nuts. ;-) 900MHz is quite promising, but has other issues. Don't know if anyone has looked at 433, but I'm sure the antenna would be next to impossible.
From: Jan Panteltje on 3 Apr 2010 15:39 On a sunny day (Sat, 03 Apr 2010 09:20:56 -0700) it happened Joerg <invalid(a)invalid.invalid> wrote in <81p87jFqvdU3(a)mid.individual.net>: >> A while ago I added some I/O to my Linksys WAP: >> http://panteltje.com/panteltje/wap54g/io.html >> http://panteltje.com/panteltje/pic/io_pic/index.html >> >> So I have it all, wireless, LAN RJ45, analog I/O, digital I/O, >> controlled from anywhere, webserver too on SDcard, the works. >> Couple of dollars only. >> Oh, and it has a buld in temp controller with night and day setpoints. >> remote monitoring of anything you want. >> Oh, and the WAP runs Linux. >> The whole thing is for sure < 100$ 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. > Look dude, your stripes ... WDIC! I have been through that approval stuff before 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, And I am not in USofApe either.
From: Joerg on 3 Apr 2010 15:46 krw(a)att.bizzzzzzzzzzzz wrote: > On Sat, 03 Apr 2010 09:54:32 -0700, Joerg <invalid(a)invalid.invalid> wrote: > >> 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. > > 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. >>> ... 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. > > 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. -- 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 16:12 On Sat, 03 Apr 2010 12:46:57 -0700, Joerg <invalid(a)invalid.invalid> wrote: >krw(a)att.bizzzzzzzzzzzz wrote: >> On Sat, 03 Apr 2010 09:54:32 -0700, Joerg <invalid(a)invalid.invalid> wrote: >> >>> 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. >> >> 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. > > >>>> ... 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. >> >> 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. 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. ;-) >> 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. 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.
From: Joerg on 3 Apr 2010 16:13
Jan Panteltje wrote: > On a sunny day (Sat, 03 Apr 2010 09:20:56 -0700) it happened Joerg > <invalid(a)invalid.invalid> wrote in <81p87jFqvdU3(a)mid.individual.net>: > >>> 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. >> > > 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? -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM. |