433MHz to LAN gateway or miniserver?
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From: krw on 3 Apr 2010 21:20 On Sat, 03 Apr 2010 16:36:01 -0700, Joerg <invalid(a)invalid.invalid> wrote: >Jan Panteltje wrote: >> On a sunny day (Sat, 03 Apr 2010 13:13:46 -0700) it happened Joerg >> <invalid(a)invalid.invalid> wrote in <81pls6Ffh7U1(a)mid.individual.net>: >> >>>> And I am not in USofApe either. >>> >>> Let's keep the tone a bit more professional, shall we? >> >> Yes, sorry typo: >> USofApes > > >You are one of the people from whom I would not have expected rude >remarks like that. Sad. I would. He's been a US hating Europeon for the decade or so I've known him on the Usenet.
From: krw on 4 Apr 2010 00:22 On Sat, 03 Apr 2010 13:21:23 -0700, Joerg <invalid(a)invalid.invalid> wrote: >krw(a)att.bizzzzzzzzzzzz wrote: >> 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. ;-) >> > >Why don't they help at the base if you'd use helixes and the like? The >person can't have one of course and you'd need stage hands to follow >persons with the base antenna. And not smoke any "stuff" while doing >that job :-) Well, the "stage hands" are the users so the unions would be happy to have a stage hand per stage hand (per...) for full employment. >I assume a motion to get the dome painted with RF absorbant coating on >the inside would get dismissed ... I'd think it would have to be pretty good stuff, if it were reasonable financially. The distance off the roof isn't very different than a straight line. 1/r^2 isn't going to help much so the material would have to do everything. >>>> 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. > > >There are ways to use heavily shortened non-protruding antennas down >there, or use any otherwise attached cables as antenna. But not knowing >the app it's hard to say. Shortened antennas aren't as efficient, which is a big problem. We're fine with the 2.4G antenna but it's a close call whether we'll find a suitable antenna at 900MHz. 433 would be twice again the problem. As you alluded to before, though, 900MHz is really only suitable for the US.
From: Nico Coesel on 4 Apr 2010 06:51 Frank Buss <fb(a)frank-buss.de> wrote: >Jan Panteltje wrote: > >> 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 :-) I know someone who turned the Linksys NSL2U into a remote doorbell logging device for 100+ shops from a big franchise. Now they can see exactly how many and when people went into their stores. Modifying the NSL2U was the cheapest way to get the project done. -- Failure does not prove something is impossible, failure simply indicates you are not using the right tools... nico(a)nctdevpuntnl (punt=.) --------------------------------------------------------------
From: Phil Hobbs on 4 Apr 2010 08:04 On 4/4/2010 6:51 AM, Nico Coesel wrote: > Frank Buss<fb(a)frank-buss.de> wrote: > >> Jan Panteltje wrote: >> >>> 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 :-) > > I know someone who turned the Linksys NSL2U into a remote doorbell > logging device for 100+ shops from a big franchise. Now they can see > exactly how many and when people went into their stores. Modifying the > NSL2U was the cheapest way to get the project done. > The Slug is a great little gizmo. I have two running the Unslung distro, keeping 1.5 TB NAS online as well as running a bunch of other utilities. Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal ElectroOptical Innovations 55 Orchard Rd Briarcliff Manor NY 10510 845-480-2058 hobbs at electrooptical dot net http://electrooptical.net
From: Jan Panteltje on 4 Apr 2010 15:51
On a sunny day (Sat, 3 Apr 2010 22:18:23 +0200) it happened Frank Buss <fb(a)frank-buss.de> wrote in <1v7r3zzzl3m2o.1vge5ea30tqqi.dlg(a)40tude.net>: >Jan Panteltje wrote: > >> 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 :-) You can hang my scope_pic from th RS232 and remotely scope anything: *** **** *** *** *** *** * * * * * * * * * * * * * * * * ** * * * * * * * * * ** * * * * * * * * *** ** **** *** *** * * * * * ** * * * * * * * * * * * * * * * * * * * ** * * * * * * * * * * * * * * *** ** * **** ***** *** *** *** * * * * ** ** ** * * * * * *** * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ** * *** * * * ** * * ***** *** *** **** * * * * * * * * * ** * ** * * * **** * * * * * * * * *** * ** * ** * * * * * * * * * * ** * * **** *** *** ** * **** -- **** * * * * * * * * * * * *** * ** ***** *** * ***** ** *** **** * * ** * * * * * * * * * * * * * * * ***** * * * ***** * * * * * * * * * * * * ** * * * ** **** * ** * **** * * * * * * * * * * * * * **** *** * ** ***** *** * ***** ** *** **** *** ** * * * * * * * * * * * ** * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ***** * * * ***** * * * * * * * * * * * * * * * ** **** * * * * * * * * * * ** * * * * * * * * * * * * ** * ** * * * ** **** * ** * **** ** **** *** * * * * ** |