433MHz to LAN gateway or miniserver?
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From: Frank Buss on 3 Apr 2010 16:18 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 :-) -- Frank Buss, fb(a)frank-buss.de http://www.frank-buss.de, http://www.it4-systems.de
From: Joerg on 3 Apr 2010 16:21 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 :-) I assume a motion to get the dome painted with RF absorbant coating on the inside would get dismissed ... >>> 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. -- 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 16:44 Frank Buss 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 :-) > The firewall-router here in the office is a SMC Barricade. It has both a serial port and a parallel port built in. The RS232 is meant to be used as backup if the connection goes down and the other is for a printer. I could imagine one could hack that (but I don't know, other than that people have talked to the router via RS232) and then you wouldn't even have to fire up the solder station :-) -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
From: Jan Panteltje on 3 Apr 2010 18:43 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
From: Joerg on 3 Apr 2010 19:36
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. -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM. |