Page tested for compliance with INDUSTRY (not MS-only) standards, using the free, publicly accessible validator at validator.w3.org. Mostly passes.Update: December 2013: Hummm... some of this is a bit of a stroll down memory lane! Lots of "pioneers from the good old days" listed here. But some of the following are still active, and I hope the page remains valuable, not only for them, but for some current useful vendors, too. (I have been a bit inactive in creating new 1-Wire material in the past few years... but I have a number of systems running smoothly. I haven't stopped using 1-Wire... I'm just not trying every new 1-Wire toy these days... (Arduino... which also does 1-Wire, by the way... has been soaking up time. (Neither soak up much money!))
We'll get to "the good stuff" in a moment, I promise, but there are a bunch of things that ought to be said first. Click here to skip down to the main content of this page.
Let me start by explaining that I have little or no connection with Dallas or the following at the time I write this, though I've had samples to test and have been given links in some cases. I would love to get my weather monitor software distributed by any of the following, too! I've been a customer of many of them. (There's a note for suppliers near the bottom of the page.)
"1-Wire" and "MicroLan" are all trademarks of Maxim, who now own Dallas Semiconductor, who developed 1-Wire. Can we put the lawyers back in their box now? The chip family has been in production for many years. One member of the family provides the people of Istanbul Turkey with "electronic wallets" to pay for mass transit, among other 1-Wire triumphs.
Ads from the editor of this page: (← link opens page with contact details)
1) I have a design for a MicroLan controlled relay, which you are free to use.
2) I have a working prototype for a DS2408 based board which offers 8 bits of opto-isolator protected input.
3) Could you use a way to check up on your home or a business premise from any internet connected PC? using only free software? (You will need a Windows PC and always-on internet connection at the monitored premises.) I've explored and written up everything you need to know. I call it FarWatch, and have had two premises monitored with FarWatch installations for many years.
4) I've created a small PCB with a DS2423 counter and a simple oscillator running at about 10Hz. Off board switches connect (or don't connect) the output of the oscillator to the input of the counter. The device is for jobs like monitoring a door. When has it been opened? How long was it open? The counter is read from time to time, but it doesn't have to be often. The value in the counter indicates how long the door has been open, even if the door is closed again by the time the system re-visits the counter. I hope someone will produce a PCB for this circuit. I won't pay them, or give them an exclusive license, but they get the profits from selling the board.
5) (Not 1-Wire specific) I have extensive notes about a small, hobbyist- buildable PCB for protecting lines to and from a microprocessor, e.g. the Arduino, or a computer's parallel port. The design provides for 4 opto-isolator protected inputs to the port, and 4 driver circuits and relays so the port can send outputs. As with "4" above, I hope someone will release a board, although I realize that parallel port interfacing is "so yesterday", and that similar boards already exist!
The page you are reading lists.....
assembled units which you will merely "plug in",
kits which you will have to assemble,
bare PCBs, and
even mere circuit diagrams.
Elsewhere, I provide help with writing software for most of the devices on this page. Most of them are also supported by programs already in the marketplace, if you don't want to write your own. I happen to work in Delphi, but my tutorials should be useful regardless of which language or OS you use. There is, for instance, a thriving Linux 1-Wire programming community.
Links to sections of this page, and rough table of contents....
Denkovi Electronics (from at least 2013)
Peter Anderson (from at least 2005)
Simon Atkins (from at least 2010)
WeatherToys (from at least 2010)
Weather Projects (from at least 2013)
IT Watchdogs (from at least 2013)
iButtonLink (from at least 2008)
Systronics (from at least 2013)
Midon Design (from at least 2013)
Embedded Data Systems (from at least 2013)
Information on old Dallas designs (from at least 2013)
Tuscon Amateur Packet Radio (from at least 2013)
Sheepwalk Electronics, Yorkshire, England (from at least 2013)
PCSensor.com, Hong Kong (from at least 2011)
---------------
Time like an ever rolling stream.... The following were once great sources. Alas, 11/21, they no longer seem to be with us....
AAG
Hobby Boards (Eric Vickery)
Springbok Digitronics (David Lissiuk)
Sensiron
"Memorial" section ends
... and there is "general stuff" at the bottom of the page!
The information given below may well be out of date. It is presented only to give you an idea of what was at least once available from the sites. Where nothing is said about shipping, the prices given exclude shipping.
Buyer beware: In the first part of 2007 I "bought" some 1-Wire chips via eBay; paid via PayPal... which is supposed to protect you? (Certainly there's a scam that bad buyers can pull on good sellers.) Goods never arrived, and when I went through the (tortuous) channels at eBay and their subsidiary PayPal, I was eventually told "Tough. You lose." Not long after that tiresome experience, I found someone new selling 1-Wire chips at eBay. Also quoting prices in Polish zolty. And if you look at his "good rep", quite a few points were generated by him as a buyer, and quite a few of the feedback comments looked remarkably similar. There ARE good sellers of 1-Wire stuff online... but be careful. Months later, I tried a similar source again, and this time my goods arrived promptly, "as new" condition.
Denkovi Electronics: December 2013, I was delighted to discover a new (to me) player in the 1-Wire world. I bought a USB -> 1-Wire interface from Denkovi Electronics, in Bulgaria, via eBay. It cost about the same as a LinkUSBI, a similar device from iButtonLink, a long-standing source of 1-Wire products... but, give "the new kids" a try? I got one of the Denkovi interfaces up and running with no problems. You do need to supply your own USB cable, and it doesn't come in an enclosure... but I like it! And doing business with them was painless. The Denkovi device probably doesn't offer the ASCII comms option, but it uses proper screw terminals instead of the wretched phone jacks used by so many 1-Wire manufacturers. The Denkovi device has also provided RC filtering (which may be present in the iButtonLink product)... which you can bypass, if you don't want it. (No option with the iButtonLink product.)
AAG, Mexico: (Stop press: This entry may be dated, at 12/13, for http://www.aagelectronica.com, I got "site under maintenance" when I tried it, and it didn't show up well in a Google search. (The company was also once at www.aag.com.mx, if you are being obsessive!) Even if the firm is "gone", their products were good, and will probably be available via eBay, etc, for a while.) This Mexican firm is? was? a serious commercial venture. (Some of the other distributors, below, are hobbyists). Their customer care is first rate. They sell a range of 1-Wire modules. They also sell a very well made wind direction and speed sensor. They supply rain gauges. (The wind sensor and the rain gauge are the devices once sold by Dallas.) I hope to give you a better list later of what they have on offer, but I before then I want at least to highlight their "TAI8558": It is based on a DS2408 and has 4 channels of opto-isolator protected input, 4 channels of output via relay. All 8 have on-board LEDs indicating the state of each line. $70. Click here for their site.
More on AAG: I have written a fairly comprehensive application note covering using the TAI8558, and writing software for it. In the note, I work up, just as an illustration, using a TAI8558 for a burglar alarm and heating control. Click here for the pfd with that note. (It is a self contained introduction to many aspects of MicroLan use.) You can download the relevant Delphi source code by clicking here, and the exe file is available here. The latter two files are self extracting archives which will merely install some files, not interfere with your registry, etc.
AAG has many good products: LCD display interface, counter modules, humidity, pressure, etc! Go to the "sensors and actuators" panel of their site. (Ignore the tool tip if it still says 8558 "available soon". It is available now.) Especially if you don't have broadband: don't go away too soon... there's lots of good stuff, but it takes time to load.
For any 1-Wire work, you need an interface between the 1-Wire circuit and a supervising PC. AAG sell both the iButtonLink (a DS9097 replacement) and a USB interface. ($40 and $25 respectively.)(iButtonLink also available direct from manufacturer.)
Their TAI8586 counter module ($30) can monitor pulses on two channels. The inputs are put through opto-isolators which is a Good Thing.
AAG has been selling 1-Wire stuff since at least 2001. I'm not sure if they accept PayPal, but I think they do. Many people in discussion groups have said that they appreciate the good service and sincere desire to be helpful that they experience when dealing with AAG, specifically when they've dealt with Aitor Arrieta. I agree.
Update: 7/09
THEY MOVED MY CHEESE ! !
It seems that the long time excellent wind speed/direction sensor has been replaced. It was based on a Dallas DS2450, and you can probably still get them via eBay.
The replacement for that, also from AAG, seems to have much more electronics in the sensor head. A good thing in some ways... just be careful that you know WHICH wind speed/direction unit you are working with. For one thing, the new one puts different signals on the pins of the connector... plug in the wrong device, and you could have serious problems. If the unit in question has a clear body, and decorative LEDs, it is the "new" device.
Hobby-Boards: For many years, Eric Vickery sold 1-Wire hardware though his www.hobby-boards.com.
Sadly that ended in early 2016... but even though I miss Hobby Boards, I do wish Eric well in his retirement! For further details of what was available see my tribute to Eric and Hobby Boards.
If you are aware of anyone selling what he used to sell, I will be very pleased if you contact me! I will investigate suggestions, consider adding links to this page. (That goes for any good 1-Wire provider's sites!)
Still available: I have produced a free DLL which lets you easily access the Hobby Boards Mini Motion detector (or any other DS2405 based sensor) from any serious language. The zip archive has further explanations for you.
The Bray Barometer, once available from HobbyBoards, may still (5/16) be available from FarCircuits. (Go to ther root URL, www.farcircuits.net, for instructions on ordering. The Bray barometer may be somewhat dated, but I have two which are still working fine, having served me for years. (I first said that in 2011, so maybe I should say "served me for many years, in terms of microelectronics!)
Peter Anderson: (12/13): I fear that Mr. Anderson's site was in the early stages of wrapping up near the end of 2013, and that process continued. He gave us some splendid stuff over the years, for which I am grateful. Some of his designs remain available, at least for the time being, from a variety of other sites, Modern Device's, for a start.
Peter H. Anderson, 1946-2012, was an associate professor in the Department of Electrical Engineering at Morgan State University, in Maryland, USA. Although he passed away, his site lives on (checked 5/16), and has Good Stuff for you at. At one point, he introduced it as being about "Embedded Processor Control PC Parallel Port, BasicX, BASIC Stamp®, 68HC11, PIC®, PICAXE, Data Acquisition and Control", so you can see that it has been around for a while. Also his some Arduino stuff page is still available 5/16. There's more there than just 1-Wire stuff, but there is lots of good 1-Wire stuff, including....
His TM#128 is a great way for non programmers to "get into" 1-Wire / MicroLan. For US$45 + p&p (6/05) you get a neat little PCB which you connect to your serial port. You send it a byte (HyperTerminal will do) and it "answers back" with the values in temperature sensors, counters, ADCs attached to the TM#128 by just the two MicroLan wires. You are spared all of the "fun" of writing programs to access the chips. Your $45 gets you the PCB, assembled and tested, a "wall wart" transformer (110v only, I'm afraid... the power requirements aren't hard to meet, though, if you live outside the 110v zone), a serial cable, and a temperature sensor. There's also a kit for less. Extra sensors cost mere dollars. You can have 32 devices on up to 200 feet of MicroLan. You even get the pillars to mount the device in whatever enclosure you decide to use.
His TM#129 (US$20 at 6/05) seems to be the essentials of the above, in kit form.
To read the device, and others in this product line, I suspect, I have written a program in Delphi, which is available (free, at 5/05) with sourcecode. It isn't perfect... but it works, and would be a starting place for other Delphi programmers.
Besides being able to find and read DS1820 and similar temperature sensors, the unit can also find and read DS2423 counters (so wind speed and many, many other things are readable), DS2450 quad ADCs (so the AAG / Dallas wind speed & direction sensor is readable), DS2438 "battery monitor", which is pretty cool... reports local temperature and the "answer" from an ADC... so the AAG humidity sensor (and many other things) is readable.) (If you bought a TM#128 before 1 April 05, you can upgrade to all that functionality for $5... see Peter's site.)
The serial interface uses only GND, TX and RX. You could read the device through a USB to serial converter if you wished to. You could read a TM#128 across the internet of a LAN with one of HWgroup's I/O Controllers!
Oh yes! There's even one TTL i/p on the TM#128. (Couldn't leave that "bit" (in both senses!) out!)
He was that rare combination: A non-commercial presence on the web, who just wanted to share what he'd mastered, and someone who actually knew what he was talking about. And he supplied the bits and pieces you need, piece-meal, in kit form, or assembled modules.
-----------
Also from Peter Anderson, IOM#135E, and IOM#136 $60 assembled and tested. They are similar to the above, but add 8 digital outputs, 6 digital inputs, i/o lines and some 10 or 12 bit ADCs. They differ from one another in their ADC and 1-Wire capabilities, but both offer significant 1-Wire connectivity. they can both read 1-Wire temperature sensors, counters and ADCs (Why more ADCs? The 1-Wire means that the ADC can be away from the PC.) The slight "downside" of this extra capability is a very slightly more complex protocol for "talking" to the device. These are also available in USB versions, which not only spare you the "joys" of serial comms, but also draw their power from the USB socket. At 6/05 they cost US$70, assembled.
Kit LCD #105 includes similar features, with LCD driving built in. For the least expensive option, you can choose a 20X4 Character LCD and you'll only spend $25. There's a similar assembled product if you don't want to deal with connecting the bits.
I should mention that the kits require some experience. Everything you need is well presented, but you have to bring some skills and knowledge to the table. They are not for rank beginners, but they are well documented, and good "learning experiences" for the hobbyist with intermediate skills.
I've left the descriptions of the kits here because someone may, please, one day make them available again... or maybe someone will reverse engineer new equivalents? I will be pleased to provide advertising (no charge) if there are sites doing either. (Subject to checking, of course.)
Springbok Digitronics: A number of useful modules were in the final stages of being released in late May 2004. I have personally seen both the humidity module (It can be adapted for monitoring a variety of things.... it has a ADC chip. It also has a temperature sensor, and some EEPROM) and the module for receiving an iButton. It also has a temperature sensor. There's more on my experiences with these modules here.
A feature of the modules is that the main chips are "downstream" from a DS2409 coupler chip (as used in hubs) so, by manipulating (through software) the switches in the coupler, you can hide things from the MicroLan. Also, all of the boards incorporate a DS2433 (512 bytes) EEPROM on the Aux line. If you don't care for the EEPROM, you can remove the hub chip and hard-wire the "switch" it contained... but that seems a terrible thing to do to a nice little board. I have written a pdf document explaining programming the DS2409. It is addressed to Delphi programmers, but others should find plenty of useful information, too. Also on the web is some related sourcecode.
The source of these modules is David Lissiuk. I've seen various posts by him over the years. He is by nature a careful designer, trying to take care of many "small details" that other people are prepared to let slide. While is site and the release of modules for the rest of us to buy and enjoy is new at May 2004, he is far from being a newcomer to 1-Wire electronics.
Springbok Digitronics
Simon Atkins: Simon is primarily a source of information about using 1-Wire, but he does have (at May 2004) a few PCBs for the "Version 3" barometer.... BARE BOARDS ONLY... no parts, no assembly for you! I've had two of these barometers running for over a year, 100% satisfactory. If you can't get the board from Simon or Hobby-Boards (see above), you may want to try FarCircuits, though they do not offer a kit.
Simon Atkins
Weathertoys: Book and Website: Both discuss lots of fun things about building your own weather station. There is good coverage of using 1-Wire devices, but both the book and the site look at other answers, too. In May 2007, it was quite recently launched, but the site is not "under construction". There's lots of good stuff there.
Weathertoys
Weather Projects: There is some overlap between this site and the one just listed, but there's lots of good stuff here that isn't on the other, hence the "double" listing. This is the site of Tim Bitson, who has been doing things with 1-Wire and the weather, and general fun things for a long time.
Weather Projects. (At 8/11, when I was updating this link, Tim's homepage took you to his "Yet Another Arduino Site"... yes, the Arduino microcontroller claims another fan! (At 12/13 there were plenty of signs that Tim is still active... but I could no longer find a site managed by him.)
ITWatchDogs: This is a commercial site. They have a device called the Weather Duck, $199. It was designed to monitor server rooms, but could be put to may uses. It monitors a whole bunch of things: Temperature, humidity, airflow, 4 general purpose inputs (digital or analog... I think), light level. Can also act as interface for more 1-Wire devices... again: I think. Clever! They also have a number of other units. to get the most from it, you need Linux, WinNT, 2000 or XT... but it will do things for Win98 users, too. (You "talk" to it via ASCII on a serial port.)
To read the device, I have written a program in Delphi, which is available (free, at 5/05) with sourcecode. It isn't perfect... but it works, and would be a starting place for other Delphi programmers. Additional software comes with the device.
They also have some other interesting things...
WeatherGoose: Contains internal Web server, rack mount option, $389
Remote air-flow/ temperature sensor, $50
Devices for monitoring electrical current: 30, 60, or 120 amp current transducers.
Power Egg - monitors volts, amps, watts, and accumulated KWh.
All of the above from ITWatchDogs
iButtonLink: (Stop press: I was going through my site, December 2013, looking at the entries. I was sad to have to put "stop press" notices against some, saying that perhaps the supplier was no longer in business. However, iButtonLink provided a happy contrast. They seem to go from strength to strength! I first knew them, 2004, or maybe before, as the source of something I think they called the iButtonLink. That has, for some time, been called (first) the "LinkUSB", and at Dec 13, the equivalent seems to be their LinkUSBI. At one time I think it was the firm's flagship product. BAck when it was introduced, some felt was superior to the DS9097 Dallas sold at the time. It is a replacement for the DS9097, but does more than it does. And it attaches to your computer via USB, in physical terms, but it creates a virtual serial port, so it "looks" like something on a COM port, to the software. The iButtonLink, with USPS priority mail was $39 at May 2004, and only a dollar more at May 2010. December 2013 sees the LinkUSBI at $32 plus p&p.
One of the "spare" connectors on the usual RJ-45 connector to the MicroLan gives you 5v, which can be useful.
Not only can you use it as a simple DS9097 replacement, but you can also use it to "talk to" your MicroLan via ASCII commands, i.e. with something like HyperTerminal, or "PuTTY", the freeware replacement for that Microsoft battered stalwart.
Once upon a time, I felt it necessary to include the following warning. I hope it is no longer necessary, but just in case: Be careful when ordering. There may be a not-prominent box which you must un-tick if you don't want to you will get marketing email from "all our stores", I think the phrase was. Common enough when you deal with "the big boys", but less common in the universe of smaller suppliers who tend to respect customers more than the big boys. An opt-in might be okay... but I for one resent having to opt out... but three cheers for free enterprise! Caveat emptor works a lot better than Big Brother running things.
In early May 2010 I was setting a new computer (XP) up with 1-Wire drivers. The then current 4.03 drivers and OneWireViewer had trouble seeing the LinkUSB. I reverted to some 4.02 drivers for which I was lucky enough to still have a setup file (it wasn't available from the Dallas site, that I could tell), and everything worked fine. Given iButtonLink's track record, I would expect that whatever glitch was getting in my way has probably been resolved by now.
iButtonLink also have a clever little device called the LinkTH. You plug it into a serial port, and plug a sensor into it, and the computer can now read temperatures and humidities from the LinkTH with a simple ASCII communication. The LinkTH, minus sensor, was $39 at May 2004. Many temperature/ humidity sensors can be added to a single LinkTH. (The LinkUSBI also offers ASCII comms to the MicroLan, but maybe the "language" is lower level? I don't know why else there would be two products.)
Systronix: These people are good supporters of the Dallas "TINI": A really cool 3 square inches of PCB!! It looks a little like a memory SIMM, but consists of a computer, Ethernet interface, Java machine, 1-Wire interface, etc! Not for inexperienced users, but certainly something to aspire to "driving"!!
Systronix are patient with people at the base of the learning curve, and have provided good online TINI tutorials.
Systronix (N.B. systronIX, not systronICS)
Sensirion: There is a great little humidity / temperature sensor from Sensirion, but it is not designed to interface with the 1-Wire system, but it can be done! If you want to connect one to a 1-Wire LAN, consider Thomas Rudolphi's unit with a PIC to take care of the interface. There is more on the device at my general miscellaneous weather sensors page
Someone made a 1-Wire interface for the humidity-sensor SHT11 from Sensirion.
Designer tells us it's based on a PIC16F84 uController of Microchip. Besides the SHT11 connection there are 10 I/O pins accessible by 1-Wire. The PIC controls on a single 1-Wire command the complete I2C communication of the SHT11 and converts both temp and humidity in one cycle. Results are presented in a 10 bytes message ( sensor bytes + some extra chars )
There's more info at: http://home.kpn.nl/thomas_7/1Wire/1-WireIOPort.html
Midon Design In April 2005, I became aware of another promising source of 1-Wire hardware, Midon Design. They sell assembled units, kits, and bare boards. They really do seem to want to give you what you want. Much appreciated.
At April 05, a small bare PCB for a temperature sensor, humidity sensor, and ADC for the latter cost $6, plus p&p.
Most of their products are flexible, and can be configured various ways. For example, the board just mentioned does not have to be populated with all of the possible features.
They also have a stand-alone data logger, an alternative RS232-to-MicroLan adapter, relay output boards, DS2408 or DS2405 opto-isolator protected input devices, etc!
While most of my focus has been on weather monitoring by 1-Wire, Midon also pays significant attention to the possibilities for home automation. Visit their site! Midon Design
Embedded Data Systems: At Embedded Data System's site, you'll find something called the Ha7e described. (Cost $39). It is a little box that plugs into your PC's serial port and to a MicroLan. If I read the sales blurb right (I haven't played with one), you control and read from it with simple ASCII commands. It controls a MicroLan for you, taking care of the sorts of things us "real men" ("real engineer-people" just doesn't cut it. Sorry ladies.) have struggled to master in the many paragraphs above. So, for example, I think you can say (in an abbreviated language, of course) "Tell me the number of the first chip on the MicroLan." Then you start a loop "Tell me the next until you tell me there are no more." Then, knowing the numbers (and from them the sort of device each is), you could say, for instance, "DS1820 (temperature sensor) number 42652: Take a temperature reading, and tell me what you find." (In case it wasn't clear before: This is the essence of what we did in the many paragraphs above... but (if I read the sales stuff right) the HA7E makes it much easier to hold the conversation with the MicroLan.)
Embedded Data Systems seem to have a broad offering, but they also seem to be quite expensive.... $30 for a DS18S20 (9 bit resolution) in a little box no the end of a length of wire. $5 for an RJ-11 plug on the wire. Perhaps directed more at the industrial user spending someone else's money than at the hobbyist. And perhaps that is the price they have to charge to cover the hand-holding that some customers seem to see as their "right".... Maybe Alan Heaberlin and Jim Jennings (see below) failed to include enough for this in their business plans. And, oh yes, don't forget building into your plans coping with delivery-from-Dallas problems.
Dallas Humidity / Light: Dallas were working on a humidity / light levels sensor, but that project stalled, I think. There was once a good two page description of a simple - to - build 1-Wire humidity sensor at http://pdfserv.maxim-ic.com/arpdf/AppNotes/humsensor.pdf. The article was by Dan Awtry, then of Dallas. You will need to do your own PCB fabrication and assembly. Or you can just buy a comparable device from AAG for (5/06) US$38 + p&p. (AAG Part TAI8540B.) The article shows you how to interface an HIH-3610 (or is it an HIH-3605... or is one just an improved version of the other? My notes are ambiguous.) to a MicroLan via a DS2438. Besides those two chips, there's just a few passive components to include. The circuit powers everything parasitically. (At 8/11, the sensor chip this used is dated, and there are a number of suppliers of complete boards with the descendant chip, or others.)
Tragic losses!: A gentleman named Jim Jennings once had a great site with some great designs. He sold bare PCBs. His site had all the support a hobbyist needed: Circuit diagrams and annotated PCB layouts. He seems to have retired. If anyone can forward this plea to him: Please: If you have retired, would you either release your work into the public domain, or at least let us know who has the rights now?
Another tragic loss: For a time, Mr Alan Heaberlin was doing great work, supplying bare PCBs and kits. It seems that other interests have taken over. His masterpieces were a hub, and a barometer. Neither were his design, but he did sterling work putting together kits for interested parties. The barometer was the Atkins/Bray design. (UK readers may wish to go to Simon Atkins' site, or Hobby-Boards, or FarCircuits (see above.) He had a few blank PCBs... not kits of parts.. left last time I spoke with him.) The barometer was a joint effort of the members of the Dalsemi Weather mailing list in the first half of 2002. If you acquire a kit, you are welcome to click here for my assembly instructions. That page also has further notes on obtaining the unit. (And the names of some folks who do assembly, in case you bought a kit and had second thoughts!) There are many SMT device in it, but I've assembled two with no special tools, though a delicate soldering iron and very thin solder help. It is a nice little unit which takes the output from a Motorola MPXA4115A, passes it through an op-amp, and then that signal is presented to the 1-Wire via a DS2438. The DS2438 also has a temperature sensor in it, but it is near some voltage regulators, so you need to mount the device carefully if you want to read the local temperature as well as the pressure. The DS2438 reads to 0.03 Celsius degree, if I've read the data sheet correctly!
Alan and/ or Jim also supplied a Lightning Detector. Click here for my assembly instructions if you buy that as a kit. There's only one SMT device in it, so it isn't very difficult to assemble. (In July 2011, I built and installed an X1W-4 EMP kit ($22+ p&p at 8/11) (lightning detector) from "TAPR", the Tucson Amateur Packet Radio group. It was well designed, and I am now recording many more electromagnetic pulses, like the ones from thunder storms... mostly the electrically noisy motor in my air conditioner! Worth checking out. You will need to connect it to a DS2423 counter, such as the ones sold by Hobby Boards.)
If you're interested in lightning detection, you should read the section on my page about general weather sensors. Details of an approach are explained there. With what's there, and something like a DS2438, you could read the information into a 1-Wire system. I strongly suspect that you could adapt either a Bray Barometer unit, or a Springbok LP-THS unit to read the signal from the antenna described in the section just referenced. You might have to change some resistors to adjust the behavior of the Bray board's amplifier, or provide the op amp off-board for the Springbok. (LP-THS not yet quite in the marketplace at 10/04... but headed for it!)
Alan was also working on a humidity sensor which also used a DS2438, and it didn't have the voltage regulators, making another device that could sense temperature, too, if your software could access it.
Working from memory, I'm pretty sure that Alan and/ or Jim also offered the following. I've put the chip they are based on and bare PCB price in brackets after the descriptions in case you write your own software. Counters ($7 DS2423, for windspeed, rainfall, what-have-you), a barometer (DS2438), a hub, a humidity sensor (DS2438), a lightning sensor ($7 DS2423). I use their versions of everything except the hub, and I have one of those, but have not assembled it yet.
At 10/04, it looks as if Eric Vickery's Hobby Boards may be offering what was once on Alan and Jim's sites! (See above)
This next stuff doesn't really "belong" here... and it is somewhat dated at 8/11... but I was in the midst of a big edit session when I wrote it, couldn't think where else to put it, and parked it here.
Take an anti-frustration tablet before starting in at Dallas's site. Remember that what you are tapping into is provided FREE. There IS a lot of good stuff there, but sometimes I can't find things even when I know what I'm looking for. (Of course, Google usually rescues me, if it comes to that... for things I know are there.) Some of the information is incorrect, but only in the sense that something posted in, say, Jan 2000 saying a device is planned for release in April 2000 may still be on the web in August even though a different page is saying that device is going to come out in December. Send the details to Dallas if you like, but it may be a waste of time.
That is NOT to say I don't like what they do. Their 1-Wire products DO work, ARE great fun. Their site DOES have lots of valuable information. Just don't go there if you have no patience. As an example: Suppose you want the pdf data sheet for the DS2438, for its ADC component. I've lost the URLs, I'm working from memory, but in one list of "all" 1-Wire chips' datasheets: no DS2438. A search: nothing. But.... go to what I think they call the "parametric" tree, a sublevel off of 1-Wire is for "Battery protectors". Click that, and a DS2438 pdf CAN be downloaded. Ah well.
A great thing about their pages: I can move around them in the browser of my choice. They don't require the latest and greatest toys devised to keep us on the upgrade trail. They don't require MegaScrew browsers.
Have I been nice enough? Back to being nasty: A long time ago, at 8/11, ordering from Dallas could be a nightmare. (I haven't used them for a while at 8/11.) Don't despair. It IS possible to get their products. IT IS worth it. Some people say they have no trouble with online ordering. Others prefer to use the phone... which in itself can be an "adventure"... and others buy their parts from secondary distributors. Just Hang In There.... this is the 21st century, after all. Repeat after me: All corporations are there for their convenience. We are very lucky that they will sometimes take our money for the products we want.
Tucson Amateur Packet Radio: Is an organization which has produced a number of 1-Wire boards. In July 2011, I ordered one of their lightning detector kits, and like what I got. There are some interesting circuit schematics at the site. To see one, drill down to a specific kit.
Sheepwalk Electronics, Yorkshire, England: Around since at least 2010. Must be doing something right! ("Since 2010"? Check out sheepwalkelectronics.co.uk at the Internet Wayback Machine).
Simple ordering, pay by PayPal. All your basic needs... adapters, sensors... either as components, or made up on RJ-11 / RJ-45 cables. Some interesting "convenience" connectors and PCBs.
The site offers good general information about 1-Wire installations.
There is a long reliable humidity sensor module based on Honeywell HIH-4031 sensor, in addition to several variations on ways to connect temperature sensors.
Please note: Sheepwalk Electronics and SheepdogSoftware are unrelated... we both adopted our names long ago (SheepWalk Electronics is a diversification of a different SheepWalk enterprise), and independently. (SheepdogSoftware and SheepdogGuides are related, and are the source of the page you are currently reading.)
PCSensor.com/ RDing Tech Company Limited, Hong Kong: This firm seems to have been around since at least 2009, but it wasn't yet doing 1-Wire back then.
I bought one of their temperature monitoring products in February 2011, and when in August 2011 I finally got around to trying it out, I was so impressed that I wrote a separate page about PCSensor.com and its offerings. They have 1-Wire relays, humidity sensors, data loggers in a "thumbdrive" format... standalone. Etc! They have a device ($60, Sept 11) that takes 1-Wire sensors on one "side" and connects to Ethernet on the other.
While I am a fan of this supplier, with regret I must bring something to your attention. Through an unfortunate mistake, they managed to release some components wired for one standard, and others wired for a different standard... all on the same 3.5mm plug-and-socket connectors! If you place more than one order with them, be careful. Happily, it is just a matter of using an adapter, if you have a mix of connector "standards". I've written a page about dealing with the PCSensor connections mix-up.
PS: December 2013: I pretty well gave up using PCSensor a while ago, after becoming frustrated with their customer "support". At their website, they were saying they would send the "fix our problem" adapters to customers. Requested adapters... no response. I also made suggestions about how they might make their "English" website more readable. Website remained unclear. A pity. The engineering department... if you can forgive the "little boo-boo" over the connector standard... impressed me. Marketing... not so good.
Note for suppliers: I'll be quite happy to edit any of the above entries, to correct errors, or to mention new products. In submitting suggestions, you should know that I intend for the page to remain focused: Lots of facts, no graphics, little market speak. If you write please include prices, information on how long you've been selling 1-Wire stuff, and tell me if you accept PayPal. Please cite the URL of the page you want edited. (E.g., for this page: "www.arunet.co.uk/tkboyd/e1dhw.htm")
Page tested for compliance with INDUSTRY (not MS-only) standards, using the free, publicly accessible validator at validator.w3.org. Mostly passes.
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