iButton FAQs

A quick rule of thumb is if you are developing for Windows then you need the 1-Wire SDK for Windows. If you are doing Java development then you need the 1-Wire API for Java Kit. We also provide a nice, highly-portable API developed in C for other platforms (including microprocessors). See link below for a web page that lists our 1-Wire and iButton Software Development Kits (SDKs).

Also, see the link to Application Note 155. It explains in detail each API and the 1-Wire devices that are supported.
1-Wire SDK for Windows
Application Note 155

Yes. See links below. The OneWireViewer is a general demonstration program that comes bundled with the 1-Wire Drivers (that install the drivers necessary to communicate to 1-Wire PC adapters). We provide APPLICATION NOTE 4373:
OneWireViewer and iButton Quick Start Guide
OneWireViewer and iButton Quick Start Guide
1-Wire Drivers

All of the examples are provided with complete source code. The only exceptions to this are some 1-Wire Windows drivers that are released as binaries only. However, they can be distributed freely however.

All of the software examples are distributed under a ‘public domain’ style license located
here

. It is based almost word for word on the
Xfree86 license
. Developers are free to use and integrate the code into their applications without restriction.

Yes.

Maxim has implemented a nice coporate-wide support request system where a customer can contact iButton and 1-Wire application engineers directly.
Maxim Support Center

The old parallel-port-only Software Authorization Hardware Kit has been discontinued as a kit. However, it has been replaced with a newer software that interacts with the SHA-1 secure iButtons. See the link below.
Software Authorization Kit

Make sure that your web browser is set to perform anonymous FTPs. Try the download again at a different time of day to eliminate network congestion as the source of the problem. If you still cannot download it, then open a support request about the Maxim website through the Maxim Support Center.
Maxim Support Center

Take a look at our software resources web page. It contains links to all of our iButton and 1-Wire software except for the code that requires a non-disclosure agreement. Check back to the specific software resource that you are using or developing with to see what updates (if any) have occurred. Also, you can check with the application engineers at Maxim through the support center to see if any updates are in the pipeline.
Software Resources Web Page
Maxim Support Center

Maxim has partnered with many companies we define as Authorized Solutions Developers, or ASDs. These companies can provide 1-Wire / iButton commercial products and custom solutions. Please visit our on-line look-up search engine to find the ASD with the experience you need, the product you wish to purchase, or the ASD that is simply closest to you.
ASD Solutions Providers

Take a look at our software resources web page. It contains links to all of our iButton and 1-Wire software except for the code that requires a non-disclosure agreement. Check back to the specific software resource that you are using or developing with to see what updates (if any) have occurred. Also, you can check with the application engineers at Maxim through the support center to see if any updates are in the pipeline.
Software Resources Web Page
Maxim Support Center

Take a look at our software resources web page. It contains links to all of our iButton and 1-Wire software except for the code that requires a non-disclosure agreement. Check back to the specific software resource that you are using or developing with to see what updates (if any) have occurred. Also, you can check with the application engineers at Maxim through the support center to see if any updates are in the pipeline.
Software Resources Web Page
Maxim Support Center

Take a look at our software resources web page. It contains links to all of our iButton and 1-Wire software except for the code that requires a non-disclosure agreement. Check back to the specific software resource that you are using or developing with to see what updates (if any) have occurred. Also, you can check with the application engineers at Maxim through the support center to see if any updates are in the pipeline.
Software Resources Web Page
Maxim Support Center

Take a look at our software resources web page. It contains links to all of our iButton and 1-Wire software except for the code that requires a non-disclosure agreement. Check back to the specific software resource that you are using or developing with to see what updates (if any) have occurred. Also, you can check with the application engineers at Maxim through the support center to see if any updates are in the pipeline.
Software Resources Web Page
Maxim Support Center

Take a look at our software resources web page. It contains links to all of our iButton and 1-Wire software except for the code that requires a non-disclosure agreement. Check back to the specific software resource that you are using or developing with to see what updates (if any) have occurred. Also, you can check with the application engineers at Maxim through the support center to see if any updates are in the pipeline.
Software Resources Web Page
Maxim Support Center

Take a look at our software resources web page. It contains links to all of our iButton and 1-Wire software except for the code that requires a non-disclosure agreement. Check back to the specific software resource that you are using or developing with to see what updates (if any) have occurred. Also, you can check with the application engineers at Maxim through the support center to see if any updates are in the pipeline.
Software Resources Web Page
Maxim Support Center

The iButton can be mounted in a key fob that can be put on a keyring. There are three styles of key fob. It is recommended that the F5 type can be used with the Dallas fobs.

There are some other companies that have key fobs available for the iButton.
Dallas key fobs
Other key fobs

The iButton can be mounted in a key fob that can be put on a keyring. There are three styles of key fob. It is recommended that the F5 type can be used with the Dallas fobs.

There are some other companies that have key fobs available for the iButton.
Dallas key fobs
Other key fobs

The mating plug is a Molex Part Number 22-04-1041. This is a PCB mounted connector.

No, the standard is a green LED. But the LED can be easily changed to another color.

No, but we have information about companies that do. These companies are part of the iButton Solutions program.
iButton Solutions search

Although the OneWireViewer can exercise many of the feature of the DS1923, it does not implement the two compensation algorithms located on page 53 of the DS1923 datasheet. Specifically, it does not correct for "RH Temperature Compensation" and "Software Saturation Drift Compensation".

Because of this, we recommend the "Hygrochron Viewer" as the demonstration program of choice for the DS1923.
1-Wire SDK for Windows

The Hygrochron Viewer requires J# Redistributable Package in order to function. Click on the URL below and choose the correct version for your architecture (32-bit or 64-bit). Then, download and install the redistributable.

After this installation is complete install the Hygrochron Viewer.

1) If you haven't already, download and install the 1-Wire Drivers (see link below).

2) Download the 1-Wire SDK for Windows (see link below).

3) Open the 1-Wire SDK's zip file and navigate to here:

Examples/OW.NET/C#/bin

4) On your PC make a directory from where you would like to launch HygrochronViewer (for example, call it "HygroView").

5) Copy/Extract the files inside the zip file in Examples/OW.NET/C#/bin to your new directory.

6) Launch HygrochronViewer by double-clicking the executable.
Visual J# 2.0 (second edition) Redistributable Package for .NET
1-Wire Drivers
1-Wire SDK for Windows

Our iButton Solution Providers, provide starter kits for the DS1923. Embedded Data Systems is one such provider offering DS1923 starter kits. See the link below for details.

Maxim does not currently manufacture a starter kit for the DS1923. However, that said, you could purchase the Thermochron Starter Kit, DS1921K. While it does not contain a DS1923, the kit can be used with any iButton. The kit contains a USB Port adapter, a "Blue Dot" cable, and a DS1921G Thermochron. Purchasing this kit, along with a DS1923 will work as a "Starter Kit".


DS1921K
Embedded Data Systems

Our dataloggers are factory programmed to meet the accuracy specifications as defined in their corresponding data sheet for each product family. All device parameters (including the temperature accuracy) are guaranteed for 1 year under Maxim standard terms and conditions with the condition they have been properly handled and used within all operating condition ranges specified in the datasheet.

Our temperature data loggers determine the current temperature by measuring the inherent physical properties of their onboard integrated circuits. Due to this technique, we generally know of no physical mechanism to cause our temperature data loggers to go out of calibration over the lifetime of the part except by exhaustion of the internal lithium power source to the point the part is no longer functional. Exhaustion of the internal lithium battery is caused by age, temperature, and sampling rate(s). Our datasheets show detailed plots of expected device lifetime based on time, temperature, and sampling rate(s).

Our humidity logger measures %RH using a standard humidity sensor. Therefore, it will need to be recalibrated periodically depending on the environment it is operating in since absorption of contaminants can degrade its accuracy.

If you are concerned or you have regulatory requirements regarding accuracy, then we recommend you work with a third party to perform recertification and/or software recalibration of your data loggers.
Maxim Standard Terms and Conditions
Calibration Services

The DS1923 is water-resistant but not considered waterproof. If you plan to place the DS1923 in an outdoor environment then it is recommended to protect the DS1923 from any type of water immersion or exposure to heavy rains. The document below explains the ingress protections of the DS1923 to have a rating of IP56.







Understanding the IP Ratings of iButton Data Loggers

See the Application Note below with the same title.
http://www.maximintegrated.com/appnotes.cfm/an_pk/3808

The iButton is a slave device and requires a master to initiate communication to it. A master can be a PC or a micro processor. With the master constantly polling the iButtons, communication to iButtons can be started by a simple touch to a 1-Wire interface called a Blue Dot Receptor. Every iButton has a unique 64-bit serial number, which gives it a unique 1-Wire network address.

The iButton is ideal for any application where information needs to travel with a person or object. This includes point-of-sale transactions, remote access authorization, data logging (including time/temperature/humidity), maintenance and quality control. Because every iButton communicates a unique serial number, iButtons are always addressable and able to be located on a network.

Information is transferred between the iButton and host with a momentary contact.

Click here to see
iButton Applications
from around the world.

Thanks to sealed stainless steel, you can drop it, step on it, or scratch it. The iButton is wear-tested for 10-year durability and a million hot contacts.

You need four things to work with iButtons:
1. iButtons.
2. A host system -- a PC, a laptop, or a hand-held computer.
3. A
1-Wire Adapter
and
iButton Probe
to get information into and out of the button.
4. Software (links below)
1-Wire for Windows (TMEX)
1-Wire Public Domain Kit
1-Wire API for Java

Nearly 2 million public transit passengers in Istanbul carry their iButton on a plastic key fob. It's the simplest way to mount an iButton for applications that require only momentary contact. After snapping in the iButton, the fob can be attached to a key ring. Fob types vary to fit the depth of the iButton they will carry and offer the choice of angled or straight shapes.
iButton Fobs

Check out the Mounting Options in our Product Section to find what you need. You will find a versatile assortment of mounts, lock rings, flanges and adhesive pads. Also, our partners have designed several different options for your consideration.
iButton Mounting Options
Partner Mounting Products

We have created the 1-Wire API for Java. With this, a programmer can write a simple Java applet. Keep in mind that it must be digitally signed. Contact the Automatic Information BU and request the source to an example signed applet.
http://support.maxim-ic.com/ibutton

When a copy of a software application is purchased, the company that developed the software sends an iButton (and a DS9490B USB iButton holder) with the software. For the end-user to invoke the application, an iButton must be present and supply the program with valid information in order for it to operate. This way, many copies of the program can be made, but only those invoked with valid iButtons will function. For more information, see the link below.
1-Wire Software Authorization Kit

All of them! All iButtons have a unique serial number that TMEX can search for and find. Also, the current memory-based iButtons are supported with a file system in TMEX. Since TMEX includes all of the basic 1-Wire communication functions, it is compatible with all current and future iButton products.
1-Wire Drivers for Windows (TMEX)

iButton developers are found all over the world. See the Solutions Search to search by developer product, name or location.
Search by Product Needs
Search by Developer Name
Search by Location

The ROM ID number is a unique ROM code that is 64 bits long. This number is factory lasered into each 1-Wire device. This assures absolute traceability because no two parts have the same number. The first 8 bits are a 1-Wire family code. The next 48 bits are a unique serial number. The last 8 bits are the CRC of the first 56 bits.

Yes, however there are some delivery restrictions, NRE costs, and minimum quantities to purchase that vary depending on the part, so please contact Maxim at the URL below for complete details.
http://support.maxim-ic.com/1-wire

No, only the customer that has set up the Custom ROM part has the right to buy it. This can act as a protective device to prevent reverse engineering or copying of a product

The only difference between the F3 and F5 is the height of the can. The F3 is 3.10mm and the F5 is 5.89mm.
If humans are going to be interfacing with the iButton (picking it up), the F5 can is easier to handle.

Yes, due to the unique ROM ID number in each iButton, a number of iButtons can be on the same 1-Wire line and each can be addressed individually.

The iButtons are very resistance to ESD. Some are rated up to 27KV. Most are good to at least 8KV. So little, if any, extra protection is needed for the iButtons.

The recalibration statement is a disclaimer. The sensor is exposed and it is possible for customers to use the DS1923 in a contaminated, dirty, polluted, etc environment. If that happened, the sensor would drift away from calibration due to contamination. Depending upon the environment, it might need recalibration after a short period. Since we have no control over this, we want to alert people that the accuracy could change.

Maxim does not make a fob for the F3 can, but there is a list of companies that do make fobs. Some of them will work with the F3 fob and some of the fobs can be customized with company information
Fobs company list

Maxim is in the process of making all the iButtons RoHS compliant. In an effort to keep our customers informed as to the status of this conversion, there is a website that allows customers to lookup their iButton part number to see if the RoHS part is available.
Lookup Lead-Free/RoHS Products and Content Data

The iButton metal "can" is Type 305 Stainless Steel and the insulating grommet is molded from a polypropylene homopolymer resin that has a carbon black additive to inhibit breakdown due to ultraviolet light.

Yes, it is possible to get the iButton with custom branding. Contact the Applications Department at the URL below.
http://support.maxim-ic.com/ibutton

The Thermochron is a single-chip digital thermometer, thermostat, clock, calendar and data logging memory housed in the stainless steel iButton. It is battery-powered and physically able to endure the most challenging environments. See the link below for a table showing the entire iButton line of data loggers.
Thermochron Overview
Entire Line of Data Loggers

You can use the Thermochron anywhere you want to monitor temperatures. Extremely durable and only 16mm in diameter, the Thermochron is ideally suited for remote and/or mobile thermal tracking in refrigeration units, trucks, crates, and incubators for purposes of chemical, food or other organic material storage, maintenance and transportation. It can be attached to bottles, such as thermally sensitive chemicals, or mounted on walls. For waterproofing applications, see the DS9107 iButton Capsule.
DS9107 iButton Capsule
Third-party waterproofing

The Thermochron lifespan is dependent upon usage conditions, specifically, how often the device samples, what environmental conditions (temperature) to which the iButton is exposed, etc. See the lifetime/lifespan graphs located in the Thermochron datasheets for lifetime expectancies based on usage conditions.
All Data Loggers

Please see Application Note titled: "Guidelines for Reliable Long Line 1-Wire
Application Note 148

You can multi-drop the Thermochron just like other iButtons and 1-Wire devices. Other probes besides the Blue Dots can be found on the following pages.
Other Probes
Other Partner Options

You can check the register that records the total number of conversions over the lifetime of the Thermochron. This register serves as a "gas gauge" because the primary consumer of lithium power is the temperature conversion circuitry. The conversion process uses lithium even if the chip's other "front end" functions are externally powered.

See the lifetime graphs in the device's datasheet.

Finally, if you have a DS1922/DS1923 data logger, Maxim provides an application note on the topic.
All Data Logger Datasheets
DS1922/DS1923 Battery Gas Gauge

iButtons are not guaranteed waterproof and require a watertight enclosure if they will be immersed in any type of liquid. Maxim offers the DS9107 iButton capsule as a solution for protecting iButton temperature loggers from liquids. Although the iButtons are not waterproof, they are water resistant and certified to IP56 standards.
DS9107 iButton Capsule
Waterproof Loggers & Enclosures
Thermochons are IP56 Rated (water resistant but not waterproof)

Temperature ranges for all data loggers can be found in the table on this
page
.

Operating any logger above or below its thermal operating range can damage its internal battery or components.

If the logger records data while in an environment above or below its thermal operating range, the recorded data collected will not go above or below the specified operating range. The logger will continue to operate at temperatures above or below its operating range for an unspecified time before stopping due to lack of battery power. Depending on the length of time that the logger is exposed to temperatures outside of its operating range, the logger may continue operating properly.

Storage or operation above 50C significantly reduces battery life.

See each loggers datasheet for expected life span at different temperatures.
All iButton Data Loggers

Maxim is the OEM manufacturer of iButtons and iButton data loggers. As such we mainly provide software development kits to third-party developers. That said, we do provide the OneWireViewer which is a Java demo application for exploring iButton or 1-Wire chip features from your PC. The OneWireViewer automatically finds iButtons or 1-Wire chips on the 1-Wire Network and displays their serial numbers with a description of relevant features and menu options.

For commercial-grade turnkey software, please see the link below.
OneWireViewer & Drivers
Software Development Kits & Examples
Commercial Software Providers

Linux code that interfaces with Thermochrons can be found in the 1-Wire Public Domain Kit.
1-Wire Public Domain Kit

Yes. The DS1921 family of Thermochrons are supported by the Java "container" OneWireContainer21. The DS1922 family of Thermochrons, along with the DS1923 Hygrochron are supported by OneWireContainer41. They are both available for download in the 1-Wire API for Java Software Development Kit (SDK).
1-Wire API for Java SDK

In order to preserve battery life between uses, it is recommended to disable the clock. From the OneWireViewer software, select the device from the OneWireViewer device list. On the right, click on the clock tab and depress the 'Halt Real-Time Clock' button.

By popular demand, this feature has been integrated into the OneWireViewer. Simply right-click the graph and the data log can be saved as a *.csv file which can be opened by most spreadsheet software.

There is also an Application Note that describes how to export the data from Thermochrons into an Excel spread sheet and graph the results. The Application Note is
App Note 3809
Exporting DS192x Logger Data from the OneWireViewer into Excel
.

We also have several partners with software products that will automatically download Thermochron data into an Excel spread sheet.
Partner Software Products

There are charts in the data sheets that show expected lifetime. Battery life is effected by temperature and the rate of sampling. The higher the temperature or the quicker the sample rate, the shorter the battery life.
All Data Logger Data Sheets

Yes, the hardware used with the DS1921 can be used with all types of the DS1922 and DS1923.

The iButton Viewer was retired and replaced by the OneWireViewer before the DS1922/23 data loggers were introduced. The OneWireViewer is also free for the download.
OneWireViewer Software

The answer is to fill in the Temperature Alarm points. Even if the alarm is not turned on, the alarm points must have a value filled in.

The Temperature tab is used in the Forced Conversion mode. This cannot be done when there is a mission in progress. Go to the Mission tab and use the Temperature tab to see the data from the Thermochron.

The length of time varies between the DS1921 and DS1922 loggers. The TempLoggerCalc application can be used to select the type of Thermochron and vary the sample rate to see the total length of time that will be logged.
TempLoggerCalc Application

Maxim does not recommend using the Thermochrons inside any living creature.

Our dataloggers are factory programmed to meet the accuracy specifications as defined in their corresponding data sheet for each product family. All device parameters (including the temperature accuracy) are guaranteed for 1 year under Maxim standard terms and conditions with the condition they have been properly handled and used within all operating condition ranges specified in the datasheet.

Our temperature data loggers determine the current temperature by measuring the inherent physical properties of their onboard integrated circuits. Due to this technique, we generally know of no physical mechanism to cause our temperature data loggers to go out of calibration over the lifetime of the part except by exhaustion of the internal lithium power source to the point the part is no longer functional. Exhaustion of the internal lithium battery is caused by age, temperature, and sampling rate(s). Our datasheets show detailed plots of expected device lifetime based on time, temperature, and sampling rate(s).

Our humidity logger measures %RH using a standard humidity sensor. Therefore, it will need to be recalibrated periodically depending on the environment it is operating in since absorption of contaminants can degrade its accuracy.

If you are concerned or you have regulatory requirements regarding accuracy, then we recommend you work with a third party to perform recertification and/or software recalibration of your data loggers

Maxim Standard Terms and Conditions
Calibration Services

Currently, only the DS1922L has NIST certificates available for free download.
Thermochron NIST Traceable Certificates

Enter the device name (i.e. DS2401) into the 'Part No. Search' text box of this web page (top right) and press enter. From the quick view page, click on the 'Technical Documents' tab. Scroll down to the reliability reports and open the PDF.

The ordering information on the web is correct for larger orders. Thermochrons have a small buffer stock that that is not reflected on the web and allows orders with less than 100 pieces to ship out quickly (usually less than a week).

Thermochrons can be missioned many times. The internal memory is overwritten when a new mission is setup. The device can be used until the internal battery is consumed. The battery is not rechargeable or replaceable.

The DS1920 is not a data logger, rather a temp sensor. The difference is a sensor requires a host PC or micro controller to interrogate the device for the temperature reading and stores the result in the host memory (Hard disk, etc.) and must therefore be connected to the device during the duration of the data collection. A data logger, once missioned (via PC software), does not require any other connections in order to take and store temperature readings. The data is stored in device's memory and extracted once the mission has completed.

Please follow the link below.
Device Certifications

Maxim no longer produces 1-Wire weather stations. For companies producing similar weather stations please see our
Solutions Search
.