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What is 1-wire®?
Description
The 1-Wire network protocol was developed by Dallas Semiconductor(now Maxim) as a way to interface to range of small devices, such as digital switches, sensors and analogue-to-digital converters to a PC or microprocessor. Every 1-Wire device contains a unique identifier preset at the factory. As the name suggests, the devices are networked together by a single wire that acts as a physical medium to communicate between a host and a large number of devices attached along the wire. It is also capable of powering these devices through the same wire. In practice, a second wire is actually needed to provide a return to ground and complete the circuit and most 1-wire units actually use a 4-wire RJ11 cable.
1-wire devices are based around a range of 1-wire IC's available from Dallas Semiconductor. Dallas offer several different types of devices from temperature sensors, pulse counters, memory devices and battery monitors. Some IC's can be used for purposes other than that originally intended. For example, the DS2450 quad analogue input chip is used in our 1-wire weather station kit to determine wind direction!
Dallas devices and their potential uses: Dallas Device Our Part Possible Uses DS1820 TAI8520 Temperature measurements over room temperature range DS2438 TAI2438 General Purpose Analogue input - Humidity, Pressure, Light, etc - any single channel voltage input DS2760 TAI8560 Battery monitor - can be used for low-lovel voltage nmeasurements such as thermocouple, pH measurements etc DS2423 TAI8586 Dual counter inputs - used for counting pulses - wind speed, rain gauge, flow meters, electricity meters, gas meters, water meters, people counting DS2450 Under development 4-channel 16-bit analogue input - general voltage measurements DS2406 TAI8555 Dual digital output - can be used to switch relays, lights, alarms etc DS2408 TAI8558 8-Channel digital I/O DS2890 Under development single potentiometer output - volume control, analogue output, 4-20mA loops etc The 1-wire protocol was origonally concieved for short range circuit-board uses, but it was soon discovered that the system was ideal for connecting 10's of devices over 10's of meters. It is even possible to have over 200 devices spread over 100's of meters, but some precautions need to be taken. Maxim have written an application note describing this. There is also an application note for building ultra-reliable networks. A 1-wire network (also known as a microLAN) needs some kind of Master. This is inveriably a PC either running Windows, Linux or other operating system, but can be a microprocessor or a dedicated 1-wire datalogger. There are RS232 (DS9097U), USB (DS9490R) and even Ethernet adaptors to connect the 1-wire network to a PC. For reliable long-range 1-wire networks, the Link RS232 adatpor is reccommended.
Products
Weather Interfaces Datalogger Modules
Typical Applications
Weather Monitoring >> Temperature/Humidity Monitoring >> Water/Gas/electricity Metering pulse counting >>
1-wire Software
Software Development kits >> 1-wire Public Domain Kit - A public domain API written in C and designed to be portable across multiple PC operating systems, handheld operating systems, and microcontroller platforms. The kit contains 18 sample 1-Wire applications written in C. For microcontroller platforms without an available C compiler, the kit also includes assembly code functions representing low level 1-Wire bus protocol algorithms such as reset/presence detect, byte I/O, and bit I/O.
1-wire SDK for Windows - This SDK is aimed primarily at PC host environments running Microsoft Windows. Both the 1-Wire drivers and SDK for Windows are available for downloading. The kit contains sample programs (in VB, C, Delphi, JScript, etc.) and HTML documentation for utilizing the TMEX API and the 1-Wire COM object. The 1-Wire drivers download contains optional support for Microsoft's .NET platform The OneWireViewer utility is also offered to demonstrate 1-Wire devices. 1-wire API for Java - The 1-Wire API for Java is the foundation for developing robust 1-Wire and iButton software on platforms that have a Java Virtual Machine. It includes the above-mentioned OneWireViewer utility and its Java source code		Sample shots from the 1-wire Viewer
Recommended FREE 1-wire Software Applications
LogTemp - Temp/Humidity Charting and Logging Logs and charts Temperature and Humidity Service version also available - no user log-in required Can launch programs and email alerts on alarm Also supports SMS Text via Commercial gateway Access via HTML, FTP, email For use with TAI8520 and TAI8540 Now with counter support - TAI8586 More Info and FREE Download >>
Thermometer - Temperature Charting and Logging Logs and charts Temperature High and Low Alarm facility Chart, LCD and dial gauge displays User graphic screens with temperature overlay For use with TAI8520 More Info and FREE Download >>
Roso DDE Software Supports most 1-wire Devices Has window viewer Single and Multi-channel chart display DDE server for real-time data transfer to Excel etc More Info and FREE Download >>
DigiTEMP - Linux based Temp Charting and Logging Supports most 1-wire Devices For use with Linux Charts and Logs data More Info and FREE Download >>
DOWeather for the PalmOS DOWeather (pronounced DOW Weather) is a PalmOS application for displaying current weather data from a 1-wire Weather Station, creating a truly portable weather instrumentation system. The new version 2.0 adds colour and supports the new version 3 weather station, and can search for the primary 1-wire devices. It also supports the DalSemi Humidity Sensor and adds several new features. Requires PalmOS Version 3.1 or greater. Uses the Palm serial port and requires a DS9097U Serial Port Adapter and a custom built powered null-modem cable (instructions included) More Info and Downloads >>
Weather Software for the Apple MAC MacWeather is a simple MacOS example console application that works with the WS-1 to display the weather information. It was written in 'c' using CodeWarrior version 6, and is based on DalSemi's public domain code. It is intended to provide Mac Developers with a basis for a full-blown weather station program. The current version runs and displays weather data, but does not have a user interface. The source code & application supports a version 1 or version 3 weather station. It also supports the DalSemi Humidity Sensor, Rain Gauge, and the 1-wire lightning monitor. Data can be posted to the internet using the Mac OS 9's built-in Web Sharing. A new Java weather server, based on the TiniWeatherServer will available soon. It is designed for Mac OS X users and supports USB to Serial adapters. It will run in the background collecting weather data and serving web pages. More Info and Downloads from Tim's Weather Projects Pages >>
LabVIEW 1-wire Weather Drivers LabVIEW drivers for the 1-Wire Weather Station including standalone drivers for the DS1820 1-Wire temperature sensor and DS2423 1-Wire counter. This download includes the DLL, all source code, example VIs, and the Visual C project. (LabVIEW 6, Windows 32-bit DLL, DS9097U 1-Wire serial adapter required, does not use TMEX) LabVIEW Weather >>
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