Weather station hardware

Basic weather station

Support table for known 1-wire wind vane / anemometer units

Dallas Original weather station Working
AAG Version 2 weather station Working
AAG Version 3 weather station Working
AAG WSI603A Working
Hobby Boards Anemometer ADS Provisionally working
Hobby Boards Anemometer Inspeed Not supported

Weather Station
1-wire weather station on test


There was also a ‘tipping bucket’ rain gauge available from Dallas. Made of a sturdy plastic moulding, this can attach to a mast. However, this is no longer available; but AAG have conversion kits for the non-one-wire Davis rain gauge.



For a while Dallas had a kit for a relative humidity sensor. This was discontinued, but you can build one yourself, based on information from Dallas.

AAG have two different forms of their TAI8540 module.

The H3-R1-A humidity board is available from Hobby Boards in kit form or assembled. Please note that solar/humidity variants from Hobby Boards may only be assigned to Oww as either a humidity sensor or a solar sensor – not both.

From version 0.81.6 Oww support the DS1923 hygrochron iButton, in forced conversion mode (i.e. live data, not missions).

Solar Radiation

Solar detector

The old Dallas kit could also be built up as a solar radiation monitor.

The S3-R1-A solar radiation detector is available from Hobby Boards in kit form or assembled. Please note that solar/humidity variants from Hobby Boards may only be assigned to Oww as either a humidity sensor or a solar sensor – not both.

UV Index

UVI board

The UVI2-R1-A UV Index Meter is available from Hobby Boards .

Barometric pressure

Oww can read from AAG TAI-8570 barometers.

  • Supplied pre-calibrated - the only setup required is to account for your station altitude
  • Pressure range 300 to 1100 mBar
  • Can be powered parasitically

Many thanks to AAG for supplying a sample TAI-8570.


Oww can also read barometric pressure from DS2438-based barometers. Various do-it-yourself designs have been developed. Follow these links for more information:

Simon Atkin
David Bray
Philip Gladstone
Andrew Miller

Many thanks to Simon Atkin for donating a built barometer module (pictured to the right).

The BB4-R3 Bray Barometer is available from Hobby Boards in kit form or assembled.


General-Purpose Counters

The anemometer and rain gauge both count events (cup rotations or bucket tips) using a counter chip. Oww can read from extra “general purpose” counters as well. One example of a possible use is a lightning detector.

The DC2-R1 dual counter board is available from Hobby Boards in kit form or assembled.

The LD3-R2 lightning detector is available from Hobby Boards in kit form or assembled.


LCD interfaces based on the DS2408 parallel i/o chip may be addressed by Oww, to display weather data. Two types of interface are suuported (they use the two output nibbles differently):

Actually I don't have either of these myself. Instead I made myself a small PCB with headers for both configurations from their published schematics.

See also the iButton LinkHub, below.


Oww now supports DS2409-based “hubs”, as described by Simon Atkin at


1-Wire Adaptors

The computer running Oww has to communicate with the weather station devices on the 1-wire net, using a 1-wire net adaptor. Several types of adaptor are available, the most common of which are supported by Oww:

1-wire adaptors DS9490R iButton Link DS9097U
Maxim / Dallas DS9097U and DS9097U-E25 (not tested)
The DS9097U series adaptors are based on the DS2480 RS232 to 1-wire adaptor. They are supported by all versions of Oww.
iButton Link
The LINK is an RS232 to 1-wire adaptor, built around a micro-controller that emulates the behaviour of a DS2480. Its 1-wire interface is reckoned to be superior to the DS2480, making it especially suitable for long or complicated 1-wire networks. It is supported by all versions of Oww.
Maxim / Dallas DS9490R
The DS9490R is a USB to 1-wire adaptor, with an RJ11 1-wire connexion. There are also the DS9490B and older DS1490F adaptors, intended for iButtons, which may be adapted for connexion to a wired net.
Oww support for USB adaptors is as follows:
OS USB Supported? Notes
RISC OS No No support planned
Linux Yes See note about USB configuration
BSD Maybe Should work, but I've not succeeded yet
Eclo USB Adaptor
The Eclo USB Adaptor combines a DS2480 1-wire adaptor with an FTDI USB-serial converter. This means that, so long as the appropriate kernel module is loaded, it will appear as a normal serial port. For example, referring to the output of dmesg, my system assigns it to /dev/ttyUSB0, so I can set driver /dev/ttyUSB0 in the devices file. Note that a special ID is set on the FTDI chip, so that the kernel recognises it as an Eclo adaptor. This required a patch to the source for older versions of the kernel module. I don't think that has been included for the NSLU2 yet (?) but it is in main-line distributions such as OpenSuSE.
Eclo USB adaptor
iButtonLink LinkHub
The LinkHub is an RS232 to 1-wire adaptor similar to the Link. However, it provides four 1-wire buses, like a hub. Although these are electrically separate buses, logically they are seen as a single bus. Oww will therefore not show any extra hub DS2409 switch devices when a LinkHub is connected. Further DS2409-based hubs may be cascaded off the LinkHub.
I have run the LinkHub from my Linux PC with no problems. However, there may be compatibility issues between some hardware and LinkHub firmware releases. This is being investigated. Reports would be very welcome.
iButton LinkHub
The iButtonLink LinkHub
The LinkUSB is a USB to 1-wire adaptor similar to the Link, but interfaced through USB.
The iButtonLink LinkUSB

AAG WSI603B 1-wire Adaptor

The WSI603B does now work under Linux, but you have to be careful with your kernel driver.

It is based on the Silicon Labs CP2101 USB-to-serial adaptor. Previously this was not very well supported under Linux. However, if your distribution uses a recent version of the CP210x driver, rather then the older driver supplied by Silicon Labs, you should be Ok. I run openSUSE, and version 11.3 is now running cp210x v0.09, which I can confirm works with the WSI603B.

The adaptor is most convenient to use with the new AAG weather station, as it uses the new RJ45 pinout AAG adopted, and supplies power sourced from an external 12V supply. There are two 1-wire RJ45 sockets, so for example you may use one cable to your wind head, and another to a local sensor, such as a barometer. The internal opto-isolation will make me slightly less nervous when lightning comes by.

Computer Hardware

As well as full-blown computers running Linux/BSD or RISC OS, I now have Oww running on the Linksys NSLU2 network storage unit, or Slug. This is an XScale-based unit, running Linux, intended to provide a home server to Windows machines, by using Samba. There is a group of hackers at who have greatly expanded its functionality. It is equiped with two USB ports. I'm using one for a USB2 external hard disk (in principle it could work with just a USB flash drive instead) and the other for a DS9490R 1-wire adaptor. I have owwnogui logging to the disk, and uploading to Weather Underground.

Some advantages of using this device over a normal PC are:

  • Silent operation (just the hard disk)
  • Low power
  • Inexpensive (worth considering, especially in view of lightning damage)

You will need to follow the instructions on the Web site to convert your slug to unslung. Then you should log in as root, and install the oww package:

ipkg install oww

Start off with owwnogui in interactive mode, so that you can assign the devices:

owwnogui -i

You will need to use the interactive commands a to select the adaptor port to use, as the default /dev/ttyS0( isn't present on the Slug. Instead, you will want to choose either a USB serial port connected to a DS9097 (or similar) or a DS9490 USB 1-wire adaptor.

USB Serial Port and DS9097

To add a USB serial adaptor to the slug you'll need to install some extra kernel module packages. To find out which, under Linux look at the output of the dmesg command, it should give you some clues. Mine ends with "Prolific PL2303 USB to serial adaptor driver". Under Windows you can try looking at the Device Manager entry for the COM port. Mine says "Prolific USB-to-Serial Comm Port". So clearly mine uses the Prolific chip! This is a common one.

Next you need to install the required kernel modules. You'll need to:

ipkg install kernel-module-usbserial

Then you'll need to hardware-specific module:

ipkg install kernel-module-pl2303

Possible alternatives are

but there might be more.

For testing you can load these by hand:

insmod usbserial
insmod pl2303

The module should then claim the port (dmesg reports ...PL-2303 converter now attached to ttyUSB0...).

Now you can run owwnogui in interactive mode (owwnogui -i) and set the driver to the USB serial port:

devices driver /dev/ttyUSB0

Now carry on with the devices setup, below, but to make the modules load automatically at startup you will then need to create a script. I made /opt/etc/init.d/S79usbserial (it needs to have a name that comes before S80oww so that it runs first). The contents are just the insmod lines for your setup. Be sure to make the file executable (chmod a+xr /opt/etc/init.d/S79usbserial).

DS9490 USB-to-1-wire Adaptor

If you're using a DS9490 adaptor you just need to run owwnogui in interactive mode (owwnogui -i) and select the USB driver.

devices driver USB

The DS9490 can through up a few problems especially for an unslung NSLU2. My recommendation is to use version 0.82.1-1 in conjunction with libusb version 0.1.12-1. I have built a version of the old .ipk to host here as it has since been replaced on the normal feed. Since the difference between this the later version is a patch for digitemp, I presume that won't work with the old version. You may need to tell ipkg to remove any more up-to-date versions first, and then force a down-grade.

If you haven't bought your hardware yet I'd recommend avoiding the DS9490 and going with a serial-based adaptor instead. You can use one of the adaptors with USB-RS232 built in, but note that there's no suitable kernel module for the AAG WSI603B on unslung.


Next you can search for sensors and assign them to devices. Be sure to save your devices file at the end. Still in interactive mode, enter the following:

save devices

Chances are you'll need to reassign some sensors, as some of Oww's guesses will likely be wrong. Enter save devices again when the output makes sense. You can exit with the quit command.

Then run it in daemon mode with the init.d script (this will happen automatically at boot):


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