1-Wire Weather Station

The 1-Wire weather station allows you to capture wind speed, wind direction and external temperature but it can be extended to include other functions. The good thing about this device is that it takes its required power from the 1-Wire network.

I have the new nersion (V3) of this device and it differs from earlier versions in that a DS2450 is now used to measure the wind direction.

Purchase

You can buy this device in the UK from Audon  but, I bought mine from a US-based company called Hobby Boards . I did this because I ordered many other parts with it. It is also cheaper but, be wary of shipping and customs costs.

Assembly

The latest assembly instructions (PDF) are for the older version of the board but are still largely true.

Testing

I used the One Wire Viewer  to test the basic operation. It found the following devices:
  • 9F00000000F43F20 (20 3F F4 00 00 00 00 9F) = DS2450
  • F10008001B4CD410 (10 D4 4C 1B 00 08 00 F1) = DS1920
  • E800000001097A1D (1D 7A 09 01 00 00 00 E8) = DS2423

Software

Rather than use existing software (of which there is plenty), I wanted to write my own in Java as part of my larger Home Control System. This proved a little harder than expected but I eventually found code samples that showed me what I needed to do. My software logs changes in the various values, rather than a continual stream of poll data.

DS1920 - Temperature Sensor

See the my 1-Wire temperature sensor.

DS2423 - Wind Speed

This is a bit harder to write Java code for. Although I understand how it works the calibration was an unknown. In the end I based my code on the TAI8515 Java class source code from the AAG Electronica download area . This example measures the counter changes over a 1 second period and determines the wind speed from this. You could get more accuracy by increasing the period but it will be less sensitive to gusts of wind as these will get averaged out. My software captures wind in miles per hour to one decimal place (e.g. 5.1 mph) and only logs changes in wind speed. This is primarily to avoid a huge log file full of zero values but it also means I can sample the wind speed at much higher intervals than would be normally done.

DS2450 / DS2401 - Wind Direction

The DS2450 is only used in the later version (V3) of the 1-Wire Weather Station. It replaces a DS2407 addressable switch. I copied code from the TAI8515 Java class source code from the AAG Electronica download area .

Again, I'm only logging changes in wind direction but sampling it fairly frequently.

Data Display

The Home Control System displays a synopsis of the logged data but this is text based. See the HCS graphs page for an overview of the graphical presentations.

Reference