About LJ's Weather Station

Jul 2014: Have bought a Davis Daytime FARS kit #7745 (and a set of the standard radiation shields so I could build a full shield) and put the outside temp sensor in it in an attempt to bring the max daytime temp down to where it should be.

Feb 2011: The WMR928 sensors were starting to fail (especially the wind sensor), so given that you can't buy replacements any more, I've now got a shiny new Oregon WMR200 instead. Data is gathered by a modified version of wfrog and piped into my existing scripts and rendering of wx200d. The WMR200 adds a UV sensor and extra forecasts of "clear" and "snow" (yeay), but needs all new extra sensors to the WMR928 (at 30 a pop, boo!). I've modified the standard wfrog code based on observation and a very helpful write up of the WMR200 protocol here.

Old WMR928 details:
The instruments are in my back garden behind the shed ;)  They communicate at 433MHz with a WMR928 base station. (More details about the sensors here)  The base station connects via serial cable to my Debian Linux webserver.  I'm running a modified version of wx200d to log the data.

I've modified the wx200d daemon to work correctly with the WMR928 with the help of the output format of the WX200 weather station from here and the format of the WMR928 from here.  I also changed the daemon to log the forecast, total rain and light level data so they can be easily included on the summary and graph pages.

The light level is measured by a modified THC268 temperature sensor.  I chopped off the temperature sensor and connected a couple of LDRs and a resistor or two on a bit of breadboard instead.

The Max/Min/Total data is calculated every minute by a collection of shell scripts and pulled together with the latest readings into the summary page by a bit of Perl.



Updates...

Sunday 6th June '10

Cleaned the green slime out of the rain gauge. Eww.

Saturday 13th March '10

Moved the wind sensor out from behind the shed and away from the hedge that has been shielding it. It is windy round here!

Sunday 4th December '05

Bleh. Wondered why the rain chart has been plotting a nice curve recently.  The hole was blocked with some decaying bits of tree, so have cleared it out and moved the gauge to the other side of the shed away from the nearby trees.

Saturday 30th April '05

Recently bought a Davis Rain collector that samples in 0.2mm increments (rather than the 1mm of the Oregon).  Finally got round to making the code changes and butchered both rain colectors to fit the Oregon PCB inside the Davis unit.

Sunday 25th April '04

Moved the wind sensor about 8" higher.  Still not an ideal position (close to another house), but it's above the level of the shed now!

Now the evenings are sunny I think I need to shield the side of the temperature gauge - it catches the late evening sun.

Sunday 4th April '04

Still playing with colours - I've set the brightness of the backgrounds of the daily Sunshine cells to depend on the amount of sun that day.  The brightness of today's cell is also scaled by how far it is through the day, so lots of sun early on will get a bright background.

Friday 2nd April '04

Think I've just about settled on the layout of the new 'Sunshine' section - had to add lots of stylesheet stuff to get the cell borders to line up the way I want them to. (Think I've finally got the shell script right for the rotation to the previous days too ;P).  Coded the background of the Current Light Level cell to change with the light level.  Very cute ;PPP

Wednesday 28th Jan '04

Added another remote sensor - this time with the temperature sensor cut off and replaced with a 1" square bit of 0.1" stripboard.  I've soldered alternate tracks together.  Makes a nice dampness gauge :)

If the rain rate is 0 and the rainfall value is the same as two hours ago the summary line now includes 'damp' if the dampness is > 0 or 'very damp' if > 10.

Sunday 18th Jan '04

The temperatures recorded are too high during the sunny part of the day.  I'd mounted the instrument screen on a west-facing fence, now I've moved it round to the north side of the shed...

The 'Max' Light Level section on the summary page is looking a bit redundant.  Maybe 'hours of sunlight' or sunrise/sunset times would be more useful...

Friday 9th Jan '04

The light meter arrived, so I 'calibrated' the light sensor output.

Sunday 4th Jan '04

Moved the outside temperature/humidity sensor into a proper instrument screen.  Note to self: buy a ready painted one next time. ;)

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