Bill - You never know how these things will turn out until the hardware arrives, but itās a nice little enclosure and very solid once the lid is on. Iām not sure I would trust it at the bottom of a swimming pool like one of the previous posters, but thatās more about the threaded gland rather than the enclosure itself.
Eric - I never intended to compete with the āweather geeksā just build something to survive the northern weather. There is a Davis VP2 a few miles from me, so should be able to get an idea of the accuracy. I am very limited as to placement of the solar shield, so this is likely to be the main factor.
I wrapped the sensor with thread seal tape called PTFE (teflon tape). So far so good since I half expected to destroy the sensor with the high humidity.
I had a few Doāh moments. My backyard has lots of bushes and flowers and trees. Not the best environment to get good readings. From what I have read since the sensor should be far away from plants, grass, & trees. And it should be mounted two meters above the ground. Mine was mounted on a 4 foot (1.2 meter) fence post in our garden - not good!
Here is a comparison between the emonTH in my backyard and the local airport readings. The temperature readings are fairly good (blue is the emonTH & yellow is the local airport). The humid readings are not so good (green is the emonTH and red is the airport).
www.aviationweather.gov
Click and drag the map to the area you want the ob data for, then click the METAR button on the toolbar near the top of the screen. Select the ob data you want to see by checking / unchecking the boxes just below the map. Zoom controls are in the upper left corner of the map.
http://mesowest.utah.edu/cgi-bin/droman/mesomap.cgi?state=IL&rawsflag=3
Hovering on a station - the black dots - pops up the ob data. Clicking and draging works the same as on the Aviaton Weather page. Zoom controls are in the lower right corner of the map. Ob data displayed on the map, and the source of that data, can be selected from the pull-down menus on the left side of the screen.
OEM node in yellow and blue, Wunderground data in red and green. Overall it compares pretty well, certainly close enough for me given the constrained mounting location.
Bill - forgot to tell you āthank youā for the two links. The mesowest link was the one that had the best info. I asked for the local NWS site because the data I get from Weather Underground (WU) is different. I started staring at the data when comparing WU data to my outside emonTH and noticed something odd. The WU temperature always increments/decrements by 1.8 degrees. It almost seems like WU is grabbing the NN:52 (8 minutes before the hour) METAR data and converting the temp from ĀŗC to ĀŗF. Not quite what I wanted!
Thanks Glyn Good tip there from @johncantor. I did chuck in a silica gel bag before final assembly to try and keep any moisture at bay, but some of that semi-setting potting compound is probably a good idea long term.
Whichever enclosure you use, do remember to drill a drain hole to the underside of the box. Unless hermetically sealed, condensation will surely accumulate.
just build something to survive the northern weather. There is a Davis VP2 a few miles from me, so should be able to get an idea of the accuracy. I am very limited as to placement of the solar shield, so this is likely to be the main factor.
