Second attempt

[John O]

Hi All,

After my first useless attempt at shielding my temperature and humidity sensors from the weather, I've had a second try!

http://vwlowen.co.uk/picaxe/stevenson-screen/stevenson-screen.htm

John.

 

[Andrew Cowan]

Very nice, very profesional looking. Do you know how insect proof it is?

 

[cdngunner]

up here we have residual bug spray. Apply it once kills for month....

Atta-boy. Looks better then the pvc pipe

 

[John O]

up here we have residual bug spray. Apply it once kills for month....

Atta-boy. Looks better then the pvc pipe

Yeah it certainly does Thanks.

I suspect it will quickly become a home for the spiders but we can only wait and see. I use some anti-spider spray http://www.spiderex.co.uk/ for around my CCTV cameras so, hopefully, that should help.

John.

 

[John West]

I didn't read about your previous efforts on this, but I'll toss in my bit nonetheless, in case you hadn't already researched it.
For the most accurate accurate readings it's best to place the sensors several feet away from buildings and at a height of 8 to 10 feet above ground.

 

[John O]

Unfortunately, there's probably going to have to be a bit of a compromise with the positioning. I need to experiment with how long cable runs can be. I suspect the temperature will be ok but the analogue signal from the humidity sensor will lose a lot of accuracy and/or resolution. It all depends on where I can mount the wind and rain sensors and I haven't even started on the mechanics for those yet

I've got quite a bit of time before I need to decide the final position. The whole project is still in bits an pieces on the breadboard or "somewhere" between here and Futurelec. (I've had this thread bookmarked for what feels like an eternity ).

My 3 free magnets have just arrived from Austria. Five that I paid for a day earlier from a company about 50 miles down the road from me are yet to arrive! I'm having the magnetic SMD chip soldered onto a breakout board by a small company in Scotland so it's becoming quite an "international" project this

(Have you guessed what it is yet!!!)


John.

 

[Hugh McCormack]

Unfortunately, there's probably going to have to be a bit of a compromise with the positioning. I need to experiment with how long cable runs can be. I suspect the temperature will be ok but the analogue signal from the humidity sensor will lose a lot of accuracy and/or resolution. It all depends on where I can mount the wind and rain sensors and I haven't even started on the mechanics for those yet

John,

I spent most of my time in University operating the Geography Department's climate and weather station so I am well familiar with the Stevenson Screen. A word of advice for positioning the box so that you get accurate readings. Our Weather Office standards have the door facing North so that the sun cannot shine directly on the instruments. There are also standards for installing wind and rain gauges. If you need them I can dig them out of my "archives".

Cheers,

Hugh
Woody Point, NL

 

[geoff07]

If you have a problem with sending analogue levels over long distances, why not decode into a local 08M and send the data by serial? It is very simple to do, and if you added a 433MHz tx and a small solar cell and battery you could make the box wireless and send all the signals. As long as you only send data when it changed and have the chip sleep most of the time you would not need much juice.

 

[John O]

Hugh: Luckily(-sort of), the temperature sensor will be near a north-facing wall which doesn't get any direct sun to speak of until near sunset so I'm hoping that'll be ok. The main downside is that it's going to have to be reasonably close to the wall (about 10" at best). I'll be relying on the almost perpetual breeze to keep the air changing. The humidity sensor seems to climb to well into the high 90's too easily anyway so I'm not convinced it's a very meaningful reading (that's with the "full blown" Peter Anderson code).

geoff07: Serial is a good idea. I'll have to give that some thought. The main outdoor box will have all the outdoor sensors feeding into it and it will have a 433 MHz wireless transmitter to the indoor box which will house an LCD display and a pressure sensor (if it ever arrives!). Two transmitters may cause a problem unless I synchronize them.

The wireless is on trial at the moment (with the Picaxe "Manchester coding " chips) and, so far, I've had about 6 days out of a fully charged 7AH 12 volt lead acid battery with the transmitter sending every second. So I'm hopeful a solar panel will keep it charged - eventually - if I drop it down to about once every 30 seconds.

If I'm careful about screening, there's no reason that I couldn't power the remote temperature/humidity Picaxe along the serial cable that's sending the data back...

All good fun and plenty of options

John.