Well, at the moment I do have some good results with the modified solarunit but I will try to make it a bit exactlier by using two light probes. One looking eastwards and one westwards. I have to experiment which solution is better.
But now I have enough to do to get my own server to work.
Regards
Jose
I guess it depends what you are trying to measure. If it’s Global Solar Radiation as used in WD’s calcualtions then you need one sensor, mounted horizontally, with a diffuser over it. OTOH if it’s a frog’s eye view of the sky then that two sensors at an angle design would be perfect 
David, I hope having some Easter free time to make it, I have everything I need but the time 
So would I.
Have a look here: http://discourse.weather-watch.com/p/305267
In the attachment you’ll find a photo. Replace the temp bead marked with a red X. Then connect your new config at the two pins marked with a curl.
Also there is the English manual for the light probe.
My “humidity board without a humidity sensor” shipped today - literally!
A feeling I know all too well.
If we have some fine weather over Easter maybe I’ll manage to get the cable duct buried?
This looks like a good project. I see I would need the THGR800 but what are you using for the solar sensor? And is it available online somewhere? I would love to add solar to my WMR100. Has anyone done this project and have it working?
Well, I don’t know exactly if it works with the WMR100 but why not.
The lightprobe I use I bought at www.conrad.de and is developed by “Hygrosens Instruments” http://www.hygrosens.com/english/home.html. This is a German company but I’m sure you’ll find this in the states or anywhere, too. Hygrosens would deliver to you I think but ask them for the costs. Well, Conrad also does international sendings but I think the delivery would be more expensive than the product.
Regards
Jose
Just thinking loud: Is light intensity directly comparable to solar global radiation? Does it match linearly?
I can probably find a sensor but need to know what the THGR800 is expecting for an input from the sensor…
Sorry, don’t understand your question. (not a native speaker 
)
Do you mean the value from the resistor? You can meassure it with an “Ohmmeter”.
Regards
Jose
That’s how I would answer too, it’s looking for a change in resistance.
Jose, if you have a multimeter can you measure the dark and full light resistance of that sensor you have?
Well I can do that but normaly it isn’t necessary. All the THGR worldwide should be the same. You need an 2,5kOhm resistor.
Regards
Jose
I was thinking it would help anyone who was looking for an alternative light sensor here in the US, those cells come in a wide range of resistances.
Well, I remember it was 102,5kOhm for dark and 2,5kOhm for light. It depends only on the THGR I think. Not on the light probe. I don’t know how expensive a light probe is outside Germany but I paid 10
That’s good enough. You can get cds cells for pennies http://www.goldmine-elec-products.com/products.asp?dept=1171 it’s the shipping that costs the $$ :lol:
OK. If you have any questions about that please fell free to ask.
After the next weekend I do have holidays and then I will try to make a manual in German and English how to do this modification.
Regards
Jose
I think I understand. The resistance in the circuit is changed by the amount of light the sensor detects.
I will get the THGR800 ordered. Niko, if you have a source for the sensor let me know.
The resistance in the circuit is changed by the amount of light the sensor detects.
Correct.
Ok, sounds good. Look forward to reading the manual.