UV sensor for WeatherDuino Pro2 weather station - Printable Version

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+--- Thread: UV sensor for WeatherDuino Pro2 weather station (/thread-101.html)

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RE: UV sensor for WeatherDuino Pro2 weather station - hornychz - 24-08-2016

(24-08-2016, 00:06)ctnxs1 Wrote:  What is the benefit of a JGS1 half ball hemispheres compared to a flat piece of JGS1? Do you get improved cosine response? Are you also using some kind of diffuser between the JGS1 and the UV sensor?

Hi ctnxs1,

Unfortunately, at this moment still can not answer ... (Whole summer, we had to "watch" a little granddaughter and I had no time to almost nothing. Now to catch up on my contracts, because my customers have everything they want to complete ...)

According to yet gained experience, but I think or know now:
- half ball hemisphere focuses light, perhaps too, probably would have been preferable hollow half ball hemisphere
- spherical curvature possibly eliminates cosine effect better than a flat plate with bevelled flanks ramp UVI measurement appears to be similar to the "official" measurement
- JGS1 has excellent UV transmittance around 92%
- light reflection is minimal
- hemispherical shape with virtually no pollute, the sensor is always squeaky clean

For these reasons, I find these filters for itself in perspective.

But, there are some problems:
- at this moment (all summer), I have not another instance CumulusMX to properly record the measured graphs (all the parts lying on my table)
- I've poorly glued (sealed) test filter, so I'm under it 2x allow water sensor, and then a few days did not measure
- test sensor is still in my garden on a table where the afternoon shadow, and I have not had time to put it on the roof

And even answer your question:
- no, there is no diffuser between the hemispherical JGS1 and sensor UVM30A

I am sorry that I have not progressed further, but that's just life ...

Regards

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RE: UV sensor for WeatherDuino Pro2 weather station - zitoune - 03-09-2016

Hello,

I initially built an enclosure for the UV/solar sensors with no specific protection: all sensors fully exposed to the elements.
The UV sensor was glued with Araldite glue but it did not happen to work properly. Somehow I had no signal for days until one day the UV sensor decided to throw funny values. IT was time to change it and redesign it.

So I did a bit a research like some of you did and decided to cover my UV sensor for a better protection (of course )
Borosilicate and silicon based materials tend to offer the best transmission range (source); typically UV-C to near-IR.
This encompasses the full spectre of UV light. But given the UV-C are mostly absorbed by the atmosphere layers, we are left with mainly UV-B and UV-A at the surface of the globe.

JGS1 being a source of interest in this thread and is equivalent to Suprasil 1 and 2 (Heraeus), Spectrosil A and B (Saint-Gobain) and Coming 7940 (Coming), Dynasil 1100 and 4100 (Dynast).
I decided to hunt for the Spectrosil® that is a synthetic fused silica. It has excellent optical transmission from 180 nm in the deep UV through to 2000 nm in the IR.

(a bit of history) Heraeus Quarzglass acquired back in 2008 the Saint-Gobain Semiconductor Materials and Optical Products lines, which includes the Spectrosil products.
There are several manufacturers on the market for such products, and eventually I selected this one.

The transmission for a 3mm thickness is given by:



Around 93% transmission in UV-B and UV-A range. This rather good as the EPA defines the UV index (or strength of UV radiation) is calculated for several wavelengths between 280 and 400 nm:

Wavelength Strength Weight Result
290nm | 4 | 15 | 60
320nm | 26 | 5 | 130
400nm | 30 | 3 | 90

I opted for the coated version, of a 25mm, 3mm thick piece which I mounted on my enclosure.



Mounted on my enclosure: the UV sensor is maintained just underneath.





It's sealed with Epoxy.

It should behave properly now

Thanks,
Zitoune

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(Another) UV sensor for WeatherDuino Pro2 weather station, the VEML6075 - Superpat - 15-02-2017

Hi,

I can find no reference to this sensor in the WeatherDuino forum:- Veml6075

This is an I2C  device that does both UVA and UVB    N.B.  NOT the Veml6070 which is UVA only!

This device contains its own amp and A-D and temperature compensation.

Attached is a app note,   designingveml6075.pdf  This note has some interesting graphs and info on covers.

These devices can be purchased on a breakout for about £10 from China. (Ebay)

There are two Ardunio libraries on git hub.

Any use to us?

regards

Patrick

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RE: UV sensor for WeatherDuino Pro2 weather station - uncle_bob - 15-02-2017

Certainly good info in the datasheet.

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RE: (Another) UV sensor for WeatherDuino Pro2 weather station, the VEML6075 - werk_ag - 15-02-2017

(15-02-2017, 11:01)Superpat Wrote:  Hi,

I can find no reference to this sensor in the WeatherDuino forum:- Veml6075

This is an I2C  device that does both UVA and UVB    N.B.  NOT the Veml6070 which is UVA only!

This device contains its own amp and A-D and temperature compensation.

Attached is a app note,   designingveml6075.pdf  This note has some interesting graphs and info on covers.

These devices can be purchased on a breakout for about £10 from China. (Ebay)

There are two Ardunio libraries on git hub.

Any use to us?

regards

Patrick

Hi,

Interesting info... thank you.
Do you have a link for the Arduino libraries?

Most of the breakout boards I found on eBay are 3V devices, however it seems that there are 5V versions too.
http://www.ebay.com/itm/DIP10-Size-VEML6075-UV-AB-Light-Sensor-Module-for-Arduino-/322279081951?hash=item4b095487df:g:JHQAAOSwTA9X7zUW

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RE: UV sensor for WeatherDuino Pro2 weather station - Superpat - 15-02-2017

https://github.com/schizobovine/VEML6075

https://github.com/kriswiner/VEML6075

AFAIK the device will runfrom 3 to 5

Cheers

P

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RE: UV sensor for WeatherDuino Pro2 weather station - Superpat - 16-02-2017

Hi,

Another very simple library from:-

https://s3.amazonaws.com/linksprite/LinkerKit/vishay+sensors/libraries.zip

linksprite make a linker breakout with the sensor.

cheers

P

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RE: UV sensor for WeatherDuino Pro2 weather station - AllyCat - 16-02-2017

Hi,

Yes that's a very interesting Aplication Note. It's the first description I've seen to obtain the "real" UVIndex from a Low-cost* sensor, without the very expensive (erythema action spectrum) UV filter used by Davis.   * So low-cost that RS won't send less than 5, but perhaps you need that many as it's a SMD package:  Dimensions: 2.0 x 1.25 x 1.0 mm. 
 
In particular, I noted the following detail from page 12 and the calibration method: "The  correct  UV  index  needs  a  well-calibrated  measurement  tool, such as the Davis weather station used to calibrate  the VEML6075."  

   

 Cheers,  Alan.

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RE: UV sensor for WeatherDuino Pro2 weather station - werk_ag - 17-02-2017

I can't say when, but at some point I will gonna make some tests with this sensor. It looks very interesting.
Integrating it in the WeatherDuino Pro2 system will not be a problem, and it can become an anternative to the UVM-30A

The good weather is comming...

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RE: UV sensor for WeatherDuino Pro2 weather station - tyntop - 17-03-2017

Hi,

I have been following this discusion for some time, as I intend to add this module to my setup.

With regards to a cover for the UVM-30-UV, I came across this shop on ebay selling watch spares, I've looked in their shop and found that they sell face lens in both acrylic and crystal glass in varying diameters, thicknesses, domed or flat.

Prices seem fairly reasonable

Might be worth a look

http://stores.ebay.co.uk/clock-watchparts?_trksid=p2047675.l2563

Hope this is of use.

regards

tyntop

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