UV sensor...

[Pimpom]

I\'d like to be able to determine the intensity of UV radiation
from different sources like CCFLs, the sun under various
conditions, UV torchlight, etc. The sensor doesn\'t have to be
very linear, only approximately so. It\'s not necessary to measure
the absolute intensity either - knowing the relative values is
enough.

Will a UV LED work? I don\'t have any with me, so I can\'t just try
it out.

 

[Martin Brown]

On 03/08/2020 08:36, Pimpom wrote:

I\'d like to be able to determine the intensity of UV radiation from
different sources like CCFLs, the sun under various conditions, UV
torchlight, etc. The sensor doesn\'t have to be very linear, only
approximately so. It\'s not necessary to measure the absolute intensity
either - knowing the relative values is enough.

Will a UV LED work? I don\'t have any with me, so I can\'t just try it out.

Probably but you might need a piece of Wood\'s glass from a black light
in front of it so that only the UV can get to the sensor.

https://en.wikipedia.org/wiki/Wood%27s_glass#History

Otherwise blue and violet light will also generate photoelectrons.

--
Regards,
Martin Brown

 

[Pimpom]

On 8/3/2020 1:22 PM, Martin Brown wrote:

On 03/08/2020 08:36, Pimpom wrote:
I\'d like to be able to determine the intensity of UV radiation from
different sources like CCFLs, the sun under various conditions, UV
torchlight, etc. The sensor doesn\'t have to be very linear, only
approximately so. It\'s not necessary to measure the absolute intensity
either - knowing the relative values is enough.

Will a UV LED work? I don\'t have any with me, so I can\'t just try it out.

Probably but you might need a piece of Wood\'s glass from a black light
in front of it so that only the UV can get to the sensor.

https://en.wikipedia.org/wiki/Wood%27s_glass#History

Otherwise blue and violet light will also generate photoelectrons.

Ah yes, there\'s that. Even if I manage to get Wood\'s glass -
which I doubt - I wonder how the IR component of sunlight will
affect a UV diode.

 

[Tabby]

On Monday, 3 August 2020 10:45:52 UTC+1, Pimpom wrote:

On 8/3/2020 1:22 PM, Martin Brown wrote:
On 03/08/2020 08:36, Pimpom wrote:

I\'d like to be able to determine the intensity of UV radiation from
different sources like CCFLs, the sun under various conditions, UV
torchlight, etc. The sensor doesn\'t have to be very linear, only
approximately so. It\'s not necessary to measure the absolute intensity
either - knowing the relative values is enough.

Will a UV LED work? I don\'t have any with me, so I can\'t just try it out.

Probably but you might need a piece of Wood\'s glass from a black light
in front of it so that only the UV can get to the sensor.

https://en.wikipedia.org/wiki/Wood%27s_glass#History

Otherwise blue and violet light will also generate photoelectrons.

Ah yes, there\'s that. Even if I manage to get Wood\'s glass -
which I doubt - I wonder how the IR component of sunlight will
affect a UV diode.

use a bit of exposed photographic film.

IIRC the incoming radiation needs to be higher frequency than the LED is designed to ouput, so you\'d use blue to sense UV but not RGB. I\'m not certain on that point though.

ISTR someone using a combination of 2 permanent marker pens to make a uv filter. Might find it on youtube.

....All these bits of info need checking.


NT

 

[Clive Arthur]

On 03/08/2020 08:52, Martin Brown wrote:

On 03/08/2020 08:36, Pimpom wrote:
I\'d like to be able to determine the intensity of UV radiation from
different sources like CCFLs, the sun under various conditions, UV
torchlight, etc. The sensor doesn\'t have to be very linear, only
approximately so. It\'s not necessary to measure the absolute intensity
either - knowing the relative values is enough.

Will a UV LED work? I don\'t have any with me, so I can\'t just try it out.

Probably but you might need a piece of Wood\'s glass from a black light
in front of it so that only the UV can get to the sensor.

https://en.wikipedia.org/wiki/Wood%27s_glass#History

Otherwise blue and violet light will also generate photoelectrons.

Could using a phosphor and a visible light detector work?

--
Cheers
Clive

 

[Jan Panteltje]

On a sunny day (Mon, 3 Aug 2020 15:15:43 +0530) it happened Pimpom
<nobody@nowhere.com> wrote in <d1RVG.233570$iXb1.152409@fx03.ams1>:

On 8/3/2020 1:22 PM, Martin Brown wrote:
On 03/08/2020 08:36, Pimpom wrote:
I\'d like to be able to determine the intensity of UV radiation from
different sources like CCFLs, the sun under various conditions, UV
torchlight, etc. The sensor doesn\'t have to be very linear, only
approximately so. It\'s not necessary to measure the absolute intensity
either - knowing the relative values is enough.

Will a UV LED work? I don\'t have any with me, so I can\'t just try it out.

Probably but you might need a piece of Wood\'s glass from a black light
in front of it so that only the UV can get to the sensor.

https://en.wikipedia.org/wiki/Wood%27s_glass#History

Otherwise blue and violet light will also generate photoelectrons.

Ah yes, there\'s that. Even if I manage to get Wood\'s glass -
which I doubt - I wonder how the IR component of sunlight will
affect a UV diode.

There are several substances that light up bright blue in visible
light when exposed to UV:
https://www.thoughtco.com/what-glows-under-a-black-light-607615
I tried that once with an EPROM eraser light and quinine,
for banknotes etc I now have an UV flashlight.
That way you can use a normal photo diode.
Then you still need an UV pass filter:
https://www.instructables.com/id/Photography-in-the-Ultraviolet-spectrum/
there is your Wood\'s glass.

 

[Chris Jones]

On 03/08/2020 17:36, Pimpom wrote:

I\'d like to be able to determine the intensity of UV radiation from
different sources like CCFLs, the sun under various conditions, UV
torchlight, etc. The sensor doesn\'t have to be very linear, only
approximately so. It\'s not necessary to measure the absolute intensity
either - knowing the relative values is enough.

You might (and probably should) be interested in what sort (wavelength)
of UV you are measuring as well. For example, a wavelength of 350nm is
UV, and is good for curing some glues or exposing the photoresist on a
PCB, but it is fairly useless for killing germs which requires more like
250nm wavelength. So, without giving more information about the purpose
of your measurement, it is possible that the suggestions you receive
will be correct but not really useful and perhaps more misleading than
no measurement at all, of for example it leads you to believe that
something has been sterilised and in fact it has not.

 

[George Herold]

On Monday, August 3, 2020 at 3:36:39 AM UTC-4, Pimpom wrote:

I\'d like to be able to determine the intensity of UV radiation
from different sources like CCFLs, the sun under various
conditions, UV torchlight, etc. The sensor doesn\'t have to be
very linear, only approximately so. It\'s not necessary to measure
the absolute intensity either - knowing the relative values is
enough.

Will a UV LED work? I don\'t have any with me, so I can\'t just try
it out.

Hi pimpon, IDK. You somehow have to select what wavelength \'band\'
you want to see. This could be with some UV filters, or spectrometer
and a broad band detector (photodiode) or pick a detector with some
wavelength response that you can use.

I think of Forest Mimms for led\'s as detecotrs...
http://www.forrestmims.org/scientificresearch.html
here\'s an article about measuring the ozone layer.
http://www.forrestmims.org/images/SCIENCE_PROBE_TOPS_PROJECT_NOV_1992_small.pdf

George H.

 

[amdx]

On 8/3/2020 2:36 AM, Pimpom wrote:

I\'d like to be able to determine the intensity of UV radiation from
different sources like CCFLs, the sun under various conditions, UV
torchlight, etc. The sensor doesn\'t have to be very linear, only
approximately so. It\'s not necessary to measure the absolute intensity
either - knowing the relative values is enough.

Will a UV LED work? I don\'t have any with me, so I can\'t just try it out.

 Hi pimpom,

 I did a little research and when I was about to post I see it is you,
I forget where you are located, but realize it is difficult for you to
get many things we have accessible in the US.

That said, any chance to get one of these?

Amazon link,


General Tools UV513AB Digital UVA/UVB Meter, 280-400 nm

$137.

> https://tinyurl.com/yxfld4rx

                                Mikek


--
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

 

[Pimpom]

On 8/3/2020 7:09 PM, George Herold wrote:

On Monday, August 3, 2020 at 3:36:39 AM UTC-4, Pimpom wrote:
I\'d like to be able to determine the intensity of UV radiation
from different sources like CCFLs, the sun under various
conditions, UV torchlight, etc. The sensor doesn\'t have to be
very linear, only approximately so. It\'s not necessary to measure
the absolute intensity either - knowing the relative values is
enough.

Will a UV LED work? I don\'t have any with me, so I can\'t just try
it out.
Hi pimpon, IDK. You somehow have to select what wavelength \'band\'
you want to see. This could be with some UV filters, or spectrometer
and a broad band detector (photodiode) or pick a detector with some
wavelength response that you can use.

I think of Forest Mimms for led\'s as detecotrs...
http://www.forrestmims.org/scientificresearch.html
here\'s an article about measuring the ozone layer.
http://www.forrestmims.org/images/SCIENCE_PROBE_TOPS_PROJECT_NOV_1992_small.pdf

George H.

You and others have brought up the question of which UV band I\'m
interested in. I have no specific application in mind at the
moment. I just wanted to have a general idea of how UV levels
differ between sources and, in the case of the sun, with the
weather and its position in the sky.

If I had to choose filter and sensor types for wavelength, I\'d
start with near UV in the mid-300s nm.

My problem, as usual, is that there\'s little chance of getting
the filter materials mentioned by people on the internet,
especially with the pandemic disrupting everything. To make
things worse, with the tension between India and China, I don\'t
know if I\'ll still be able to order from AliExpress.

 

[Martin Brown]

On 03/08/2020 17:35, Pimpom wrote:

On 8/3/2020 7:09 PM, George Herold wrote:
On Monday, August 3, 2020 at 3:36:39 AM UTC-4, Pimpom wrote:
I\'d like to be able to determine the intensity of UV radiation
from different sources like CCFLs, the sun under various
conditions, UV torchlight, etc. The sensor doesn\'t have to be
very linear, only approximately so. It\'s not necessary to measure
the absolute intensity either - knowing the relative values is
enough.

Will a UV LED work? I don\'t have any with me, so I can\'t just try
it out.
Hi pimpon, IDK.  You somehow have to select what wavelength \'band\'
you want to see.  This could be with some UV filters, or spectrometer
and a broad band detector (photodiode) or pick a detector with some
wavelength response that you can use.

I think of Forest Mimms for led\'s as detecotrs...
http://www.forrestmims.org/scientificresearch.html
here\'s an article about measuring the ozone layer.
http://www.forrestmims.org/images/SCIENCE_PROBE_TOPS_PROJECT_NOV_1992_small.pdf


George H.


You and others have brought up the question of which UV band I\'m
interested in. I have no specific application in mind at the moment. I
just wanted to have a general idea of how UV levels differ between
sources and, in the case of the sun, with the weather and its position
in the sky.

Whereabouts are you? There should be a fully calibrated UV photometer at
a local or national observatory. I used to follow the one in Brussels.

Start from here and you can probably find one near you:
https://www.esrl.noaa.gov/gmd/ozwv/dobson/

If I had to choose filter and sensor types for wavelength, I\'d start
with near UV in the mid-300s nm.

My problem, as usual, is that there\'s little chance of getting the
filter materials mentioned by people on the internet, especially with
the pandemic disrupting everything. To make things worse, with the
tension between India and China, I don\'t know if I\'ll still be able to
order from AliExpress.

You just need to find a scrap black light that no longer works and
carefully fracture the outer envelope in a stout bag behind a plexiglass
screen. It isn\'t as dangerous as imploding a TV tube but depending on
the size of the bulb it can be interesting. Mine was a 6\" diameter.

Schott glass or Edmund optics will sell you a real UV filter for a
price. (probably about $50) UG3 or UG11 (much more expensive)

Their much \"Improved\" website is infuriating to use

--
Regards,
Martin Brown

 

[Pimpom]

On 8/3/2020 9:46 PM, amdx wrote:

On 8/3/2020 2:36 AM, Pimpom wrote:
I\'d like to be able to determine the intensity of UV radiation from
different sources like CCFLs, the sun under various conditions, UV
torchlight, etc. The sensor doesn\'t have to be very linear, only
approximately so. It\'s not necessary to measure the absolute intensity
either - knowing the relative values is enough.

Will a UV LED work? I don\'t have any with me, so I can\'t just try it out.

 Hi pimpom,

 I did a little research and when I was about to post I see it is you,
I forget where you are located, but realize it is difficult for you to
get many things we have accessible in the US.

That said, any chance to get one of these?

Amazon link,


General Tools UV513AB Digital UVA/UVB Meter, 280-400 nm

$137.

https://tinyurl.com/yxfld4rx

                                Mikek

Hi, I saw one similar UV meter on Amazon India for about US$100.
Looks good but I don\'t want to spend that much on something I\'m
likely to use a few times and then effectively discard.

For my purpose, I\'d rather rig up something from a few bucks
worth of parts. The filter is going to be the main problem.

 

[Jeroen Belleman]

On 2020-08-03 19:03, Martin Brown wrote:
[...]

Edmund optics [...]

Their much \"Improved\" website is infuriating to use

I see what you mean. Why do they do that? To me it means
\"Get out of here, fast.\"

I erase all cookies systematically every session, anyway.

Jeroen Belleman

 

[Pimpom]

On 8/3/2020 10:33 PM, Martin Brown wrote:

On 03/08/2020 17:35, Pimpom wrote:
On 8/3/2020 7:09 PM, George Herold wrote:
On Monday, August 3, 2020 at 3:36:39 AM UTC-4, Pimpom wrote:
I\'d like to be able to determine the intensity of UV radiation
from different sources like CCFLs, the sun under various
conditions, UV torchlight, etc. The sensor doesn\'t have to be
very linear, only approximately so. It\'s not necessary to measure
the absolute intensity either - knowing the relative values is
enough.

Will a UV LED work? I don\'t have any with me, so I can\'t just try
it out.
Hi pimpon, IDK.  You somehow have to select what wavelength \'band\'
you want to see.  This could be with some UV filters, or spectrometer
and a broad band detector (photodiode) or pick a detector with some
wavelength response that you can use.

I think of Forest Mimms for led\'s as detecotrs...
http://www.forrestmims.org/scientificresearch.html
here\'s an article about measuring the ozone layer.
http://www.forrestmims.org/images/SCIENCE_PROBE_TOPS_PROJECT_NOV_1992_small.pdf


George H.


You and others have brought up the question of which UV band I\'m
interested in. I have no specific application in mind at the moment. I
just wanted to have a general idea of how UV levels differ between
sources and, in the case of the sun, with the weather and its position
in the sky.

Whereabouts are you? There should be a fully calibrated UV photometer at
a local or national observatory. I used to follow the one in Brussels.

Start from here and you can probably find one near you:
https://www.esrl.noaa.gov/gmd/ozwv/dobson/

If I had to choose filter and sensor types for wavelength, I\'d start
with near UV in the mid-300s nm.

My problem, as usual, is that there\'s little chance of getting the
filter materials mentioned by people on the internet, especially with
the pandemic disrupting everything. To make things worse, with the
tension between India and China, I don\'t know if I\'ll still be able to
order from AliExpress.

You just need to find a scrap black light that no longer works and
carefully fracture the outer envelope in a stout bag behind a plexiglass
screen. It isn\'t as dangerous as imploding a TV tube but depending on
the size of the bulb it can be interesting. Mine was a 6\" diameter.

Schott glass or Edmund optics will sell you a real UV filter for a
price. (probably about $50) UG3 or UG11 (much more expensive)

Their much \"Improved\" website is infuriating to use

Thanks for your interest. But I live in one of the most isolated
regions of a third-world country and all those sources are out of
reach for me. Besides, this is something I want to try out once
and then shelve indefinitely, so I want to spend as little as
possible on it.

 

[Clive Arthur]

On 03/08/2020 18:27, Pimpom wrote:

On 8/3/2020 9:46 PM, amdx wrote:
On 8/3/2020 2:36 AM, Pimpom wrote:
I\'d like to be able to determine the intensity of UV radiation from
different sources like CCFLs, the sun under various conditions, UV
torchlight, etc. The sensor doesn\'t have to be very linear, only
approximately so. It\'s not necessary to measure the absolute intensity
either - knowing the relative values is enough.

Will a UV LED work? I don\'t have any with me, so I can\'t just try it
out.

   Hi pimpom,

   I did a little research and when I was about to post I see it is you,
I forget where you are located, but realize it is difficult for you to
get many things we have accessible in the US.

That said, any chance to get one of these?

Amazon link,


   General Tools UV513AB Digital UVA/UVB Meter, 280-400 nm

$137.

https://tinyurl.com/yxfld4rx

                                  Mikek

Hi, I saw one similar UV meter on Amazon India for about US$100. Looks
good but I don\'t want to spend that much on something I\'m likely to use
a few times and then effectively discard.

For my purpose, I\'d rather rig up something from a few bucks worth of
parts. The filter is going to be the main problem.

Would it be possible to use a prism to separate wavelengths? I think
UVA will go through normal glass. I don\'t have a clue, really, but
someone will know.

--
Cheers
Clive

 

[whit3rd]

On Monday, August 3, 2020 at 12:36:39 AM UTC-7, Pimpom wrote:

I\'d like to be able to determine the intensity of UV radiation
from different sources like CCFLs, the sun under various
conditions, UV torchlight, etc. The sensor doesn\'t have to be
very linear, only approximately so. It\'s not necessary to measure
the absolute intensity either - knowing the relative values is
enough.

Will a UV LED work? I don\'t have any with me, so I can\'t just try
it out.

Well, this is still colorimetry; the separation of a bit of spectrum
is the first part, and detection is second.

Either a prism (quartz passes UV) or grating, with some kind of beam-forming (maybe
just a tube with interior painted black) will do light separation, and
a sensor can be either a bolometer or (remember,
vosible light has been filtered) a phosphor that is excited by all the
UV range of interest. The phosphor can be detected with regular-old visible
light ICs intended for photography and such.

Expect, if you select a small part of spectrum, dim light and
noisy data.

A bolometer consisting of a quartz fiber suspending a thermocouple loop, in the focus
of a mirror, will deflect in a magnetic field; this was a classic method of a century ago,
and could detect a cahdle light at a mile distance... electromechanical solutions
and mirrors are not to be despised. That\'s a bit less practical than finding a UV
diode that works in photoelectric sense, but it\'s such an elegant experimental
arrangement!

A light chopper (logic controlled shutter, or a small fan with some phase-detection) would
combine with the right kind of data logging to make a good small-signal amplifier, requiring
only a bit of FFT masssaging to pull small signals out of noise.

 

[server]

On Monday, August 3, 2020 at 3:36:39 AM UTC-4, Pimpom wrote:

I\'d like to be able to determine the intensity of UV radiation
from different sources like CCFLs, the sun under various
conditions, UV torchlight, etc. The sensor doesn\'t have to be
very linear, only approximately so. It\'s not necessary to measure
the absolute intensity either - knowing the relative values is
enough.

Will a UV LED work? I don\'t have any with me, so I can\'t just try
it out.

Look at Sparkfun.com or Adafruit.com for UV sensors, They are also stocked on Digi-key or Mouser. About $6.50 US. for a tiny PCB. Maybe something similar in your country.

 

[Tabby]

On Monday, 3 August 2020 18:27:35 UTC+1, Pimpom wrote:

On 8/3/2020 9:46 PM, amdx wrote:
On 8/3/2020 2:36 AM, Pimpom wrote:
I\'d like to be able to determine the intensity of UV radiation from
different sources like CCFLs, the sun under various conditions, UV
torchlight, etc. The sensor doesn\'t have to be very linear, only

For my purpose, I\'d rather rig up something from a few bucks
worth of parts. The filter is going to be the main problem.

not if you use something that\'s not sensitive to R,G,B,IR.


NT

 

[Jan Panteltje]

On a sunny day (Mon, 3 Aug 2020 13:52:30 -0700 (PDT)) it happened whit3rd
<whit3rd@gmail.com> wrote in
<dd8892b9-0283-4398-8804-dbbaf4e167c0o@googlegroups.com>:

On Monday, August 3, 2020 at 12:36:39 AM UTC-7, Pimpom wrote:
I\'d like to be able to determine the intensity of UV radiation
from different sources like CCFLs, the sun under various
conditions, UV torchlight, etc. The sensor doesn\'t have to be
very linear, only approximately so. It\'s not necessary to measure
the absolute intensity either - knowing the relative values is
enough.

Will a UV LED work? I don\'t have any with me, so I can\'t just try
it out.

Well, this is still colorimetry; the separation of a bit of spectrum
is the first part, and detection is second.

Either a prism (quartz passes UV) or grating,

Indeed, wonder how far into the UV a normal prism of an old pair
of binoculars will go,
by rotating it you can make a nice spectrometer.

 

[server]

On Tuesday, 4 August 2020 06:46:46 UTC+1, Jan Panteltje wrote:

Indeed, wonder how far into the UV a normal prism of an old pair
of binoculars will go,
by rotating it you can make a nice spectrometer.

Would the prism in binoculars be made from dispersive glass?

John