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Uv radiation monitor device using bs2-ic — Parallax Forums

Uv radiation monitor device using bs2-ic

rickrockerrickrocker Posts: 7
edited 2008-03-04 20:51 in BASIC Stamp

Hello everyone...I'm new to this forum and also new to the exciting world of parallax smile.gif. I recently purchased the Board of education(w/BS2-IC) usb with parts kit so that I could work on my·senior year·project...which I·will tell you about later.·So far·things have been going smoothly but I have got stuck on a few aspects of my project and could definitely use some much needed advice.

So here goes the description of the project:

I am working on a UV(ultraviolet) solar radiation monitor that would detect uv radiation energy from the sun and then give a recommended time of exposure to that radiation. Now obviously this would involve a uv sensor or photodiode that would o/p a parameter such as variable(analog)·voltage, current or resistance(very rare).

I have been looking on the web for some photodiodes and uv sensors that would interface with the board of education platform and found one (OKI - ML8511). But unfortunately this one is really tiny and is primarily used in cell phones and ultraportables.

So is there anybody who has worked on a similar project before and can give me a recommendation on a UV photodiode or sensor that I can interface with this platform. And also what other obstacles should I be expecting in the near future idea.gif..


Thank you so much!

http://www.oki.com/en/press/2007/z07004e-2.html

http://www2.okisemi.com/site/productscatalog/MEMS/UVSensors.html

Comments

  • Tracy AllenTracy Allen Posts: 6,666
    edited 2008-03-04 18:03
    Also check out Advanced Photonix. And the giant in the field is Hammamatsu. They offer photodiodes, Gallium Nitride I think, and also the UVtron, which is a UV sensitive phototube that is often used as a flame detector. These devices can be hard to acquire though.

    There may be reason to separate out UVA and UVB for better handle on exposure. The signal is likely to be small, in the range of nanoamps. The full sun earth surface UVA is I recall around 5 W/m^2, and around 1 watt/m2 for UVB.

    On the other hand, you might find a UV emitting LED and use it in reverse as a photodiode, as a quick and dirty. Assume a proportion will be UVA and UVB.

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Tracy Allen
    www.emesystems.com
  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    edited 2008-03-04 18:53
    The TAOS TSL230 light-to-frequency sensor, which Parallax sells, has some sensitivity into the UVA region (320-400nm), but none in the UVB. Ideally, one would be able to cover it with a UV-pass filter for direct measurement of UVA radiation. However, it's an unfortunate fact of life that UV bandpass filters, such as the Schott UG1, also pass far-red and near-infrared, which the TSL230 is very sensitive to. Another thought I had was a subtractive process, wherein you alternately cover and uncover the sensor with a UV-blocking filter and measure the difference in output. But the requirements for doing this may well exceed the sensor's dynamic range. In fact, it is almost certain to saturate in direct sunlight.

    On their website, TAOS lists UV sensing as an app for their light-to-frequency sensors. You might give them a call to see what they had in mind.

    -Phil
  • rickrockerrickrocker Posts: 7
    edited 2008-03-04 20:51
    Thanks guys for the advice..greatly appreciated! I have been looking on the web for other sensors that are primarily concerned with UV Index measurement and I found a couple of German manufacturers with distributors in the US.

    One of them is the ERYCA UV Index Si-C sensor/photodiode whose spectral response nearly matches the erythema curve

    Checkout the datasheet at http://www.sglux.de/fileadmin/datasheets/ERYCA.pdf

    The other one(s) is similar to this and also is used in UV Index measurement...

    http://www.ifw-bauelemente.de/www/ifw_be/english/photodioden/?abteilung=10B8F42D3EF

    This one is more comprehensive and shows a variety of sensors that fall under this criteria.

    Also, one more thing...since my major requirement is a sensor that would easily integrate with the BoE platform...any good UVA photodiode that works with parallax products should also do the job fine . I'm not looking to spend hundreds of $$ on this project..still a student [noparse]:)[/noparse]

    P.S. - Should the ADC0831 recommended by parallax do the job of converting to bits.....I was thinking of using a lookup table stored in the eeprom of BS2 IC to compare values from [noparse][[/noparse] UVA->ADC <-> Lookup Table ] of the UV Index.
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