Create an open source UV-C photometer from Arduino-compatible components

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Joined Dec 19, 2018
I did the green banana test on my diy UV-C Sterilizer (see and the results were decidedly underwhelming. Since I got no response from the UV-C bulb manufacturer to my inquiry for UV-C irradiance information, I am understandably nervous as to whether there is sufficient germicidal effect from my sterilizer. I, therefore, need a way to measure UV-C irradiance around the 254nm wavelength, and I imagine there are other makers who might also need to measure the irradiance of their own UV-C projects.

I did a little research and I found the 1918 ANALOG UV SENSOR BREAKOUT Board (see and that looked promising except that it has very poor sensitivity in the germicidal UVC wavelength range.

But then I saw that the GUVC-S10GD photodiode has a spectral range of 220nm - 280nm, which is ideal!

Do you think the GUVA-S12SD photodiode on the 1918 ANALOG UV SENSOR BREAKOUT Board could be de-soldered and replaced with the GUVC-S10GD photodiode (or the GUVC-S40GD, or something similar) to get a better UVC sensor breakout board for germicidal UVC projects?

I don’t have enough electronics experience yet to understand what sorts of modifications to breakout boards are possible, so I’m reaching out to other engineers & makers who have more expertise. It would be great to open source a diy project for building a UV-C photometer around an Arduino and some inexpensive off-the-shelf components.