Tiny UV Alarm


So as commented my son (4) has a rare condition so he can't be exposed to UV light (the Sun, halogen and some other artificial lights). There are other issues but UV exposition is a high risk.

At the moment the sensitive device to measures the ambient UV light:

  • has a display for values up to 1999
  • measures from 1 uW/cm2
  • powered by 9V DC battery,
  • it's slightly bigger than box of cigarettes 
  • cost more than $250 imported from US.


Here an example on how big the current metter is (it is not the real one)

My goal is to create a simple but portable alarm of UV light,

  • detects from 1 uW/cm2
  • that makes sound when there is any UV light,
  • powered by rechargable 3.7 VDC coin battery,
  • has the charger inside and charges via USB
  • as small as a badge button,
  • cost 10 times less (around $25).

Current prototype V.3 Tiny UV alarm

At the moment I accomplished the UV functionality and power requeriments already with three prototypes, one in protoboard and arduino mega, later with arduino nano, and now with the arduino Cheapduino, very small but capable enough. On the way I tried with a ATtiny85, and others, but the Cheapduino gives me enough versatility for easy programming, handles the digital sensor and makes the alarm.



Tiny UV alarm system unfolded to see the details with programming setup attached


Now I'm on the way to srink it more, proves that works OK with battery requeriments, and finally design a proper PCB with all components. I think some more people from many countries can benefit from this device.

It's going to be a long project so any idea or suggestion is welcome. Thanks!


Great Idea

Fantastic Francisco, I see you want to fit it into a badge I am not sure what you mean by a badge. Do you mean like a badge that has a pin on the back side that you attach to you shirt or something. It looks like it would be small enough to fit into a oversized watch case. This might give you an idea.

I want to hear more about this very good idea. 

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"Necessity is the mother of invention"

Nicely done!

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looks beautiful

looks beautiful

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Thank you sw0rdm4n. I have to say I’m more proud about the functionality than the look, but thanks! :wink:

It’s right!


Thanks Cole! Yes, we need it so we invented it :wink:

Thanks for the tip


You are right even my efforts on miniaturization, maybe it’s better to use another format because it can damage the fabric. Thanks for the tip! :wink:

Interesting project

Which sensor do you use?

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I use the an I2C UV sensor, why?

Thanks for response. I have

Thanks for response. I have no special reason for my question. In my opinion sensors (or method of measurement and data processing) are most important for this kind of projects. So I was curious. Good luck with your project!

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