Tuesday, November 16, 2010

Light Intensity Measurement

I did a little useless experiment. Added two photo-resistors to a micro-controller. One pointed outside to the lower sky and one inside my room, facing a wall. Micro controller is connected to my netbook. Netbook records measurements every few seconds and filters, plots and uploads a graph of the light intensity of both sensors every 5 minutes. It is fully automated and completely useless. Click to enlarge.

6 comments:

  1. Fun. I sea a distinct peak on both days at the inside resistor. Was that in direct sunlight or a reflection of it?

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  2. I am not sure. It cannot be direct light. I will have to check it around 13:30.

    The small light it still receives afters sunset is when I have my lights on in my room. There the outside sensor senses some reflection in the window. You can see that I went to the AH just after 18:00 yesterday and then went to football training for about 3 hours. You can also see when I went to bed although I fell asleep with some lights on the first day.

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  3. Oh an yesterday was a perfectly clear day. The spikes in the curve is when a tree gets in the way of the sun.

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  4. It's auto updating, nice! Gloomy day today.

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  5. nice!

    fun to see the difference in outdoor & indoor light levels.

    Also, where were you on 16/11 between 19:30 and 22 hr?

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  6. Chasing a ball in the fog.

    I just made a picture of the setup, you can see that in the plot, I turned a light on it for my phone :)

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