is there a way to distinguish between daylight and artificial light in a room? I'm thinking my options are a light intensity sensor or a color temperature sensor. The sunlight is supposed to be much stronger than artificial light. But I'm wondering if the case will be the same inside a room. Or does the idea seem silly to distinguish between both?
Electronic – Sensor to distinguish between daylight and artificial light in a room
light-sensorphysicssensor
Related Solutions
For such a sensor network I would absolutely consider using Dallas 1-wire components for great flexibility and reasonable price. It is well supported in Linux via owfs.
At www.hobby-boards.com there is a small T3-R1-A ready made board which you just connect with cat5/RJ45 priced at 18USD. According to the documentation it uses the DS18S20 sensor like already mentioned by BG100.
Since LEDs used as photodiodes are most sensitive to the colour they emit during normal operation, a basic colour sensor can be made using the LED in reverse and an opamp:
The circuit above came from this page. It can also be done the other way round - a much more detailed look at colour sensing using LEDs and light sensors is available here - this page details using a normal light sensor and different colour LEDs.
I couldn't find the app note mentioned in the comments, but this page seems to be quite a thorough treatment of the subject of transimpedance amplifiers. You can alter the bias across the LED to change response time/sensitivity.
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Best Answer
Methods off the top of my head:
Look for UV, the sun has a lot of UV. Indoor lights do not. That's the simplest difference between the sunlight and artificial light.
Monitor the brightness. It's hard to tell because your eyes rapidly adjust, but a sunny day outside is 5-50 times brighter than "bright" indoor lights. The downside to this is that an overcast day, and bright indoor lighting will begin to overlap. https://www.engineeringtoolbox.com/light-level-rooms-d_708.htmlhttps://www.engineeringtoolbox.com/light-level-rooms-d_708.html