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.


cybrbeast said...

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

annom said...

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.

annom said...

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

cybrbeast said...

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

pimp-a-lot bear said...


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

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

annom said...

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 :)