I have recieved my order from Sparkfun. Among the stuff i ordered was a luminosity sensor,  the TLS2561. Sparkfun made a great tutorial for it. Rather than soldering pins to plug it to a breadboard, i soldered female jumper wires. Since this sensor has to be exposed to light, a little lenght of wire will make it much more simple.

This sensor works on I2C, and is easy to use, thanks to the provided library.

Depending on the conditions, you can set a gain, and exposition time, so that it can be used in low light condition as well as in bright light.

I have tested it indoor, but i lack another lux sensor to compare the accuracy. However, it will do for now to obtain an idea of the sun level. I have been able to measure 1 lux up to aproximately 60 000 lux.

I plan on screwing the breakout board on a little support, and add some transparant material in front so that i can measure outdoor luminosity without fear of rain or moisture.