I'm working on a little project that needs to know the heading to the brightest light source-- usually the sun. It's a mobile system that will need to update itself every ~1 to 5 seconds.
I was thinking of using a few light sensors-- at least four?-- but would rather not sacrifice four analog pins.
Using the LED light sensing hack could work, but that would then need eight digital pins four four light sensors.
I've found photocells and light sensors (like Photocells), and they're easy enough to interface with, but I'm curious if folks have any tips on light sensor configurations or could suggest any other ways to solve this problem.
Thanks!
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Maybe you could get by with half the number of analog inputs if you wired two sensors on opposite sides of the craft in series, and tapped off the center point into the A/D. So if the illumination was equal on each side the A/D voltage would be V/2, and V or 0 for the extremes on one side or the other. Just a thought.
Makes sense-- thanks!
Searching around after posting, I decided to order a few 4501's to get over this hurdle for reals...
http://www.arduino.cc/playground/Learning/4051
Basically you want to build an infra-red seeker head. This can be done with just one sensor, just like they did back in the 60's when IR detectors were huge and needed active cooling to any kind of sensitivity.
This article explains the basics Heat-Seeking Missile Guidance, but I'm thinking this may be a little too complex, but it is one option if you really don't want to use up pins 