I have to work out how to get a moving mirror to reflect sunlight onto a static target mirror. Rather than calculate where the sun will be at a particular moment in time and then adjusting the mirrors position to suit, I have decided to set up a feedback loop. The target mirror will talk to the tracking mirror. If the reflected light goes off course the target mirror will tell the tracking mirror and it will make the necessary adjustments. I’m testing some tiny FM transceivers for the job.
This is the cheapest and easiest way I know to create two-way communication with the Arduino (my preferred micro controller). My preferred FM modules is the RFM12B used by Jean-Claude Wippler in the fantastic JeeLabs modules. I got my RFM12Bs from Modern Device.