This is an interesting project for gathering pollen samples for analysis. It’s basically a fan controlled by a PIC16F690. The fan draws air over a piece of sticky tape for a specific amount of time in hopes of catching some airborne particles. Apparently it works quiet well. Be sure to check out the all the pictures of the pollen, spores, and “weird stuff” that was collected.
The idea is simple: a timer-controlled fan would produce constant airflow over a sticky tape and hopefully will make some of the airborne particles stick; attach the tape on a slide, pop it under the microscope and you are in business.
More about this DIY air sampler