[Yoshinok] recently posted an Instructable on doing a $10 smartphone-to-microscope conversion. The hack isn’t so much a conversion as just a handy jig, but it’s still interesting. The basic idea is to set up a platform for the slides, and to mount the smartphone directly above. The trick, and the reason this can be called a microscope, is that [Yoshinok] embeds the lens from a cheap laser pointer into the smartphone holder. He is able to get 40x optical magnification with the lens, and even though it sacrifices quality, he uses the built-in digital zoom to get up to 175x magnification.
By itself, you could use this with a light source to magnify 3D objects. [Yoshinok] demonstrates this with a dime. But since the slide holder is made of clear acrylic, he mounted a cheap LED flashlight in the base to serve as through-sample lighting. Using this setup, he was able to observe the process of plasmolysis.
If you have kids, this is certainly a project to do with them, but we can’t help but think it will be useful for non-parents alike. This sort of magnification is good enough for simple lab experiments, and given that most Hack-a-Day readers have these parts lying around, we figure the cost is closer to $0. If you give it a try, let us know your results in the comments!