This is a tiny and cheap microscope that I've created, that anyone can build with almost no money and with just 9 minutes of print.
What you need is two lenses and one spring from two broken DVD players, a needle, two screws and two bolts.
I printed it in yellow but it's preferably a dark color to better frame the images.
You need two (broken) DVD players: you have to remove the laser lens from each of them. Also, extract the little spring.
You also need a short M 2.5 screw and a longer M 2.5 screw (1cm or more), with two bolts.
You can use a needlepin, a needle, or a little metal wire.
Print the microscope.stl file prefably in black or dark color.
Put the lenses with the bold side external, so that the flatter sides of the lenses are in contact with each other. Close the plates with the lenses in the middle. Use the longer screw with bolt for the central hole, the shorter screw with bolt for the upper hole.
Take the spring and position it at 90Â° degrees around the longer screw. It must keep the needle perpendicular to the longer screw and near as possible to the lens.
Now you can put what you wish on the needle. In the photos you see a little piece of a potato peel. This microscope lets you see the single cells.
TIPS: as the magnification is great, you need more light. Watch things in the sunlight or under a lamp. If you watch something thin you can see it through (like the peel of the potato), but if you watch something solid you will need side light.
Bring your tiny telescope with you outside to observe petals, grass, leaves, moss, lichens!