The following instructable describes a 3D printable microscope that you can make at home using low cost 3D printing. Almost every part on this microscope is 3D printable with the exception of the lenses, which you can get from disposable cameras. I got my lenses from a local photography shop and they were very kind to give me a bag full. Since I had so many, I designed it to work with them all. I have also upgraded it with a focus lock and a smartphone adapter so that you can take digital photos of your specimens. The quality of the image is not yet sufficient for scientific work but it is still an excellent educational tool or and can be quite useful around the workshop. You can also find this model and some nice user remixes for high end lenses on thingiverse: http://www.thingiverse.com/thing:77450

Step 1: Get Lenses From Disposible Cameras

You need to locate 4 copies of a disposable camera. The best place to go is a local photography shop or wherever you can get them developed. Ask nicely and people are probably going to be very willing to help.

(CAUTION there is a significant shock hazard if you plan to open a flash camera from the capacitor!)

You will need to print out a different optical tube for the Kodak lenses vs the Fujifilm lenses, STLs for both are attached in the next step. I have tested this design with the following camera models:

Fujifilm QuickSnap Outdoor
Fujifilm QuickSnap Flash
Fujifilm Flash

Kodak FunSaver Flash
Kodak unaned
Kodak Max Outdoor

Use some pliers or otherwise to remove the faceplate on the camera and remove the objective lens. Once again, if you plan to get it from a flash camera, be really careful with the capacitor. Non-flash cameras are trivial. Take good care not to scratch the lenses.

Step 2: 3D Print All the Necessary Components

You will need to print out all the components. This should work with a variety of printers and settings. I printed it on a Makerbot Replicator 2 using black, silver, and white PLA. For the optical tube, rack, knobs, pinion, stage, and head I used 0.1mm, 15% fill and high setting. For the post and stand I used medium settings, 0.27mm, 2.5% fill. It should have enough tolerance for medium settings everywhere. STLs can be found in the attached zip file.

Note: if you plan to use the smartphone adapter or even to prevent loss of focus, you can print the attached focus lock upgrade described later on. If you decide to do that, do not print the head included here in this zip file, use the one from the focus lock.

The light source shown in the photo is a low cost LED wall light from some box store.

Microscope STL files.zip
Download

Step 3: Install Lenses and Assemble Optical Tube

Use the attached photos as a guide for installing the lenses and assembling the optical tube and rack. There is a different optical tube that you have to print for the Fujifilm lenses (11.9mm outer diameter) vs. the Kodak lenses (13.2mm outer diameter). Others may work as well if they have these dimensions and 35 mm focal length. You should not need to put any glue anywhere on the optical tube assembly.

Step 4: Assemble the Head and Stand

Assembly is very straight forward. You may want to add some glue to hold the post, head, stage, and stand together as I found this improves stability. You can also add some glue to hold the focus knobs to the pinion gear inside the head. Be careful to go get glue such that the gear is accidentally bonded to the head.

Step 5: Optional Step - Focus Lock Upgrade

I designed an upgrade to the original model that allows you to lock the focus, this is particularly useful if you use the smartphone adapter. I printed all the parts for this upgrade using the MakerWare high setting, 0.1mm layers and 15% fill on a MakerBot Replicator 2. Once printed, install the nut from the inside of the head and thread the screw. You should then be able to install the remaining parts from the zip file included in previous steps.

Step 6: Optional Step - Smartphone Adapter

If you want to take some digital photos using your phone camera you can also print out this smartphone adapter. I printed all the parts using the MakerWare medium settings and 0.27mm layer thickness. For the two clamps, I printed with a higher infill (30%) for strength and 15% for the body. You will also need a rubber band, I am sure many different kinds will work just fine.

Step 7: Have Fun!

If you like this project, I hope you will vote for it. This was also inspired by some other nice projects:
Wood DIY microscope and great theory section : http://www.funsci.com/fun3_en/ucomp1/ucomp1.htm
Laser cut version by ZombieCat: http://www.thingiverse.com/thing:31632

Looking forward to any feedback as well.