BrickScope - Lego compatible working microscope and optics learning kit

The BrickScope - a simple but powerful platform for microscopic discovery.

BrickScope is a system of 3D printed parts that can be used to make a real, working microscope at minimal cost and no specialised skills. The BrickScope parts are a complete redesign based on what we learned from our previous designs, and includes all the parts required to build a functional microscope using some Lego and some simple, inexpensive additional components. This is a great way to start exploring the microscopic world around you, and also makes a good platform for experimenting with light, optics, and microscope design. 

Most importantly, the microscope can be built and configured in a huge range of variations - upright, inverted, horizontal, whatever you want or need. The parts here are all that is needed for a simple but functional microscope, but they can also be used at the core of something more complex and sophisticated - the possibilities are limited only by your imagination and creativity.

All the example images shown here were made using the simplest version of the BrickScope and a basic commercially available set of prepared slides.

Apart from the 3D printed parts and some Lego, what else do I need?

There are only two extra pieces needed - a lens (microscope objective) and a sensor. Specifically, you need a finite conjugate lens with RMS threads. However, most microscope lenses available commercially from Amazon and similar retailers fit this description and will work fine. Any magnification will work, but lower magnification lenses (e.g. 4x) will be easier to get started with.

Note: if the lens has a “∞” symbol on the lens, this won't work - this is an infinite conjugate lens that requires an extra tube lens to form an image. However, these are mostly found in expensive, research grade microscopes. In this photo of two Olympus 10x lenses, the one on the left is has “∞/-” at the bottom of the text, indicating an infinite conjugate lens - this won't work easily with the BrickScope. The lens on the right has “160/-” at the bottom. This is a finite conjugate lens and will work fine. Other lenses may have a number other than 160 - this is fine; anything other than the ∞ symbol will work

For the sensor, you either need to use a camera sensor, or your own eye. However, for your own eye to work effectively, you need an ocular lens (AKA an eyepiece). Like objective lenses, eyepieces can be bought from places like Amazon etc. 

The two eyepiece parts are sized to accommodate the most common eyepiece sizes. The holes are slightly oversized - if you want a tight fit, the easiest solution is just to wrap the barrel of the eyepiece in tape.

For cameras, a simple option is to use a Logitech C270. To use with the appropriate BrickScope module, clip off the front panel, remove the three screws (but don't throw the away!) on the faceplate and remove it. Unscrew and remove the lens then attach the camera to the printed BrickScope module using the 3 faceplate screws.

An alternative camera option is to use a c-mount camera. 

There are two variations of the c-mount adaptor - the wide variant has more clearance around the threaded parts, at the cost of fewer stud attachments. Many cameras sold for microscopy (and astronomy) use c-mount threads, but good, cheap and easily available alternative is the Raspberry Pi HQ camera.

Sample Stage

The sample stage comes in 3 variants. The first is has a lego compatible underside and is most suited to an inverted (i.e. sample above and lens below) type configuration. This works best for fixed focal distance setups where the distance between the lens and the sample is fixed. In these cases, the approximate focus is achieved with a set number of Lego bricks/plates, and fine focus is achieved by twisting the lens in and out of the threads. The thread length of most lenses is longer than the thickness of a Lego plate, so this should allow any length focal distance to be set.

The second version is identical, apart from being smooth on both sides. Either can be used for adjustable focus set ups, but the second version is a simpler print. 

In both cases the sample (e.g. a microscope slide) can just be placed on top of the sample holder. A simple mechanism to adjust focus is to place focusing wedges underneath the ends. Pushing the wedges in and out adjusts the height of the sample as long as bricks are placed in the corner cutouts. The stabilizing bricks can be placed on a printed baseplate part, or on any of other main BrickScope modules (or any other Lego structure). 

The third version is for a horizontal microscope configuration. Here the stage is attached to two 2X2 plates. A simple way to make this configuration work The easiest way to hold a sample like a microscope slide in place when using this is with rubber bands. 

You can set this up any way you want, but attaching this to some lego wheels makes for a simple and effective focusing mechanism. 

In addition to the main BrickScope modules there are a couple of extra accessories to play with:

Filter Holder

The filter holder is designed to fit the space of a 4 stud full brick. When inserted into the side closest to the lens the opening will cover the light path.

For fluorescence microscopy, coloured filters glued (or taped) to the filter holder will allow fluorescence emission to be detected.

Cheap photographic lighting gels work well as fluorescence filters - this is the approach used in the EnderScope, which is a good starting point if you want to give it a try.

Other filters can be added here and swapped easily whenever you want.

Reflector block

The reflector block is build to be attached to 4x4 Lego studs, and one surface of this piece is angled at 45 degrees. There are several uses for this piece. Covering this with reflective tape allows illumination to be easily directed through the sample - useful if you are using something like a torch for illumination which can be tricky to put underneath. 

Attaching a proper mirror to this can also be used to make more creative set ups - using two like this would let you make a light path with the lens and camera both on the same side of the microscope.

Experiments to try

Change the number of bricks between the lens and the sensor/eyepiece. Note what happens to the focussing distance and the magnification. When the lens is further from the sensor the magnification is increased and the focusing point moves closer to the lens.

Place a linear polarizer on the filter holder, and another on the light source, rotate the polarizers relative to each other, and observe what happens to the sample in between.