DIY Microscope

The invention of the microscope completely changed people’s view of their surroundings.  They suddenly became aware of an invisible parallel world – with tiny creatures that caused some of our previously mysterious diseases, and a level of complexity beyond imagination.  The DIY microscope described in this article will only give you a glimpse into that world, but it’s surprisingly easy to make and a fun project none-the-less.

The Most Basic “Microscope”

The basic idea is simple enough.  You take the lens out of a common laser pointer, and place it in front of a phone’s camera (a hair-clip and tape are perfect for holding it in place).  I’m not 100% sure where I first saw the idea, but it was probably this imgur tutorial.  They don’t even call it a microscope – it’s just a ‘macro lens’.

Laser pointer lens held over the phone's camera with a hair-clip and tape.

Laser pointer lens held over the phone’s camera with a hair-clip and tape.

I completely destroyed the laser pointer while trying to get the lens out, so that’s something you should be aware of.  It was fairly cheap, but the cats have lost a favourite toy.  So what sort of results can you expect?  As a rough guess I would say that you will get around 30x – 40x magnification, and a couple of example images are included below.

Close-up view of coin

Photograph of coin taken free-hand (full resolution inset).

The image below is a classic beginner’s choice for a microscope.  If you’ve ever chopped onions you’ll know that between the thick layers you’ll often see a very thin, film-like layer.  This layer is only one cell thick, and so it’s perfect for looking at cell structure.  To get the image below I spread the skin over a plastic drinks bottle, and then shone a light in at an angle.

view of onion skin cells

Onion skin spread over a plastic bottle, with a light shining in (full resolution inset).


Improving the Microscope

The concept was taken a step further by Yoshinok in his instructable.  It can be quite tricky to get a stable photograph when you’re holding the phone in your hand, so Yoshinok’s proposal is a stand to hold things steady, and the use of wing nuts for fine adjustments to the focus.  I strongly recommend reading that guide, and also watching this matching video; but the design didn’t quite work for me.  My variation is shown below.

view of microscope stand

An alternative design for the microscope stand.  Ignore the hair-clip and lens, it’s just there for storage and must be stuck onto the phone before use.

Firstly, the precision needed when drilling the hole for the lens seemed too tight for me.  Instead I simply cut out an opening on one edge; which meant that I could still use the lens held in place by the hair-clip.  Secondly, sourcing and cutting the acrylic seemed like too much work, so I just used the cover off an old DVD case.  Thirdly (and the only change not driven by laziness), the focal length of the lens that I was using was very short, which meant that the item being viewed had to be very close to the lens.  Yoshinok’s design wouldn’t have allowed me to focus, so instead I used an extra set of bolts that suspended the DVD case from above.

Front-view of the stand. You can see how the viewing platform (DVD case) is raised and lowered by the four bolts.

Front-view of the stand. You can see how the viewing platform (DVD case) is raised and lowered by the four bolts.


The ability to hold the camera in-place, and make fine focusing adjustments, makes a huge difference.  Not just in the end results (some examples of which area shown below), but also because you can get a good picture first time.  When you’re holding it in your hand you might need to take two or three before you get a good one.

Close-up of coin

Photograph of coin taken using the stand (full resolution inset).


Time for the onion skin again.  This time the light is coming from directly underneath.  I used a head-torch pointing upwards, and covered it with a sheet of paper to diffuse the light.

Photograph of onion skin taken using stand (full resolution inset).

Photograph of onion skin taken using the stand (full resolution inset).



Because a major part of this microscope is a mobile phone, if you upgrade your phone then you have (in theory) upgraded your microscope.  The images above were taken on a phone that has an 8 megapixel camera.  The image below was taken on a newer phone that has a 13 megapixel camera (60% more pixels!).

The familiar coin; but now taken with an 18 megapixel camera.

The familiar coin; but as seen through a 13 megapixel camera (full resolution inset).

The first thing that you will probably notice is the white halo around the edge of the image.  I think that the higher resolution camera has a wider lens.  Because the camera lens is wider than the magnifying lens, what you are seeing is the edge of the magnifying lens itself.  The main image also seems less magnified than for the lower resolution camera.  However, the inset shows that full magnification is still pretty much the same.  The higher resolution camera is essentially just using the extra pixels to record a larger area of the coin.


More Things to Look At

Coins and onion skins are certainly very exciting; but there is of course a huge variety of things that you could look at.  In the summer months you will most likely find the occasional deceased insect to examine – the inside window ledge is a good place to look.

Unidentified beatle found on window ledge.

Unidentified beatle found on window ledge.

One thing that you’ll notice is that your microscope has a very shallow depth of field.  That is to say, for a subject like a beetle, you will only be able to focus on part of it at a time.  In the image above I tried to focus on the head.  Anything closer (e.g. back leg) and anything further away is blurry.  This is why coins and onion skins are good choices – because they are mostly flat – and also why on microscope slides specimens are often sandwiched between two glass plates.

However, you can still get some great views of specific parts of insects – such as the eye of a bee shown below (the bee unfortunately met it’s end in a pool of water in my garden).  You can also remove parts of the insect to try and get them to lay flat, and produce better images – like the wing of the bee shown further below.

Close-up of a bee's eye.  The unfortunate bee drowned in a pool of water in the garden.

Close-up of a bee’s eye.

Bee wing

Bee wing.

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