DIY_Smartphone_Microscope_H

See this project and more in Make: Vol. 44. Don't have the issue? Get yours today!

Build this project and more in Make: Vol. 44. Don’t have the issue? Get yours today!

You can easily turn your smartphone camera into a powerful digital microscope. All you need is a few tools, the focus lens from a cheap laser pointer or two, and about $10 worth of materials from the hardware store.

Not only will this homemade microscopy stand take high-quality macro photos, but with the ability to magnify objects up to 175x (or 325x if you use two lenses), you can easily see and photograph cells. You can even do laboratory experiments — we were able to observe plasmolysis in red onion epidermal cells.

You’re not restricted to a laboratory setting with this microscope. It was designed to be easy to operate, lightweight, and portable. Just align your phone’s camera with the focus lens on top of the camera stage, then place the object you’d like to view on the adjustable specimen stage.

Since I first shared this project on Instructables, I’ve added a second lens for higher magnification, springs to keep the specimen stage steady, and plexiglass slides to make switching samples clean and easy.

Because the stages are also constructed with plexiglass, objects can easily be viewed with or without an external light source. This lets you use the microscope in a wide range of settings — in the classroom, outside, or in your own home — to take a closer look at the world around you.

Here’s how to make it.

Steps

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Step #1: Extract the laser lens (optional)

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  • The focus lens of just about any laser pointer will serve as the macro lens on the microscope stand. Don’t waste money on an expensive model; the lens from a $2 laser is fine. To achieve higher magnification (up to 325x), use two! You can also buy the bare lenses online (see the Parts list above) and skip this step.
  • To get the lens from the laser pointer, start by unscrewing the front cone and the back cover of the tube. Remove the batteries. Using the eraser end of a pencil, push the innards out of the front of the tube.
  • The front of this assembly is where the focus lens sits. Unscrew the small black plastic retainer in front of the lens and the lens will come free.

Step #2: Find the lens orientation

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  • The lens is not symmetrical when viewed from the edge. You’ll see a thin, translucent strip (~1mm) on one side of the otherwise transparent lens (in this photo it’s shown on the left side). This side must face away from the camera. You can determine the correct orientation by sticking the lens between the prongs of a hairpin, then taping the rig to the back of your smartphone as shown in the second photo here. The correct orientation will provide you with a larger field of view.
  • As it is, you can take reasonably good macro photos with just this lens and your smartphone. But it’s extremely hard to keep the phone steady when taking zoomed-in photos. That’s why you need to build a stand!

Step #3: Cut and drill the stand

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  • Mark the top of the plywood base at the front 2 corners, 3/4" in from both the sides and the front edge. Make a third mark centered 3/4" from the back edge.
  • Stack the plexiglass camera stage (7"×7") on top of the base. Then stack the specimen stage (3"×7") on top of the camera stage, with 3/4" of the specimen stage extending over the front of the base. Clamp and drill through the entire assembly.
  • The bolts that stick up through the base must be counterbored in order for the stand to sit flat. Flip the base over and counterbore the holes with a spade bit to accommodate the bolt heads.
  • TIP: Put a sacrificial piece of wood beneath the plywood base before drilling. You don’t want to damage your workbench.
  • Skill Builder: Drill acrylic without cracking: Acrylic is prone to cracking when cut or drilled. Here’s how to prevent it: First, put a piece of tape over the area you’re about to drill. For drilling thick acrylic, skip the tape and spray WD-40 as a cutting fluid to add lubrication. Measure and mark, then drill slowly, using a sharp bit and gentle pressure. Do not press hard — let the drill do the work.

Step #4: Mount the laser lens

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  • Find a drill bit slightly smaller than the diameter of the lens. Then measure, mark, and drill a hole in the camera stage, 3/4" from the front edge, in line with the bolt holes.
  • Press-fit the lens into the hole. If it doesn’t quite fit, use a file or sandpaper to enlarge the hole. Work slowly and test the fit often. It’s easy to overshoot and make the hole too large! You can remedy this with tiny bit of glue, but be very careful not to get glue on the lens surfaces.
  • When using the stand, it’s important to have the lens as close as possible to the camera. If you plan to keep your phone in a case when you use the stand, then leave the top of the lens slightly exposed so that it will rest closer to the camera. Otherwise, mount the lens flush with the stage.

Step #5: Mount a second lens (optional)

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  • If you’re using 2 laser lenses, mount them one above the other in the camera stage, inserting one lens from below and the other from above. This increased my magnification to ~325x.
  • Be careful not to let these lenses touch, and install them as level as possible. Failure to do so can cause aberrations in the image.

Step #6: Place the light source

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Next, drill a shallow hole in the base to accommodate your light source. (Small LED click lights work well.) It’s important that your light source is directly below the focus lens. To mark the right placement, first test-fit the base, bolts, and camera stage together, then slide the camera stage down to the base and mark the base with a pencil, directly beneath the lens.

Step #7: Assemble the microscope

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  • Start with washers and nuts to hold the 3 bolts tight to the base. Add some upside-down wing nuts and then washers to the 2 front bolts. Then place the specimen stage on top of these washers.
  • Add a nut to each bolt, and lower them about 1/2". Then put a compression spring over each front nut and bolt, and rest the camera stage on top of the nuts.
  • A level is handy here to make sure that the stage is actually flat. If you don’t own a level there are plenty of free level apps for a phone! Use wire cutters or pliers to trim or adjust the springs if necessary. When the stage is level both front to back and left to right, tighten down the final nuts.
  • The compression springs keep the specimen stage stabilized and allow you to make far finer adjustments with the wing nuts. Without these springs, the specimen stage can tilt one way or another if the load is imbalanced or if the bolt holes are too large.

Step #8: Make some slides

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  • The focal length of the lens is very short and the specimen stage can only be raised so close to it because of the nuts holding up the camera stage. Using a transparent sample slide fixes this problem and makes manipulating samples while viewing easier. Simply cut a 2"×4" piece of plexiglass.
  • With 2 lenses, the focal length gets even smaller, so 2 plexi slides are required.

Step #9: Take amazing pictures!

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  • Or video! With $10 worth of materials and a smartphone, you just made a digital microscope.
  • Align your smartphone camera lens with the microscope lens. Bring the object into focus by slowly turning the wing nuts on either side, then use your phone to take a picture or video, or even zoom in for a closer look.
  • I’m a major proponent of making home science more accessible. My goal in designing and building this phone-to-microscope conversion stand is to provide an alternative to overly expensive microscopes. This setup is a viable option for underfunded science classrooms that would not otherwise be able to perform experiments requiring a microscope. But more than that, this device will allow people to rediscover the world around them.
Kenji Yoshino

Kenji Yoshino

Kenji Yoshino studied chemistry at Grinnell College and currently works for Grin City Collective, an art residency in central Iowa.


  • irregularshed

    I’m sure I’m not the only reader concerned by how you managed to get a photo of a cat’s tongue…

    • Scott Tuttle

      just what I scrolled down here to ask. cat got your tongue?

    • Jamie

      Maybe it was Schrodinger’s cat

    • Would it also be a concern if it was a cow’s, a pig’s, or a chicken’s tongue?

      • irregularshed

        Given those animals are routinely slaughtered for meat (and their tongues available from butchers in two cases), not so much.

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  • Donald Merand

    Thanks for posting such a cool idea! I’ve been slowly putting together the parts for this, and finally got it built! I just wanted to share a few of the photos.

    I’m not sure if it’s in keeping with the super-DIY aspect or not, but I was designing my version in OnShape, and decided that it might work well with a 3d-printed base. I’ve made the CAD model I made public in case anybody else wants to use that: https://cad.onshape.com/documents/d5ad86c04e534eab8a3b279a/w/c764ba0001314495a275fff5/e/40c14f409a21407b99b2542e . I used metric M6x1 hex-head screws, nuts, and wingnuts in my design.

    I’m including a couple of photos that I took of it, including one of my PCB ruler to show the level of magnification that I got from my particular lens.

  • Kalpesh Kulkarni

    Though the images are not that sharp. It’s pretty amazing!