November 17th, 2014

A while ago Pacific Northwest National Laboratory Tweeted about their 1 dollar smartphone microscope. http://availabletechnologies.pnnl.gov/technology.asp?id=393

It involved some small glass beads and a 3D printed clip to hold the bead in front of the camera on a smart phone.  The larger beads can give you 100x magnification, smaller beads provide 350x and even 1000x magnification!  Wouldn’t it be fun to have these in the forest or better yet, at the pond so that we can have students exploring the microflora/fauna as well as the larger invertebrates, snakes, frogs, plants and birds!

We thought we should make some.  I bought beads and had an online 3D printing company make the clips, both of which came in due time (about 2-3 weeks).  I had to fiddle a bit to get these to work, but in the end they did the job they were intended for.  I thought I would share the simple modifications I had to make so that others might get up and going with these a little faster.

The really small beads are .5mm and offer 1000x mag., the middle are 1mm and about 350x mag., and the leftmost are 3.5mm beads for 100x magnification.  I just bought the sample pack of beads recommended by PNNL.  There are enough here for several hundred microscopes.

Here is the clip and a 1mm bead inserted.  This slips over the camera on a smart phone.  I made no modifications to the 3d image files provided by PNNL… this is what you get if you print their exact file.

I wasn’t certain this was going to work, a 1 dollar 1000x microscope sounds a little too good to be true.  So, I wasn’t surprised when the bead wouldn’t fit into the proper hole.  It turns out that each type of 3D printer can have slightly different amounts of shrinkage… which is what I had.  So I got out the digital calipers and measured my drill bits until I found one that was close enough to 3.5mm (I started with the 100x bead).   I carefully drilled a new whole and the bead fit nicely, snug enough that it wouldn’t fall out.

The second problem was that I had printed the generic smartphone clip (I wasn’t sure what device these were going to be used with), and it had lots of extra room at the top so the clip swivelled around on the iPad mini.  Not a big problem, I had the right drill bit so I drilled another hole into the clip at the right place so that the top of the clip was snug with the top of the iPad.  When I slipped the clip onto the iPad it now held the bead in the right place.

But, when I started putting things in front of the bead I got a lot of blurry images.  These glass beads weren’t necessarily designed to be flawless magnifiers.  Plus, I’m sure they get rattled around a bit in shipping so some beads might have scratches on their surface. There are imperfections in most beads so you need to hunt around to find one that is nice and clear.  The other problem is that the beads are small, so cleaning them is a bit tricky.  I just used water and things definitely improved.

Here is a picture of some wood grain (cedar) that I took with the 100x bead.  This image is pretty raw (slightly cropped and level corrected), and should give you a good idea of what to expect from the PNNL 1 dollar smartphone microscope.  In this image it is detailed enough that you can see the scoring caused by the sandpaper… not bad.

Overall, this was an easy build and a little practice got decent images.  I think I will modify the 3d image files to better fit my devices (my iPad mini’s have Lifeproof cases so some modification will be necessary) and have more made.  I will definitely use these with students next spring at our pond.

I will be sharing my modified clips with the other Outdoor Ed. staff and I hope to see some of their photo’s show up here.  I have lots of beads so if a WRDSB school has a 3d printer and want to make their own smartphone microscopes, let me know and I will share some of my beads.

It would be great to