Monday, November 25, 2013

Building a Microscope

Recently, I stumbled across some directions for making my own microscope with a small collection of hardware-store parts and a smartphone. It looked like fun, so I thought I'd give it a try!

Overall, I'd say this project turned out pretty well. The directions on Instructables were very straight-forward. The only part I had to wing a bit was drilling the hole for the lens; I ended up using a 1/4" bit and "wiggling" a bit to enlarge the hole. Even still, the lens was a very tight fit, and it didn't fit quite flat. But it seems to have fit flat enough to give me good images.

One issue I encountered with the final construct was that I couldn't get the stage as close to the lens as it wanted to be to make focusing easy. I removed some washers, but still had issue. The easiest solution turned out to be simply stacking two blank slides underneath my subject matter.

Of course, once I got the thing assembled, it was time to try it out! :) I found a pretty inexpensive set of sample slides from Elenco and gave them a look!

My favorite thing about this rig is that the smartphone camera is so straightforward to operate; electronic zoom, auto focus. And of course, capturing images with the built-in camera couldn't be more straightforward!

Microfilm reference slides

Bird feather
Nylon fiber
Grasshopper wing
Grasshopper leg
Fish scale
I tried adding an LED touch-light as under-lighting for the stage, but it blew out the camera; this might work if I used some semi-translucent material to block the intensity.

Wednesday, November 20, 2013

Experience building the RadioShack 3D LED Cube Kit

While looking for something to use a gift card on, I stumbled across the Radio Shack 3D LED Cube Kit for Arduino. It'd been awhile since I'd tried building an electronics board project from scratch, and I'd seen some clever demos of "3D pixel" displays; I thought I'd try my hand at putting this together. What follows is my experience with it.

Sunday, November 3, 2013

Personal experience: Patching a Galaxy Nexus with (expired) sugru

After several lucky years, I finally dropped my Galaxy Nexus in just the right way to crack a corner of the screen. I did a bit of research and found that one of the things sugru can be used for is to shore up a crack like that. I gave it a try, and I'm pretty happy with the results. The full steps are here; this is my personal experience following this process.

Note: If you follow this hack, be aware that it is not suitable for repairing cracks that intrude into the display or touch-sensitive areas of the screen. The hack guide on points that out also, but I wanted to make it clear here to save you the trip if you've got a bigger crack.

So, some thoughts:

  1. Sugru is great stuff to work with. It's easy to mould, cleans quickly off of hands, and cures to a very nice, smooth-but-grippy surface. Documentation on it warns of possible allergic reactions to uncured sugru; I had no problems.
  2. The package of sugru I used was a free gift from a project last year; it was actually significantly past the expiration date (2012-12-13). I found that it still worked, but subsequent comments should factor that in.
  3. I found the steps of the guide suggesting you "delicately place the sugru into cracks" and "gently guide your finger" to be pretty untenable; the sugru I was working with had the texture of Play-Doh and tended to rub off of the phone or break up with too much handling. As a result, I ended up with a bit of a bulge in the finished product; I find it passable, but my wife doesn't score it to highly for attractiveness and it fires both of our OCD circuits. :) There is a good FAQ on how to get a smooth finish; I didn't try this process myself. I had thought that perhaps kneading it would make it less gummy, but I didn't try that; the same FAQ suggests this would not be desirable.
  4. My biggest concern trying this was that I'd inadvertently cover the front-facing camera. Fortunately, keeping the sugru off of the camera was quite easy, and I've noticed no diminished picture quality.
Sugru's pretty handy stuff. Now that I've gotten a chance to try it, I'm going to add it to my toolbox on future projects.