Square Root of Not

In previous articles I’ve demonstrated how to use littleBits and erector set parts to build a magnetic stirrer and a sample rotator. Since I was able to drive Erector set machines with the littleBits motor I decided to try to use it to drive K’nex contraptions.

To some, it might seem that you can patent anything these days. Last week a weird story appeared in my Facebook newsfeed: Amazon has somehow been able to patent photography against a white background. The story was originally reported on DIY Photography. It has been making the Internet rounds since. The Electronic Freedom Foundation points out that the story made it onto the Colbert Report. But things aren’t always as they appear.

If you could save the lives of 2.7 million children would you do it? I think it is safe to say that most people would answer “yes.” You may be thinking, "But I am only one person—how could I make a difference?" You have family, don’t you? You have friends, don’t you? You have colleagues and coworkers, don’t you? You could save the lives of 2.7 million children by doing nothing more than informing your family, friends, colleagues, and coworkers about Vitamin A Deficiency (VAD) and the simple, safe, inexpensive, and sustainable solution: Golden Rice.

In a previous article I wanted to know if I could use the recording medium from old floppy disk as an infrared (IR) filter to shoot infrared photography on an iPod. I built a simple IR detector using Snap Circuits to test how well the floppy disk would absorb visible light yet let infrared wavelengths pass through. In that circuit I used the photodiode Snap Circuits block (Infrared Receiver U24) as the infrared detector. Even though a photodiode was useful for building a simple IR detector, another electronic component that is often used to detect infrared light is the phototransistor.

Occasionally I’ll come across a web page that shows you how to make an infrared (IR) filter for your iPhone (in my case the iPod Touch) out of an old floppy disk. I had an old floppy disk so I decided to see if it would actually work. The process is actually fairly simple: take apart a floppy disk, cut out enough of the disk (the Mylar and iron oxide recording medium) to cover camera lens, tape the piece of floppy disk over the lens, point your camera, and shoot your picture.

I actually did have an old floppy disk that I could use for this experiment:

In honor of the upcoming National Robotics Week (April 5-13, 2014), I’ve created “CockroachBot” based on my Snap Circuits programmable robot I designed for last year’s robotics week. CockroachBot will try to run away when it detects a particular level of light falling on its light dependent resistor. I designed CockroachBot to be easy to build completely out of Snap Circuits parts and easy to program to inspire folks from seven to centenarian to get interested in robotics.

There’s a popular YouTube video featuring mathematician Edward Frenkel where he describes how the NSA hacked our emails. It is a backdoor into the National Institute of Standards and Technology public key encryption standards.

I’ll borrow an analogy for a simplified description of how public key encryption works from Simon Singh. Imagine a sturdy metal box that can be locked shut with a padlock.

This build is a simplified Leeuwenhoek microscope made from CD-ROM drive parts and construction toys. My initial design was simply a rectangle of corrugated cardboard with a hole punched in it and one of the glass spheres from the Chem C3000 kit, but the magnification was disappointing and the field of view surprisingly narrow. Another method would have been to demonstrate melting a glass rod, drawing it to a thin glass fiber and then heating the fiber into a glass sphere. Though this would have been historically appropriate, it might be difficult to find this type of glass rod and they might be expensive.

I was able to find the EYESPY Spydercam at Goodwill. Several hacks for it came to mind, but the simplest is attaching it to a remote control vehicle. I have an old Lego remote control car that’s been gathering dust so I decided to use it for this article. You can, however, attach it to any remote controlled vehicle you may have. I've attached it to the Popular Mechanics RC Tank--hint: use a rubber band to fasten the Spydercam to the battery block. You might not be able to find the RC Tank any more except on eBay. I've also attached it to the Snap Circuits Rover.

In a previous article I built a magnetic stirrer using littleBits and Erector set parts for the home laboratory. At the end of the article I added a design for a sample rotator (a device used to continuously mix lab samples). I have (somewhat) improved the design of the Erector set and littleBits sample rotator and in this article I document the build.

The Rotator ”Base”

Follow me on Twitter: @SteveSchuler20. Back in the day, some chemistry sets came with a mechanical centrifuge. They were operated similar to those old-timey pump style tin spinning toy tops. This is the style centrifuge that came with my chemistry set:

Note: I came up with this story idea long before I was able to find a second-hand salad spinner and now I can’t remember where I found this picture. I am unable to cite its source.

Here’s another example of a chemistry set centrifuge on Evil Mad Scientist Laboratories’ site:

In the comments section of my previous article I demonstrated an optical Theremin. This article is the build for that circuit. The circuit and circuits that are similar to it in function have also been called a “Light Sensitive Tone Generator,” “Photo Theremin,” and “Audible Light Meter.” These three circuits are usually based on the two-transistor Light Sensitive Tone Generator from The Forrest Mims Circuit Scrapbook, Volume 1 (Radio Shack, 1976). The circuit built in this article is based instead on the 555 timer IC.