For centuries, people have been using patterns to communicate information in an eye-catching way. QR codes are no different, although they require a barcode scanner to decode rather than a knowledge of Navajo Native American history.
November is National Native American Heritage Month, and as part of their celebration, [ngaskins] and their students are making seed bead bracelets with QR codes. When scanned, each QR triggers a story written by the student in the form of an audio file, a video clip, or an animation. [ngaskins] says that this project was inspired by eyeDazzler, a beadwork tapestry made with software that generates Navajo weaving patterns.
The students started by designing their bracelets on graph paper, software, or a virtual loom before getting the seed beads and the tweezers out, and decided whether they would use a static or dynamic QR code. Aside from the aesthetics of beadwork, the bead loom is good for teaching math and computational ideas because the beads are laid out in rows and columns. It’s also a good tool for teaching lines of symmetry.
QR codes can hold quite a bit of information. In fact, there’s enough room in a version 40 QR for an executable version of Snake.
If you know anyone who does crafts, they probably have a drawer with a few million beads loose and mixed together. You’ll sort them out one day, right? Probably not. Unless, of course, you build a robot to do the dirty work for you. That’s what [Kalfalfa] did, using some Phidgets boards, a camera and Open CV. You can see a video of the cardboard machine doing its thing below.
Maybe it is because we are more electronics-minded, but we were impressed with the mechanism to grab just one bead at a time from the hopper. If you watch the video, you’ll see what we mean. However, sometimes a bead jams and a magnetic sensor figures that out so the controller can reverse a bit and try again.
Continue reading “Robot Sorts Beads By Color”
When you consider that almost every single cell in your body has more than a meter of DNA coiled up inside its nucleus, it seems like it should be pretty easy to get some to study. But with all the other cellular gunk in a crude preparation, DNA can be quite hard to isolate. That’s where this cheap and easy magnetic DNA separation method comes in. If it can be optimized and tested with some help from the citizen science community.
Commercial DNA separation methods generally involve mixing silica beads into crude cell fractions; the DNA preferentially binds to the silica, making it possible to mechanically separate it from the rest of the cellular junk. But rather than using a centrifuge to isolate the DNA, [Justin] from The Thought Emporium figured that magnets might do a better job. It’s not a new idea — biotech companies offer magnetic separation beads commercially, but at too steep a price for [Justin]’s budget. His hack comes from making magnetite particles from common iron compounds like PCB etchant and moss killer, and household ammonia cleaner. The magnetite particles are then coated with sodium silicate solution, also known as waterglass. The silica coating should allow the beads to bind to DNA, with the magnetic core taking care of separation.
[Justin] was in the process of testing his method when he lost access to the needed instruments, so he’s appealing to the larger science community for help optimizing his technique. Based on his track record of success in fields ranging from satellite tracking to graphene production, we’ll bet he’ll nail this one too.
Continue reading “Cheap And Easy Magnetic DNA Separation Method Needs Your Help”