Planet Arduino

Input devices consisting of optical readers for punched paper tape have been around since the earliest days of computing, so why stop now? [Jürgen]’s Paper Tape Reader project connects to any modern computer over USB, acting like a serial communications device. Thanks to the device’s automatic calibration, it works with a variety of paper materials. As for reading speed, it’s pretty much only limited to how fast one can pull tape through without damaging it.

While [Jürgen]’s device uses LEDs and phototransistors to detect the presence or absence of punched holes, it doesn’t rely on hardware calibration. Instead, the device takes analog readings of each phototransistor, and uses software-adjusted thresholds to differentiate ones from zeros. This allows it to easily deal with a wide variety of tape types and colors, even working with translucent materials. Reading 500 characters per second isn’t a problem if the device has had a chance to calibrate.

Interested in making your own? The build section of the project has all the design files; it uses only through-hole components, and since the device is constructed from a stack of 1.6 mm thick PCBs, there’s no separate enclosure needed.

Paper tape and readers have a certain charm to them. Cyphercon 4.0 badges featured tape readers, and we’ve even seen the unusual approach of encoding an I²C byte stream directly onto tape.

“Measure twice, cut once” is great advice in every aspect of fabrication, but perhaps nowhere is it more important than when building a CNC machine. When precision is the name of the game, you need measuring tools that will give you repeatable results and preferably won’t cost a fortune. That’s the idea behind this Arduino-based measuring jig for fabricating parts for a CNC build.

When it comes to building on the cheap, nobody holds a candle to [HomoFaciens]. We’ve seen his garbage can CNC build and encoders from e-waste and tin cans, all of which gave surprisingly good results despite incorporating such compliant materials as particle board and scraps of plumber’s strapping. Looking to build a more robust machine, he finds himself in need of parts of consistent and accurate lengths, so he built this jig. A sled of particle board and a fence of angle aluminum position the square tube stock, and a roller with a paper encoder wheel bears on the tube under spring pressure. By counting pulses from the optical sensors, he’s able to precisely position the tube in the jig for cutting and drilling operations. See it in action in the video after the break.

If you’ve been following [HomoFaciens], you’ll no doubt see where he’s been going — build a low-end tool, use that to build a better one, and so on. We’re excited to see him moving into more robust materials, but we’ll miss the cardboard and paperclip builds.

Leonardo Lupori and Raffaele Mazziotti are active in the field of neuroscience at Tommaso Pizzorusso’s lab at Neuroscience Institute CNR of Pisa respectively as molecular biologist and experimental psychologist. They created an Arduino-based and MATLAB-controlled tool called IOSIC (Intrinsic Optical Signal Imaging Chamber), powered by an Arduino Micro and focused on intrinsic optical signal (IOS) imaging apparatus to run experiments on the plasticity of the brain.

Intrinsic optical signal (IOS) imaging is a functional imaging technique that has revolutionized our understanding of cortical functional organization and plasticity since it was first implemented, around 30 years ago. IOS is produced by the brain when processing information and is similar to the information recorded with the plethysmograph (the instrument to measure heart rate from a finger) and it is useful to investigate how the brain works. The researchers are especially interested to investigate how the brain is able to adapt to the environment to store information but also acquire new skills and these studies are really useful to understand what happens to the brain when is in good health or during a disease.

Even if their lab has a long-standing expertise in electrophysiological studies, they decided to  developed a fully functional apparatus for IOS with tools already available and low-cost:

To set up the entire system we used a mix of components commercially available and custom-made. The most expensive tool we used is an imaging camera from Hamamatsu (it is necessary because we need to analyze data quantitatively), but you can also use a cheaper camera (at least with a CCD chip 12-bit depth is recommended). The rest is stuff collected from old tools of the lab. For example, the microscope, that in our case is an old Olympus confocal microscope, but any transmitted light microscope or macroscope should be ok, was already in the lab and is currently used also for other purposes. For light illumination, we used a custom made crown-shaped LED holder that can be attached to the objective and provide a really stable light source. Afterwards, we wrote a MATLAB script to control the camera and then we built an imaging chamber to analyze the animal preparation. The imaging chamber is essential to keep the animal stable during the imaging session (about 7 minutes) and also to maintain its physiological temperature during the time course of anesthesia. An additional feature added to the chamber is the possibility to change the animal’s visual field automatically allowing us to measure rapidly, efficiently and repeatedly a very important parameter of plasticity called ocular dominance. The chamber is composed by a 3D printed structure on which an Arduino MICRO, two servo motors, a heating pad, an IR thermometer and a magnetic ring have been installed. Currently we are using this system with success and we hope to discover something really relevant.

You can download IOSIC code for the Arduino MICRO here. The code uses third-party libraries : TMP006 and Servo. MATLAB code to control shutters is available here.