Wristify your body temperature!

Imagine you’re in the bus leading you home. Outside it’s snowing, the bus is stuck in traffic, you’re damn freezing. Well, soon you’ll just have to touch something on your wrist in order to feel warmer almost instantaneously. This magic something is called Wristify and is one of the thousands awesome technological inventions made day by day at MIT. Press and official images can be found on the official webpage of the project. In this post we’ll see its basic working principle.

wristify

Technically, Wristify is a thermoelectric bracelet based on the principle that heating or cooling the skin on one part of the body can make the entire body feel warmer or colder. Developed by four MIT engineering students who adopted the motto “thermal comfort, reimagined“, this interesting device is supposed to help cutting the amount of energy currently used to heat or cool entire buildings. Logically, if everyone could be able to autonomously tune their body temperature according to their preferences, there wouldn’t be need to continuously heat, for example, huge rooms for conferences or shopping malls areas. Ideally, in the long term, it would be reasonable to expect significant savings.

Currently at working prototype stage (15 models have been developed up to now), this portable mini-heater looks like a wristwatch. The key difference is the custom copper-alloy-based heat sink on which Wristify’s working principle depends. Readings from embedded thermometers measure external and body temperature. With such information, an automated control system automatically adjusts the intensity and duration of thermal pulses that are delivered to the wrist via the heat sink. Thanks to a lithium polymer battery, the current prototype can run for up to 8 hours. As previously said, the team found that minute, rapid changes in temperature on one part of the human body can affect the whole body. They discovered that a change of 0.1° C per second is the minimum rate required to make the entire body feel several degrees warmer or colder (the current prototype is capable of a rate of change of up to 0.4° C per second).

The team recently took out the first prize in MIT’s annual Making And Designing Materials Engineering Competition MADMEC (USD 10,000). They plan to use the money to continue development of the device, aiming to develop more advanced algorithms and improve the automation of the thermal pulses.

wristify-1

sources: this, that and another one 

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inFORM – touch THROUGH the screen!

No introduction is needed. First of all, watch this video:

Ok, now we can take a deep breath and try to understand how a group of awesome people from MIT Tangible Media Group got such an awesome achievement. As we can read on their website, their goal is to “couple the dual world of bits and atoms by giving physical form to digital information”. To this aim, they run a host of projects (all of them are amazing!), one of which is the inFORM. I simply copy-paste here some content of the webpage describing this device 🙂 Obviously, all rights belong to the authors and more detailed information can be found on their official website.

sphere_hands02inFORM is a Dynamic Shape Display that can render 3D content physically, so users can interact with digital information in a tangible way. inFORM can also interact with the physical world around it, for example moving objects on the table’s surface. Remote participants in a video conference can be displayed physically, allowing for a strong sense of presence and the ability to interact physically at a distance.

scheme inFORMPast research on shape displays has primarily focused on rendering content and user interface elements through shape output, with less emphasis on dynamically changing UIs. We propose utilizing shape displays in three different ways to mediate interaction: to facilitate by providing dynamic physical affordances through shape change, to restrict by guiding users with dynamic physical constraints, and to manipulate by actuating physical objects. We explore potential interaction techniques and introduce Dynamic Physical Affordances and Constraints with our inFORM system, built on top of a state-of-the-art shape display, which provides for variable stiffness rendering and real-time user input through direct touch and tangible interaction. A set of example applications demonstrates how dynamic affordances, constraints and object actuation can create novel interaction possibilities.

There is also a paper about that! 🙂

touch

muscle contraction and EMG analysis

By chance I found this interesting article on the web. I decided to collect some useful information about muscle contraction and EMG analysis. Voilà 🙂

As God Wikipedia reports, “Electromyography (EMG) is a technique for evaluating and recording the electrical activity produced by skeletal muscles”. Skeletal muscles are, as their name suggests, attached to the bones of the skeleton by means of tendons. Such muscles are controlled by the nervous system (precisely, the somatic nervous system, which is part of the peripheral nervous system). Thus, they can be activated voluntarily.

skeletal muscleThis image clearly shows that muscle fibers are the basic cellular units of skeletal muscles. They are long, cylindrical and multinucleated cells also called myofibers or myocytes.

If we zoom in on a single muscle fiber, we find that it contains myofibrils, whose diameter is about 1-2 micrometers! Myofibrils are very long chains of sarcomeres, that are the contractile units of the cell.

sarcomere

The sarcomeres are composed of protein filaments, some of them are thin (actin) and some others are thick (myosin). During the muscle contraction process (video explanation here), the thick filaments pull the thin ones towards the center of the sarcomeres, thus shortening (contracting) the length of the myofibrils, of the myofibers and, as a consequence, of the muscle itself.

Muscle contraction can be seen as the production of mechanical energy caused by either a chemical imbalance or an electrical impulse (motor neurons). The electrical activity related to this process can be measured by means of EMG analysis.

emg

An electromyograph is needed to detect the electrical potential (up to 30 mV) generated by muscle cells at the moment of their electrical or neurological activation. Electrodes (or needles) are positioned on the patient’s skin (or inserted inside the muscle) and the electrical activity is recorded. The result is a signal called electromyogram, that can be analyzed for diagnostics (detection of medical abnormalities and measure of useful parameters) or to analyze the biomechanics of the considered movement. Muscle tissue at rest is normally electrically inactive. When the muscle is voluntarily contracted, action potentials begin to appear. As the strength of the muscle contraction is increased, more and more muscle fibers produce action potentials. When the muscle is fully contracted, there should appear a disorderly group of action potentials of varying rates and amplitudes (a complete recruitment and interference pattern).