General description The Workout Orb (formerly: Weather Orb Muscle Cool Trainer) is a device that allows you to keep track of the progress in your workout (such as lifting weights) as well as to improve its quality. The Workout Orb Ideation process The concept for The Workout Orb is based on two of our original ideas, first a wearable gesture interface and second a weather simulator orb. Having originally decided on the weather simulator we then used brainstorming techniques to further elaborate on this idea. Ideation process – from ideas to final concept During this process we decided that having an output device would not be satisfactory. To create a direct interaction we were looking for an interesting input device. The decision to use the orb as a tool to improve ones workout was made by being inspired by another group that tried to utilize a workout stepper as in input device. Since this device was not available for our group, we thought about an alternative way measuring workout / muscle activity. Through further brainstorming and lots of trial and error the exact details for our project formed very much on the go and in response to problems that we found. Functionality Inside the wristband three contacts that are part of an Electromyography (EMG) sensor that connect to ones skin to measure muscle activity. A gyroscope, to measure xyz movement of the arm, is also implemented. These sensors in combination give access to information on when your arm moves in which direction and most importantly with what kind of intensity and effort. The built wristband is comparable with the MYO (https://www.thalmic.com/myo/) input device, which will be hopefully released in the near future. 😉 The wristband – our input device Analyzing this data, meaning the timing, duration and direction of ones lifting weights is assessed and then visualized via coloured LEDs inside the Orb. After successfully finishing the workout session a set of lifts a short jingle and a light pattern are played to indicate the completion. To optimize performance The Workout Orb also evaluates the positioning of the lifting arm and thus can detect whether the exercise is performed in a way that is beneficial or warns with an acoustic signal when you start making movements that may have a negative effect on your training of even health. Components and inner workings Hardware Input The wristband as actually a recycled headband that is shortened to half size. As already stated, the input interface consist of two different kinds of sensors, an EMG sensor and a Gyroscope (not shown on the picture below). Compared to the upcoming MYO our wristband was not wireless and required a special power-supply with a positive and a negative voltage. Thus of a lack of money we utilized two ordinary 12V supplies to also create a negative potential. Components of the armband. There are two actual sensors, which are attached on a particular muscle that has to be measured and a third sensor (the reference sensor), attached to a bony part of the arm to calculate the relative change. Output The Orb is build from a plastic sphere mounted onto the base of a former lava lamp (the remains of which are used as weight for testing). Inside a laser-cut piece of acrylic holds the LEDs and the vaporizer. The insides of the orb Since both of the components, LEDs and vaporizer, require more than the 5V the Arduino offers, they are connected to transistors on the breadboard to use an external power supply. Those transistors are then controlled by the Arduino which, for reasons of water-proofness is located outside (and preferably far away from the orb). The Arduino connections furthermore contains resistors with the intend of preventing voltage leakage from the transistor that might give the LEDs unwanted colours (which happened a lot during early testing). Next to the breadboard there is also a piezo element inside the base to provide audio-feedback slightly amplified by the metal casing as a resonating body. Circuit layout of the output device. Software Input The event that triggers a successfully performed movement is detected by a deflection of the delta value in muscle activity. Additionally the delta values of a gyroscope are used to detect if the movement is also performed in the right direction. The sensor processing is taking place on the Arduino micro controller itself. Furthermore the sensor raw data and the sensors delta values are transmitted via USB to the computer, where our own software visualizes these in graphs. This software also allows the user to set their own arm and hand gestures to a free chose able function. The setup is simple: The user can assign a key to a desired gesture, that he is able to record. After saving it, the computer tries to find the recorded pattern in the current sensor data. Representation of the sensor data, later to be processed and visualized in the orb. Output To assess the progress of the workout the Arduino internally differentiates 256 states of training process which in turn also provide (with a little math) the the LEDs brightness to form red light at the beginning gradually turning yellow and then green upon completion. To control how many exercises have to be made to complete one workout set, the speed, i.e. the value added per exercise, can be varied. The so generated colour is then flashed every time the motion is detected, gradually fading away in a simple loop. Upon reaching state 255 (or more) the piezo element is triggered using the already existing code for playing sounds´which we modified to play something that seemed slightly more appropriate than Happy Birthday or Super Mario music. Encountered problems Two occurences can be counted as the major challenges faced troughout the construction of The Workout Orb. The first being the matter of sensor data classification. This describes the process of taking the raw sensor data, identifying the desired patterns and consistently responding to them. The second challenge was that of regulating the power supply for all components. Since all elements (except for the piezo acutator and the Arduino itself) required at least 12 V, some 24 V, extensive use of transistors had to be made. However these proved to be unreliable and often didn’t cut power entirely when they were supposed to. Varying designs using resistors were tested that ultimately provided satisfactory but not optimal results. Another minor challenge in this field was the fact that some transistors died on us due to the heat while soldering.It consists of a wristband worn near the elbow that measures the rotation and muscle activity of ones arm. It then sends this data to the Arduino and thus triggers the feedback in the second component, the actual orb. This component cosists of a translucent orb that is filled with water, which, when turned on, is nebulized to form mist. It is then illuminated by LEDs to give visual feedback. The orb also harbors a small piezo element that additionally allows feedback in the form of sounds an melodies.
We however mastered all these challenges and were able to present a working prototype that not only proved to be a good learning experience but might also be a glimpse into the future and the possible uses for the MYO released end of this year and other gesture interfaces.