Introducing the Context
While the pulse would be the first layer of our inputs, we also introduced the project in a context that would have to do with its environment. This means that the final behaviour will be the outcome of both the user and its environment. In this direction, we chose the crime maps of London (Metropolitan Police crime maps) as a factor that has the ability to shape the way we feel in the city and constitutes a useful analogy to our pulse rate as well. We recognize that the reputation of a neighborhood for instance, has sometimes the power to change and define our heart rate, especially when we walk by a rather dangerous area. We also know that there will be different conditions that will form the final behaviours, so in this point pneumatics play an important role to the efficiency of what we want to do, as they provide us with a variety of air distributions within the same mechanism.
We suggest a kind of bracelet that has the ability to map (through its behaviour), the pulse of its owner according to where he is in the city and inform him about the criminality of the area he is in and the state of his own body as well. Everyone will be able to wear it and it can be easily identifiable between the users.
Layers of inputs
Each element of data causes waves of responses on the bracelet. The two channels of air represent the level of criminality and the heart beat rate of the user. By changing the angle of the components for the first and the frequency for the second channel, we get to see the representation of the input.
The first layer of data (first circuit) will be the level of criminality of the position of the user in the city, according to its position on in GPS maps of his smartphone. By this we mean that we will take his position from his phone, feed it into processing and then locate the user on the crime map so as to get the level of criminality of his position. Ideally these data would be transferred online from the phone to Processing. This return would cause a response to the bracelet that will inform the user about the level of criminality of the area.
The second layer (second circuit) of data will have to do with the values we get from the pulse sensor. The sensor will be on the user (on the inner side of the bracelet) and will record his/her heart rate. In this case the frequency of the movement represents the average heart rate of the user meaning that for different ranges of heart rates we will get different frequencies.
Behaviours ( Outputs )
On the whole, we define five different levels of criminality: high, above average, average, below average and low (as indicated in the crime maps). For the first level the bracelet will not show any transformation as regards the heart and the criminality rate, so that the user will not draw the attention of his/her environment. For the rest four, the rule is defined as follows; the frequency of movement is defined from the heart rate which means that if the heart rate is fast the frequency will be low, the opposite goes for the low heart rate. As regards the criminality level, in this case, it defines the angle that the movable parts of the surface open. For high criminality we get little angle and for low criminality a big one.
Assembly of all components
After settling down on how the mechanism works with pneumatics, we were directed to design a component that would contain the following characteristics; a movable structure that can cause many different bahaviours, controlled air going in and out, and connection with other components so as to form a surface. In parallel to this process we decided the right materials too. At first we designed and 3d-printed 2 different components working with balloons and latex respectively.
As regards the one that works with latex, it is separated in two parts. The first is the part that is filled with air. Latex is glued on it so as to make the component air proof. As the air comes in, the latex is inflated forming a little bubble that pushes the second (movable) part away. The air comes in through tubes that fill the component with air.
The second component works with a proper balloon that is placed between two tubes and the air would be travelling all the way through the balloon and to the other components. The problem in this case is that the air was not evenly distributed in the components, as the balloons in some cases were more or less stretched, bigger or smaller.
After these two experiments we decided to continue with the latex solution as it is more effective and a lot more controllable.
Our latest component is an improved version of the latex solution. In this case, we have a bigger hole that inflates and only two tubes by which the air travels through all the components. We have started to change the design of the leaf while keeping in mind the body and the behaviour this new texture is going to have. The following videos show how the component is built, how it works and the different behaviours it has when attached to the servo-valve mechanism.
The Pulse Sensor
Since we have decided to use the human body for our experimentation, we want to use it as an input as well, as the factor that that will give form to what we build. In this direction we will use the pulse sensor, a well-designed plug-and-play heart-rate sensor for Arduino. The value of the pulse rate will inform and form the appropriate behaviour.
In our first attempts, we were experimenting with inflatable balloons that would be potentially covered with elastic fabric. With both regular and customized balloons we found difficult to control efficiently the outcome and the transformation that the air can cause. For this reason, we turned to elastic fabrics that have the ability to inflate.
In the first breath of our inflatable project, we have achieved our first target: to control the air that will go and out a balloon, which will eventually cause the behaviours we want. This video shows how you can move parts of a cloth with a pneumatic mechanism. So as to control the air that goes in and out the balloon, we used two valves ( inhaling/exhaling air) which are controlled by two servos respectively (picture). The servos are contolled by an Arduino Uno. For the moment our inflator is a custom made patent, a bike tube inflated by a manual pump.
Pneumatics is a branch of technology that deals with the study and application of pressurized gas to effect mechanical motion.
Pneumatic systems are extensively used in industry, where factories are commonly plumbed with compressed air or compressed inert gases. This is because a centrally located and electrically powered compressor that powers cylinders and other pneumatic devices through solenoid valves is often able to provide motive power in a cheaper, safer, more flexible, and more reliable way than a large number of electric motors and actuators.
We have chosen to use pneumatics because it is a powerful way to make big transformations with a rather small amount of power (compressed air), especially in small scale projects, like ours. On the other hand, having in mind that we work with the human body and a number of components on it, we will potentially have potentially a better design product in terms of the volume needed in comparison to mechanisms that use actuators and servos. The air can be distributed throughout the components through the tubes and in this way perform any behavior we decide that is important for us. In this way we only need to let the air in and out, control the air flow and design an effective solution for the distribution of air.