studiot: April 2009

..direction..... . .. . ....

after due consideration i have decided to try to produce an interface with the heart, one of the most fundamental elements of the living body. i am interested in ways the human body can be used and improved apon with the benefits of new devices and technology.

so, the input energy will be from the beat of my heart. .what intrigues me about the heart particularly are its mystical, rhythmic qualities.

i have chosen to use and manipulte a music video with my heart beat input because i see a natural relationship between elements of the music and the rhythm of the heart.
i had to make a sound song choice to insure the success of the mission. something likely to get the blood pumping a bit. something like 'satisfaction'. ......

...ideas and project innitiation

i thought of making a pair of shoes with motion sensors as an input or a skeletal hand contraption with push sensors. one of the main concerns i had was how to give these devices a bit of character or something the user could identify with. then, i found an old stethoscope!! ..a nice light blue stethoscope. surely most people can relate to something so fundemental and quirky in appearance...sound sensors was the natural choice for use with the stethoscope. a thermo sensor of some sort measuring the users' temperature was another concept but i had to flag that part of the project as heat sensors capable of giving usable, obviously interactive data, were far too expensive (ah the humble dollar-when will we learn?).

i tested two sorts of microphones to see which was most effective; two different brands of conventional sound wave mics, and a contact mic that is more for picking up vibrations in objects

above: stethoscope head, (left)sound wave mic, (bottom)contact mic

below: arrangement/layout concepts

the smaller sound wave microphone was exactly the right diameter to fit inside the stethoscope tubing. unfortunately it fit so snugly that it stopped sound from traveling around inside the stethoscope and the functionality of the tool is all but completely lost.

using the contact mic i was able to pick up an easily decernable heart beat. i used a 'meter' (among many other things) in MaxMSP 4.6 to show innitial live data.

the basic componentry of the first successful device is made from one 3.5mm plug (mono), the contact microphone, and a 1.5 volt battery and battery housing. lots of wire too. the next step was to present my components in an iteresting, erganomic, cohesive way.. ... .but how?

...refinements

to retain the look of the stethoscope i threaded the wiring through its hollow rubber tubing, attaching components in, on and around the original.

i thought the two variations on this idea were unique and interesting but lacked accessability to some extent. also, it wasn't really wearable. i needed to make something that fit snug to the body which would hold the mic and stethoscope head over the apex of my heart. the apex (which is just a smidgen below your left nipple) was chosen as this is a great place to hear a strong heart beat, and because my skin there moves with the beat (i assumed this would help the contact mic to get the best possible signal).

i boosted the input signal by amplifying the mic in sound options. also, had to check DSP status, in options. this gave me much more useful data to use in MaxMSP but left me more prone to getting spikes in the signal. i countered this problem to some extent during the programming stage (in Max) by using object boxes, such as rate, some mathematics and some jimmying of the help patches.

i used an old guitar strap i found -which was made from wetsuit material (so nice and cumfy for the wearer)- to hold things in place. i put some loops of string in to make the strap like an ajustable rubber belt that is worn from right shoulder across the chest, under the left arm and around the back.

i used a drill with a special drill bit to creat a cradle hole that was half of the thickness of the rubber and the same diameter as the back of the stethoscope head. i did this so the head didn't slip out of the strap, and so that it stayed firm above the heart to get optimum results.

above you can see how nicely the battery cowling attached to the strap. it just happened to fit firmly on there, be the same colour, and sit flush to the width of the strap.

final prototype...

the prosthetic device i have created interacts with many elements of body function to act like an activity sensor -drawing data from my heart beat, my lung sounds, external noise (if its loud enough), my voice.

the device plugs into the 3.5mm mic jack point on most computers to interface with selected software.

the long wires have been taped together where possible to minimise mess and the contact points have been soldered into place. this all means the user is able to exert themselves and cause change in the tempo of their heart beat to provide real time, changable data. This data can be used as a variable that when used with certain software packages (such as MaxMSP and Jitter) to manipulate visual and audio outputs.

..patch...

this is the basic patch i used, in MaxMSP 4.6, to interface with the computer (via my prosthetic vitals monitor)...

i looked at -and used parts of- various help patches, tinkered with lots of numbers and variables, and generally bludered my way through this excellent, visual programming software.

i left the patch decorated with portions of failed attempts and experimental trials. i think this adds to the aesthetic qualities of the patch by making it seem a little less square. 3 'jitter' windows are present and are used to show the visual difference the device is making.

...audio tests

during my audio test i seemed to be picking up some signal from my upper body movements and a little bit from my lung sounds. the sounds from my movements even overrode my heart sounds at times when i started to excert myself.

...audio visual tests

with the signal that was coming from my body to MaxMSP, i was able to manipulate visual data as well as speed data from the audio tests. this meant i was able to depict visual representations of the data e.g pulses of red hue as a filter to play a movie through, or, tempo changes that are directly related to the speed of your motion.

i found i had to tweak and alter the program to suit the type of media being output for maximum results. this became a bit of a game of best guess or trial and error at times. this tinkering became a big part of my learning throughout the whole project.

constant refinement and evolution is key!!!

..reflection.... .. .

the final product is cumfy to wear, is still usable to listen to your heart sounds and retains the visual identity of a stethoscope in the final design. this was important because it gives an obvious feature to the device for the viewer, or user, to identify with. also, it reinforced the idea of my device being a listening device, or like prosthetic ears.

it turned out that i was getting data (signal) from a variety of body functions. this was fortuitous and interesting. i would incorporate elements of this into new models and designs

i would like to use bluetooth or some other means of wireless transmission to send information from the recorder device to the relevent computer software. this would give the wearer greater freedom of movement and be cleaner aestheticly.

this product has great potential to be developed as a sporting accessory or a peice of interactive apparel. we could stitch the components and wires for the whole device (including screen and speakers etc) into the fabric of the garment -possibly with a 3D printer of some sort. ....also, i would like to add headphones (possibly wireless) in place of the conventional ear plugs. this would be to allow the user to switch from listening to the selected (interactive) output to the soothing sound of their heart beat or the sounds of the outside world. this would give the user the ability to have a shirt that responds visually and with sound, to the features of their own body.

my interface device is full of possibilities and scope for development. given some funding and time this could produce a popular technology. ...however, we must consider the holistic health of humans as we interface with, and become more reliant upon, technology during our day to day lives. smart, interactive machines... cybernetic beings... new life?

ive seen videos of similar and related apparel ideas. generally, such items have not been very reactive or linked to the body but it is a fun way of presenting a screen on a shirt. i'd rather the next development of this design looks like the screen is part of the material. or possibly i could develop a type of responsive, colour changing fabric as part of this product. we could make garments that are functional, interactive devices as well. even power these by body energy such as movement, or the heart, or laughter, or whatever we need it to be... i guess we'll see.

Labels: heart beat, interface, seamus mccarthy