Human Interface
The first rule to follow when thinking about the details of the shirts operation is that it has to be perfectly usable without the intervention of another computer. So the shirt has to have a user interface of some description, it already has a display but it’s facing away from the wearer, so a button to mirror the image is needed so you can stand in front of a mirror in the morning and set the shirt up. But what if you want to change things during the day, and can’t find a full length mirror, so the image mirror button becomes and image rotate button; first press mirrors, second press flips, third press returns to normal.
That gives the wearer a way of seeing what they are doing, but how do they control the thing? Well mobile phones again provide the answer, what is needed are some directional arrows, and an alphanumeric keypad for data entry. The problem here is that standard button technology can’t be used as it’s far too bulky and would look silly anyway, so another relatively new idea has to be used, fabric circuits. Basically the ‘buttons’ to be embroidered onto the fabric of the collar 1 using conductive thread, and when you touch them you complete the circuit, simple, effective, and already in use, just not very common use.
Or course the collar may turn out to be a really bad place to have the controls, but this is the sort of thing which the only way to find out for certain would be to actually make a few different versions of it and run tests.
Text entry through the alphanumeric pad would occur just like that on a mobile phone, complete with predictive text input to speed things along and with no real limit on storage space a much more complete dictionary can be included than is normally found on phones, possibly even with the definitions still intact.
Processor Unit
Ideally this would be a low power requirement multi-purpose mobile processor, for this application an ARM cored processor seems to be the logical choice.
ARM CPUs are common CPUs for mobile applications, they are designed with low power requirements and the ability to ‘scale’ their clock speed dynamically to meet the demands of the running software. This means that for simple applications the speed, and therefore the power requirements, can be reduced by the software in real-time. This feature also works in the other direction, with the clock speed able to increase beyond the default rating when more power is required of it, with obvious power use increase.
Another advantage of using an ARM CPU the fact that the ARM Assembler code is and open standard, and one that is relatively easy to learn, which means that more adventurous users can create their own unique software.
For the foreseeable requirements of the shirt a default processor speed of ~100MHz should be more than sufficient, as the shirt itself doesn’t have to deal with the processor intensive task of sound, though future Expansion Modules may contain dedicated hardware for sound.
Expansion Port, and Modules
The ethos of this whole design is one which encourages innovation and experimentation, so it makes sense that the hardware of the shirt should include the physical means for the expansion of its own functions. This comes in the form of three connectors, the first is the mini-USB port which is used to connect to a computer allowing the transfer of data to and from the computer, it also supplies power to the shirt charging the battery while connected. The second connector which allows expansion is the SDHC card slot which not only provided expanded storage in the form of SDHC cards which range from 8MB to 1GB and beyond, but can also act as an interface for devices such as Wi-Fi or Bluetooth wireless networking cards originally intended for use with PDAs.
The third connector is the most significant, as unlike the other two it allows for low level, high speed communication with the CPU. This is the Expansion Port (EX-port), and it is the intended means for upgrading the shirt's abilities in ways which software alone cannot. EX modules open the way for displays activated by sound like the visualisations in MP3 playing software, only using actual sounds around the person wearing the shirt. Or motion activated displays using accelerometers (jolt sensors), or direction based displays using a compass module.
Power Source
Here again mobile phone technology makes an appearance. Lithium Polymer batteries, which are found in today’s increasingly power hungry phones, are light, slim, and high powered rechargeable batteries. They provide superior battery life compared to previous battery technologies, at only a fraction of the weight and size.
Medium
Hand drawn image, and digital greyscale image.
Tools
Copic Markers, fine liner pens, pastel, Adobe Photoshop CS, Wacom Graphire A6 Tablet, Adobe Illustrator CS.