The ability to take credit cards will be very usefull as I do a lot of independent consulting and am lousy at invoicng afterward. I frequently don't invoice for 2 to 6 months after having done the work! With the WearPOS, I will be able to improve my rediculous accounts receivable practices by simply having a representative of client organizations swipe a company credit card through my magnetic reader at the time services are rendered. Furthermore, I will be able to reduce leakage by charging members of government and other theiving organizations for services they were previously able to obtain for free. I could, for example, begin requiring that representitives of the IRS swipe a credit card to purchase ten minutes of my valuable time before agreeing to speak to them. I could require that highwaymen (ie. traffic cops) swipe a credit card to purchase a copy of my signature before agreeing to sign a traffic citation. Perhaps better yet, I could require these highwaymen to swipe a credit card to pay for the service of retransmitting their radar signal off my vehicle. Since they would have already obtained this service, their refusal to do so would, of course, constitute a theft of services, a criminal act forcing me to put my tax dollars to work by involving the police in the matter. :-) Applications of this nature are virtually limitless and there is a myriad of case law to support our right to charge for such things. As a consultant, corporation or other form of business, we have the right to determine what legal services we provide and no individual or organization has the right to abscond with these services for free (ie. to steal them). If an individual or organization does not want to pay for legally offered services, they simply choose not to become a customer (ie. a consumer of those services). That is how it is done. Anything else is illegal and enforcable by law. You wanted to play capitalism, right boys! Well then, let's play. :-)

• Head Mounted Display (HMD) - I bought an M1 Personal Viewer from Liquid Image. It's pretty decent, especially in NTSC mode, but as it does have its limitations, I'm thinking of it as primarily a starter unit. I'd like to get something like a Personal Monitor from AlbaTech or, ideally, an Eyeglass display from MicroOptical. These, however, are considerably more expensive and MicroOptical's eyeglass displays haven't even really reached full production yet; they're still manufacturing these units by hand and it shows in ther price. If prices on the more inconspicuous, higher performance units do not come down soon, I intend to scavenge up a more custom, but probably not much cheaper, solution. For some good starting resources on HMD options, check out this HMD review by Steve Mann, or this display list from the MIT Wearable Computing Page.

  I've also recently obtained an old, junked Sony CCD-F401 Handycam which I intend to try to canabalize the viewfinder from to see how it performs. I'll update this when I have either made it work or destroyed it. :-)

• Input Device - There are many options in this catagory as well, but I chose to buy a combination chordic keyboard and mouse called a Twiddler from Handykey. It looks to be the most convenient, functional and expedient input device currently available for wearable computing. I'll look into the posibility of creating potentially better, custom scavanged devices, voice response systems and nanotech, biological implants for the cerebrum later on.

• Mainboard - PC/104, a small, low power consumption, expandable wintel evolution pioneered by Ampro Computers and well suited for embeded systems, is probably the best current platform for building a wearable computer. A StrongARM based wearable computer would probably be even better due to the excellent performance / power requirement ratio of the StrongARM, but Linux StrongARM support is still in its infancy. I therefore decided to go the wintel route for now, but not via PC/104. Although PC/104 modules are not prohibitively expensive, they're not cheap either, and since I happened across a pile of surplus Epson IM-403 cash register brains containing very highly intigrated, low power consumption (0.5 amps at 24 VDC) wintel boards (about 6 x 4 1/2 inches), I decided to build my wearable computer by canablizing one of these instead. I bought four IM-403 systems (one for the wearable computer and three for other fun) from Timeline for $396.00! They were about $1200/ea. a year or two ago but Epson has apparently moved on to the IM-423/425 models of their IM 4 series POS processors and just liquidated their old IM-403/405 units. They come in very small cases (9 7/8 x 6 5/8 x 3 1/8 inches) with system specifications as follows.
   

  CPU and Memory 32-bit CPU SL enhanced Intel 486SX, 33 MHz processor Power Management Advanced Power Management BIOS controls power management functions for the CPU, hard disk drive, video controller, and I/O controller; offers both standby and suspend modes for optional power savings; functions controlled through the power management utility System Speed Fast and slow speeds available through the Boot Speed option in the System configuration Utility; at fast speed, the processor speed is 33 MHz; at slow speed, the processor speed is 16.5 MHz  Memory Support for one 1 MB, 2MB, 4MB, 8MB, 16MB, or 32MB SIMM, 72-pin, tin-plated, 32-bit or 36-bit, fast-page mode (1 RAS, 2 CAS) 60ns to 80ns; SIMM voltage and bank configuration controlled by jumpers ROM System BIOS (including the System Soft® System Configuration Utility), Advanced Power Management BIOS, and video BIOS located in 256KB flash ROM on system board; 112KB available for a user-defined program Video RAM 512KB DRAM standard on the system board Shadow RAM Shadowing of System and video BIOS ROM into RAM Cache 8KB of internal cache on processor Clock/calendar Real-time clock, calendar, and CMOS RAM contained in the Dallas® DS12885® chip; backed up by a 3 V lithium battery

  Controllers Video Chips and Technologies® CHIPS® 65535 high-speed Super VGA, 32-bit local bus controller; supports advanced power management features, standard video modes in 256 colors for 640 x 480 and 800 x 600 and in 16 colors for 1024 x 768 System Board I/O Standard Microsystems Corporation® FDC37C651 super I/O controller on system board supports up to two serial ports, a parallel port interface, an IDE hard disk drive interface, and one floppy disk drive External I/O Board Standard Microsystems Corporation FCD37C652 super I/O board supports up to two additional serial ports and an OCIA port

  Interfaces Monitor VGA interface for fixed or multi-frequency, monochrome or color VGA monitors built into the system board; 15-pin, high-density D-sub female connector Parallel (LPT1)/OCIA The parallel interface connector can be set to support OCIA or standard parallel through jumpers Serial Four Serial ports; COM1 and COM2 are supported from the I/O controller on the system board while COM3 and COM4 are supported from the I/O controller on the external I/O board; COM2, COM3, and COM4 have 9-pin D-sub male connectors; COM1 is a 26-pin connector providing the interface for the TM printer and DM customer display Keyboard IBM PC/AT compatible keyboard interface built in the system board; PS/2 type 6-pin, mini DIN female connector Open Slot One standard 16-bit, half size [224mm (8.86 inches) by 106.68mm (4.2 inches)] I/O expansioni slot, ISA AT-compatible, 7.2 MHz bus speed, with card-edge connectoor PCMCIA expansion slot One expansion slot for a PCMCIA expansion module supporting two Type I or II PC cards or one Type III PC card; half-pitch card edge connector Speaker Internal; interface on power board; no volume control Floppy disk drive One mount available for an EPSON SMD-1140 3.5-inch floppy disk drive with 720KB or 1.44MB storage capacity Hard disk drive One internal mount available for an MCC standard 2.5-inch IDE hard disk drive (0.5 inch high) with adapter board and mounting bracket; hard disk drive type set automatically in System Configuration Utility (custom types can also be set)

  Batteries Ni-Cd 10.8 V, 500mAh, rechargeable (48 hours); provides approximately one minute backup power in the event of a power failure; accessible with tools Lithium 3 V rechargeable (40 hours) for backing up the real-time clock and the CMOS RAM

  These units don't come with hard or floppy drives. While any 2.5 inch hard drive should do just fine, they take only the special notebook sized floppy drive listed above, an Epson proprietary model (SMD-1140), which is not likely to be as easily obtainable.

  Assuming you're not afraid of a soldering iron, Karl Lunt, who also purchased a couple of these units from Timeline, provides instructions on connecting a regular PC floppy drive to an IM-403 on his Hacking the Epson IM-403 webpages.

  For anyone needing, or just wanting, the original Epson proprietary SMD-1140 floppy drive, I recently located a source for them. A company called Test and Repair Services, aka TRS, has them in stock for about $50 each. I bought four of them, one for each of my IM-403s, since they're such cute, little drives. TRS also has 2.5" hard drives at reasonable prices and were easy to do business with. I'll probably shop them again.

• Hard Drive - 2.5 inch, 12mm, Integral Platinum/1010, model 21010 (3904 Cyl - 11 Heads - 46 Sect. = 1011.4 MB). Voltages: +5V == 0.6 A.

• Wireless Networking - I got lucky in obtaining an Ubiquity 2000 from Grant Taylor for the price of shipping! It was manufactured by Pacific Communication Sciences, aka PCSI, formerly a Cirrus Logic subsidiary. In addition to CDPD, it handles AMPS cellular data/fax/voice and PSTN data/fax/voice. It draws .6 watt, has a built in NiCD battery, is serially connected and weighs 1.8 pounds (with the battery). It's even CDPD 1.1 compliant! Not bad for some postage, eh? Needless to say, Grant is my new best friend. ;-)

I plan to persue IP over AX.25 too, but as I've already got this CDPD hardware and will need an amatuer radio license for that , I think I'll be jacking in via CDPD for the short term.

• Power Supply - Since the IM-403 requires a 24 Volt input and good batteries of this sort are harder to find, I initially purchased sixteen 6 Volt Lithium-Ion battery cells from a Batteries Plus retail store for about $600. They were supposed to have made these cells into four 24 Volt battery packs.  After about a month I called to enquire what was up.  They said they were having trouble obtaining the cells they said they could get when they eagerly took my money. I gave them the benefit of the doubt and remained patient. Well, to make a long , painfull story short, after about six months I told them to either obtain the cells pretty quick or refund my money because six months was long enough to wait. Finally admiting that they couldn't obtain the cells, they refunded my money. That was all fine and well, apart from the fact that I was deprived of earning interest on my $600 for half a year, but I still had no power source for my wearable computer! While the whole Batteries Plus fiasco was going on, Steve Mann had mentioned that custom made Lithium-Ion battery packs might be a bit dangerous as they have a tendency to catch fire and one wouldn't want such a thing strapped to their body during such an occurance. Figuring that if anyone had had experience with catching themself on fire in such a manner, it would certainly have been Steve, I acquiesced to his greater experience and wisdom in the matter and decided against going the custom battery cell route a second time so maybe this whole consumer nightmare was all for the best. :-)

  I had initially wanted Lithium-Ion batteries, but since enough time had gone by that I was already thinking about replacing the IM-403 in favor of something that might be a little better and require less voltage, I compromised and purchased somthing called a Multi-Voltage Powerpac from the Raymond Sarrio company. It weighs 2.1 lbs. and outputs anywhere from 3 to 24 volt DC utilizing various voltage chips. This Multi-Voltage feature enables me to use it with the IM-403 today and almost anything I upgrade it to later on. And if I end up replacing it some day as the primary power source for my wearable computer (which is highly likely), I can use it as a power source for almost any portable electronic device.  It will even work in series with a device's existing internal battery such that the device can then utilize the total capacity of both batteries. It has a Fuel Gage consisting of five lights that indicate how much power is left and comes with an automobile charger, AC wall charger (a solar charger is also available at extra cost) and a nylon carrying case with belt loop and shoulder straps. It uses a ThinLine® battery by Portable Energey Products (PEP) which is a planar-case design, combined with thin metal film technology producing thin, flat, light-weight sealed-lead batteries with performance comparable to that of Nickel Cadmium (NiCd) and Nickel Metal Hydride (NiMH) batteries.

• Miscellaneous - Since the PCMCIA expansion module for the IM-403 is hard to come by (i.e. I have been unable to locate a source for it, though I have managed to ascertain that it's Epson model number is OI-B06), and the IM-403 has a single ISA expansion slot, I bought an ISA PCMCIA expansion card for it from Greystone Peripherals. The card is of the self contained variety where the PCMCIA recepticle is built into it. It is called a Dual Outback GS-120, has a standard Intel i82365SL compatible controller and supports two Type I or II PC cards or one Type III. Although this card regularly lists for $99, I got lucky and bought mine during a huge promotional sale for the obscene price of $25.00! :-)