CHORD: what has changed from the original specs and why

Why the seporte keyboard?

In discusion with various folk it became clear to me that I did not want to make the keyboard integral to the case. Some of the resons for this decision are listed here:

• Climate - I often want the case mouned under clothing for protection from the weather, having the keys on the case mean the case must be on the outside of whatever is worn.
• Adaptability - Integrateing the keys into the case makes the keyboard fixed. Since the user is likly new to chording, the seporate keyboard allows for the user to modify key spacing or shape or greater comfort
• Cost/Time - The case is a rather expensive part of the rig, I forget this as I think of it as something I slam together in the garage but in reality, it takes quite some to make or is an expence to buy. The chorder is something I think most people can make, but by making it part of the case people felt they did not want to risk the case to experiment with by cutting holes in it to make the keyboard. By seporating it from the case I hope people will feel free to experiment. I did make a new keyboard for this project and construction will be detailed later, unorganized photos are avaialble for the curious at http://www.cs.vassar.edu/~priestdo/chordhack/phonerest/

No 32 disk on chip? Nope, this was a misreading on my part. I thought one was included with the kit. It was not, so I am using the hard disk for the system. At some point I would like to add a disk on chip large enough for the base system in order to reap the power savings from the hard disk being able to shut down more of the time.

So Whats is got?

The Charmit case - I designed this case from the ground up to be something the home builder could use to build a wearable. Parts can be made with just a few tools or purchased from Charmed. The case is built with all connectors coming from one surface to facilitate cable managemant on the body. The plans for the case are availble from http://www.cs.vassar.edu/~priestdo/charmit/specs.html

Use of the Charmit power board - The DC to DC power converter circut was not designed just for this contest, like the case I designed it to be of use for general pc104 wearable projects. Plans and part list is available at http://www.cs.vassar.edu/~priestdo/charmit/specs.html

MZ104 the MachZ pc on a chip in pc104 format board - This is the centerpiece of the project. I am enjoying playing with this board. So far the only frustration with it is the hard drive connector. For some reason it had a 40 pin (full size) hard drive connector and the connector is placed on the board in what is for me, a less than ideal location. To go from this board to a standard 44 pin 2.5 inch drive you need a 40 pin to 44 pin adapter. However, in order to get this adapter in line and in the case I chose the following route. First off I made up a short 40 socket to 40 socket cable buy cutting the end off the a conventional hard drive cable (were it spilts off for two drives), then I go to a FLAT 40 to 44 adapter (getting power from the power tap on the Charmit power board). The adapter boards ends in 44 socket and is suposed to go directy in to the pins on the hard drive, but there is not space for this in the case, so I go to a short 44 pin to 44 socket cable that I am getting from Samtec - once I get all the lengths worked out I will post part numbers here.

Doubletalk text to speech board from RC Systems - A dedicated speech output board in pc104 format, low power and able to be modifide for faster speech. Unfortuanly this board is out of stock and while I have the the one I need for this project it is my understanding that RC Systems does not want to make more for small quantity orders. I do not know how large an order they would want before they will make more.

Toshiba 2.5 inch hard drive 8mm high. - Other laptop 2.5 inch drive could be substituted. I have had good results from both Toshiba and IBM drives. While the case can fit taller in order to fit the 40 to 44 pin adapter, I recommed an 8mm - 12mm high drive. In order to reduce power consumption by the hard drive the following power savings steps have been taken (and each entry below needs to have examples and explanations added):

• Mobile Update replaces update - this tip came from the laptop howto
• add "noatime" to /etc/fstab entries - this tip came from the laptop howto
• Set emacs to auto save based on keystrokes, not time

Sony NP-F960 form factor LiIon battery. I have been using these or their predicessor the NP-F950, for some time. However there are now alternatives to getting the Sonys that seem to pack more power into the same size. Charmed is selling these alternative batteries with clips

Chordhack for creation of a chording input system. I have ported the chordhack to the 2.2.19pre17 kernel but there is still a problem with capslock.

Debian potato + 2.2.19 kernel for security and usb support

Emacspeak This software is the key to this porject. Emacspeak is speech output enabled emacs. It is a marvelous peice of work affording the user a full work environment with context sensative speech output.

cell phone for wireless access - I am using a verizon cdma connections for wireless connectivity. This carries a per minute charge but Verizon does have a direct conection to their digital system so you do get an almost instantainious connection established even if the resulting throuput is only 14.4 baud. I am looking forward to trying a usb based 802.11b adapter for wireless connectivity over wireless ether. The bottom line here is you will most likly need some sort of connectivity, your choices with this rig include:

• USB ethernt when not on the go. I have only used this for a short time but so for this works well
• Serial ppp - this is what I am using now
• parallel port - while I have not used this port for connectivity, I know several folks that have used parallel port ethernet connectors with good results.

Lets do it!

From the board to the hard drive

As mentioned above there are three peices needed to connect the hard drive to the MZ104 board. Once I have the correct length cables I will post photos here and sources here.

Build a keyboard

I offer plans for one alternative at http://www.cs.vassar.edu/~priestdo/chordhack/phonerest/. This small keyboard is not as comfortable to type on as its larger cousins but I think it meets some peoples concerns for a less obtrusive keyboard than some of my more ergonoic variations. If however you think you will be a heavy user, I srongly urge you to try one of the designs based on the cherry keyswitches which can be found at http://www.cs.vassar.edu/~priestdo/wearable.pics.html.

Build the hard disk

use the hard disk adapter to connect the hard disk to the MachZ. Connect the two power lines to the screw down power tap on the Charmit power board. Please note and double check the connections to make sure you have connected ground to ground and 5 volt + to 5 volt +. (illustritive photo here...)

Partition and install the OS

Adding the rescue partition

A key feature of this system is the rescue partition. It is a small patition that is normaly not mounted by the system. It is however the default boot partion. Here is how it works: (non tech explanation to go here)

The rescue partition annouces itself over the
doubletalk and informs the user at each of the following steps while it is fixing/checking the system.  

It does an fsck -y on the rest of the system. 

It sets lilo to boot the primary system on next
reboot. (lilo -R primairy)

It offers a 10 second window where the user can prevent the reboot to the primaiy system.

It reboots the system.

The Primary partition sets itself for the next
reboot (lilo -R primairy) as the last step in the
boot process.  If it does not make it to this
step, or if it hangs in the boot process then
pulling the power and plugging it back in will
cause the system to boot the rescue partition.

I have been using this setup for several years
and it gets through the most comon problem
(occotional need to fsck the root system ) nicely
as well as allowing as speach enabled root
session should the need for major repair work
occure.
(/pre)

 Testing the system with the developers kit boards

 
Recompile the kernel
...add double talk support, usb support, usb ether support, usb handspring visor support if you are going to use a visor for a display (as I have been doing),  keyboard kernel hack, support for console on serial port - a config file and more details will be posted here.

Build the Battery Cables
http://www.cs.vassar.edu/~priestdo/battery.clips/

Build the Keyboard Cable
Build the Headphone Cable for the Doubletalk
Build the USB Cables
Modify the face plate of the case for the second USB and the headphone jack
Put the parts in the case
... stand offs screws and spacers from digikey part numbers xxx 
 and here is where all the rest of the documentation goes...