Friday, June 30, 2006

Mobile Computing

Mobile computing is one of those sticky subjects. Modern mobile computing runs around as cell phones and PDAs. Then there's the crazy people working on a "wearable comping" system that keeps them partially in a computer generated world at all times.

I'm not THAT crazy. I look more for something resembling military computing. There when you need it, mostly hidden when not. One thing that popped up recently is a tech outline of a wearable PC. See link here:

Now, I've run across enough hardware to consider how to build one. A base board system would distribute controls as needed. The main CPU would be a Gumstix, with video breakout and some extra IO. I'm hoping they have a lot of breakout of the video and input hardware. This could be hooked into a 2.2" touchscreen TFT screen ($50 from Mouser). The base board also has built in audio connectors. A 400MHz Gumstix running Linux may be powerful enough to run a voice recognition software package, providing hands free access. A subsystem microcontroller would control stuff like LEDs, IO, touchscreen, etc. I'd probably integrate a pseudo-IMU so that motion may be used to do some control, such as a mouse. I might also wire in a glove or something to allow controlled clicking, or move the IMU to the back of the hand there (now there's an idea...)

Depending on size, a LION battery set can be hidden either behind the board or elsewhere (depending on ergonomics and design). Now, final design is that the casing could be made to look rather professional with a vac-formed casing.


Craig Hughes said...

Gumstix does indeed break out all the video and I/O you'll need. You'd probably want to look at our "Audiostix2" daughtercard for the gumstix motherboard, which has a UCB1400 codec chip on it that'll do audio and the A/D stuff for a touchscreen (drivers already there in linux), and has all the LCD signals brought out to easily soldered headers to which you can attach your LCD panel. The PXA's LCD controller is extremely flexible, and can pretty much drive any LCD panel you'll find up to 800x600. There are also a few dozen other GPIO lines which are also brought out as well. GPS module is optional on that board, turning it into the "GPSstix" with barely an increase in size/weight.
As for voice recognition, a user just submitted a command-recognition (not dictation) VR package called CVoiceControl, which is now in the main gumstix software distribution tree, and so easily added to a gumstix.
We don't currently have a LION battery setup, but wiring a standard phone battery to the power inputs should be pretty straightforward; you might need a charging circuit too, depending on whether the battery has one built-in.

SOI Sentinel said...

Thanks Craig. I haven't looked that way in a while, so a few parts are new to me, as are the capabilities. I'll outline a few parts I'd use on this thing (with some specs for the uninitiated).

CPU: Gumstix Connex 400xm-bt. 400MHz, 64MB SDRAM, 16MB flash, and a bluetooth radio for a default comm option.

Expansion 1: NetCF: add a power jack, a CF slot, and an RJ45. While the MMC variant would also be nice, I prefer the CF slot for the added flexibility. I'd probably start with a 4GB CF card for storage.

Expansion 2: GPSStix, the audio and GPS are great. As you pointed out, it'd be simple to provide a lower cost GPS-Less variant with an AudioStix2.

Possible alternate would be a custom board integrating hardware for some of my other addons. A simple tilt controller may be an option. I'd actually like to take some hardware and develop a flex connected access glove based on either some accelerometers or a gyro or two, plus a few located buttons on the fingers to act as activation and click buttons, allowing the hand and wrist to act as a mouse to a forearm mounted system. If not connected, the touchscreen or a few buttons around the screen may be used to navigate, requiring another hand.

We'd also need to build in some speakers and microphones, so a custom audiostix style board might be best.

Now, the LCD I'd chose is a Microtips MTF-T022BHNLP 2.2" QVGA touchscreen. They have a 3.5", but I think the smaller screen would actually work better here. Available from Mouser. $60.

I'd develop my own LION system. I'm just not capable of doing 4 layer boards or large BGA packages :)

I'd probably build the glove around a nice BMX set I have laying about and the case I'd vac-form and build up. Would look pretty nice.

So... full price system would be $170 (Gumstix) + $130 (GPSStix) + $60 (NetCF) + $100 (estimate for the glove controller hardware build) + $40 (long life battery system) + $50 (casing and misc. hardware) + $60 (Microtips Screen)... $610, possibly a bit more for a custom GPSStix replacement. A non bluetooth 200MHz system ($100), cutting out the RJ45 (NetCF to CF $25), GPSStix to AudioStix2 ($40), and glove controller brings the price down to $320 about.

Unfortunately, I'm just not able to afford to pursue either model right now. I have several other projects to work on after I get my house fixed up.

Mike said...

I have given this a bit of thought and came up with a slightly different concept based around public dumb terminal kiosks.

The limiting factor at this point is I/O, both in data entry and in video output.

I think that a wireless display and keyboard connection to a decent resolution and full size mouse/keyboard for your PDA/Cell phone would be the ticket. Imagine sitting down at Starbucks and your phone detected display. The 19" LCD flicks on, showing your cell's desktop. You can check your email, browse the web, videoconference, whatnot, all on a regular sized screen. When you stood up and walked away, the screen goes blank.