Yak-2 Design Specification

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$Revision: 1.2 $


This is the (to-be-)completed design specification for the Yak-2. See the hardware design document for the rationale behind these choices, other options, links to manufacturers and distributors, etc.

Components and mounting

Yak-2 mounted in eHolster harness, back view
Components in dotted lines are optional

Right shoulder

3D layout of components on the right side fitted within an eHolster Handheld PC pouch

Diagram notes: PCM-5822 is rotated so connectors face "up", PCMCIA expansion board is bolted on top, voltage conversion board is sandwiched between SBC and battery. The left side of the pouch will be left open for easier battery access, design of battery casing/conversion board remains open. All lengths are in millimeters.

NB: Advantech's chassis will fit inside pouch, but battery must be changed to NP-F550 and cable connectors will be a problem.

Unit Description Size Weight
CPU Motherboard: Advantech PCM-5822 (Cyrix 233) with heat sink
Memory: 64? MB SO-DIMM
CompactFlash: 128? MB flash memory
PC/104: Advantech PCM-3110A/3112 PCMCIA expansion card
Case: Advantech MBPC-200-5822 chassis or custom mount
145x102x30? mm (stack only)
166x114x40 mm (w/ case)
220g (mobo only)
1.3kg (w/ case)
Battery Sony NP-F750 infoLithium (3000 mAh) or
Sony NP-F550 infoLithium (1500 mAh) (already have one for Glasstron)
Custom Yak-2 voltage regulator board
Charger: Sony BC-V500
DC power supply: Advantech PS-50A
71x40x39 mm (NP-F750)
71x21x39 mm (NP-F550)
200g (NP-F750)
95g (NP-F550)
HD Toshiba/ioData 2GB PCMCIA card N/A 55g
Speaker Miniature laptop speaker ? ? g
Total with NP-F750 battery, no case
with NP-F550 battery, MBPC-200-5822 case
Fits in eHolster Handheld PC pouch... if nylon stretches! 196x127x38mm

Left shoulder

Unit Description Size Weight
VGA MicroOptical CO-7 display driver electronics & power supply or
Glasstron PLM-A35 driver & NP-F550 battery
114x89x45mm (CO-3!)
104x53x39mm (PLM-A35 w/ NP-F550)
192g (PLM-A35 w/ NP-F550)
Fits in eHolster PDA pouch
(if top removed! needs to be done for better battery access anyway...)
I/O USB input device storage (mouse, keyboard...) while not in use, accessible with right hand or
Receiver module for wireless input devices
160x60x30mm (TrackMan xmitter)
157x39x36mm (JVC HC-MM55U)
155x46x32mm (JVC HC-MM77U)
149x67x13mm (WristPC)
140x40x40mm (Twiddler2)
93x38x28mm (FinRing receiver)
122g (TrackMan)
75g (JVC HC-MM55U)
72g (JVC HC-MM77U)
110g (Twiddler2)
200g (WristPC)
Fits in eHolster Large Cell Phone pouch
(nylon deforms, so eg. 40x40 should fit in 66x25...I hope...)
Microphone Clip-on microphone (optional)
No separate power supply, please...
Total depending on I/O device N/A 300-500g


Unit Description Size Weight
Display MicroOptical CO-7 clip-on display (640x480 full color) N/A <50g
Headphone Standard small headphone for audio feedback, VoIP, MP3s, etc (optional) N/A Low =)


All cables are packed onto the straps of the eHolster harness (as shown earlier) and laid out like this:

Inter-component cabling schematic
(nowhere near scale, diamonds denote user-detachable connections)

Right to left

The biggie, all the way across the back: That's it. Power is not distributed as display driver has its own power supply. Note that we optimistically assume all input will be through USB. No hub needed: the mobo provides two USB ports, so we run both cables across and provide two jacks so the user can plug in anything they need.

(BTW, I don't do Twiddlers, but if I did I could run the dual PS/2 cable along the back as well. Or use the USB converter.)

Right to audio in/out

Only one channel out is provided, so either we add switch for toggling speaker/headphone (best placed next to speaker?) or run mono left only to speaker, mono right only to headphone. Microphone comes in from other side.

Left to head

Two questions here:

Future expansion

One PCMCIA slot is currently left free and can thus be used for just about anything, eg. networking (IMT-2000, here we come!). Scattering other USB devices along the harness (camera, extra audio toys, etc) is also be possible, switching keyboard/mouse to PS/2 will add a cable but free up a USB port.

Known problems