
---------------------- 
NOTES FROM THE BIKELAB 
Issue #6 -- 1/30/91
by Steven K. Roberts
----------------------

Copyright (C) 1991 by Steven K. Roberts.  All Rights Reserved.

	IN THIS ISSUE:
		Random Commentary on Matters Various
			Handlebars
			Handlebar keyboard
			Seat fabric
			Mobile R&D Lab
			More on security
			One last solar charging tweak
			Wiring harness update
		The emailbag
		CD packaging

	"...as we enjoy great advantages from the inventions of others,
	we should be glad of an opportunity to serve others by any
	invention of our own, and this we should do freely and
	generously."
		-- Benjamin Franklin, upon refusing a patent offered
		by the governor of Pennsylvania for his stove.

Random Commentary on Matters Various
------------------------------------

	This is an intense time.  Overload is a common theme:  the
	bike, that perennial focus of attention supported by
	sponsorship and publicity, sits mostly idle while I work full
	time on sponsorship and publicity.  It is a terrible thing to
	be finite.  Progress is occurring on many fronts, but only a
	few of them result in physical changes to the machine.

	Some of those fronts are pretty interesting, though... and in
	this report I want to bring you up to date on a variety of
	items.

HANDLEBARS

	First, you may recall from issue 3 the mail discussion about
	steering.  The question there was whether to stick with the
	straight bar under the seat or go to a much more elaborate (and
	comfortable, probably) assembly that would be more like tank
	controls -- with an articulated linkage of shafts and bell
	cranks to couple arm motion to a pair of opposing push rods.
	The primary motive was ergonomic, eliminating all twists of the
	wrists while adding more handgrip real estate for controls, and
	it also offered elevated WQ (Weirdness Quotient) at no extra
	charge.

	After having nighmares about the dynamics of emergency braking
	on bumpy roads and other risky situations, we're now back to a
	simpler system.  Dave Berkstresser has completed the mechanical
	design, and the aluminum stock and necessary end mills are in
	house.  Basically, this is an extension of the original
	under-seat steering... but done right.  Handgrips will be
	removable for service, and mount into the tube with expansion
	bolts such that they form about a 45-degree angle with the
	frame and tilt up slightly.  This should eliminate all
	pronation and wrist tension, which have slowed my handlebar
	typing in the past.  A pair of 1616 bearings embedded in the
	pivot assembly should make the whole thing tight and smooth,
	and actuation of the fork will be via half-inch stainless
	tubing and rod ends as before.

HANDLEBAR KEYBOARD

	I still haven't figured out quite how to mold the handgrips,
	but there's one major bit of progress in that department:  the
	"switches."  In the past, I used a variety of pushbuttons,
	rejecting the C&K's for environmental flakiness, trying and
	discarding a few surplus things, and eventually settling on the
	ON buttons used by Hand Held Products in the Microwand (the
	Fed-X bar code scanner).  These worked pretty well, and were
	waterproof.

	What I really need, however, is a software-definable switch.  I
	want to have some hysteresis... but I don't yet know how much.
	I want to have actuation force adjustable to taste.  I'd like
	to be able to experiment with using one for Morse Code (yes, I
	know the computer can do that, but it's fun).  And since the
	bike now has a MIDI system, I need to emulate the flute... but
	I'd like aftertouch information to make it more expressive.

	This is a lot to ask of a pushbutton switch.  But there is a
	solution:  Force-sensing resistors (FSRs) from Interlink
	(805-684-2100, Bill Yates).  Originally developed for music
	keyboards, these are made of two flat polymer sheets with
	interdigitating electrodes on one surface and some kind of
	"semiconductive" material on the other.  The harder you press,
	the lower the resistance.  They come in a variety of sizes, and
	the product line includes linear potentiometers and XYZ
	touchpads.

	The ones for the bike are about a half-inch square (with an
	active area that's half that), and will be bonded to the
	fingertip lands on the molded grip assembly, covered with a
	rubber keycap with just enough mechanical hysteresis to provide
	light tactile feedback.  A scanning A-D converter under control
	of one of the New Micros 68HC11 boards (or, possibly, a local
	PIC processor from Microchip) will monitor the resistances of
	all ten FSRs and pass the information on to the keyboard
	software.  Depending on the application, this will yield a
	character, a macro, a musical note, or anything else that may
	be relevant.  (A friend suggested using the aftertouch
	information to add emphasis...  squeeze hard to capitalize!)
	The nice thing about the whole approach is that it puts large
	unknowns into the TBDWL (To Be Dealt With Later) box (otherwise
	known as software).

	More on that -- and on the new chording scheme -- another time.

SEAT FABRIC

	A new seat panel has arrived, custom-sewn of black nylon mesh
	(Luna-mesh) by someone in Boston.  This has provision for the
	insertion of aluminum rods on both sides, which are then
	grabbed by about 50 cable ties to the aluminum seat frame.
	This method is cheap, easy to install, and quite pleasing to
	the eye.  And the cable ties, which can take 120 pounds each,
	are very reliable... IF black ones are used.  White ones
	degrade and fail from UV exposure within weeks.  I'm using
	Panduit this time around... tensioning them properly with a
	hand-operated GS4H installation tool.  (Panduit makes
	everything for wiring:  catalog via 800-333-4115.)

MOBILE R&D LAB

	This will be the subject of a whole article someday, but I've
	gotten some questions lately about what test equipment I
	carry... and the recent addition of a Fluke 87 Digital
	Multimeter provides the news hook.  A soft pack will contain
	the Createc 10 MHz digital oscilloscope, the Fluke, a logic
	probe, a spectrum probe, Ultratorch butane soldering iron,
	wiring tools, and a large tinkering stock of chips and other
	components.  Since I'm going to soft logic as much as possible,
	I also carry a BP Microsystems device programmer, a Datarase II
	miniature EPROM eraser, development tools for the Microchip PIC
	processors, and as much documentation on microfiche and CDROM
	as possible.  The hardware toolkit is not yet together, but
	includes a Makita battery-powered electric drill (with 12-volt
	charger) and a full suite of hand tools.  Unfortunately, Cecil
	has to remain behind... no room for a 900-pound milling
	machine on the bike.

	This new meter is remarkable.  Accustomed to the DMMs of
	yesteryear that measure AC/DC voltage and current, along with
	resistance, I was hardly prepared for the range of measurement
	tools built into one small rugged instrument.  The 4-1/2 digit
	Fluke 87 has an analog bar graph, performs min/max/average
	recording up to 36 hours, measures frequency and duty cycle,
	determines the forward drop of semiconductor junctions,
	measures capacitors, will display readings relative to a stored
	reading, and has ranges for all the essential measurements that
	almost defy comprehension (in conductance mode, for example,
	you can measure up to 100,000 megohms).  Seriously neat stuff.
	It's about 10 times the size of the teensy Soar meter I was
	planning to take, but has hundreds of times the capability.
	Hey, it's only gravity...

MORE ON SECURITY

	In issue #1 of this series, I mentioned the Alpha microwave
	motion sensor, which is integrated into the support column for
	the big yellow flasher.  That is the "level 1" alert,
	indicating that someone is within about 10 feet of BEHEMOTH.
	Other components are now coming together as well.

	The "level 2" alert is provided by the UNGO Box, made by Techne
	Electronics of Palo Alto (415-856-UNGO).  They did something
	unusual for an automotive product:  designed it for extremely
	low-power operation (I wish car stereo manufacturers would do
	that).  This surface-mount board accepts inputs from two motion
	sensors -- remarkable little units that were well proven during
	6,000 miles on the Winnebiko II.

	Essentially, each sensor is a blob of mercury with a 40 kHz
	field around it.  Any rippling or motion of the mercury yields
	changes in flux density, which are then picked off and filtered
	by sensitive op amps.  A settable threshold level then
	determines whether the disturbance is severe enough to issue an
	alarm.

	On BEHEMOTH, there is a 130 db siren -- but it is mostly useful
	to convince dogs that chasing me is not a good idea (it sweeps
	into the ultrasonic and is seriously obnoxious).  The typical
	response to a motion alert at this level is to speak to the
	perpetrator with the synthesizer while beeping me on the pocket
	pager (or calling me on ham radio) to let me know someone is
	touching the bike.  There will be much more on the psychology
	of BEHEMOTH-protection in a later issue... it gets quite
	amusing.

	The "level 3" security alert indicates that access panels are
	being opened or connectors unplugged.  (There are now
	microswitches on the RUMP and trailer lids, and more will be
	installed as enclosures are completed; loopbacks in all harness
	connectors provide feedback on unplugging.)  Levels 4-6 are not
	yet implemented, but are the seat switch, physical movement of
	wheels or steering shaft angle, and changes in GPS satellite
	navigation coordinates.  This last, without corresponding
	password, is a major red alert and the bike will attempt to
	emulate a 5-alarm fire while taking local steps to make riding
	impossible.

ONE LAST SOLAR CHARGING TWEAK

	You may recall the ongoing commentary about dark current and
	other bugaboos in the power management system -- I took care of
	that problem (while adding another potentially confusing
	"mode") by installing a Solar Disable switch betwen the charge
	manager and the batteries.  During long storage away from
	daylight, this will reduce the power leakage by 5.6 mA.

CABLE HARNESS UPDATE

	Wiring isn't a particularly glamorous part of the system, but
	it sure seems to be one of the major time sinks.  The harness
	was officially begun this week with the installation of an
	enclosed aluminum subpanel on the underside of the port
	RUMP-bay (about axle-level on the rear wheel, just above the
	trailer hitch).  This contains a 61-pin military-style Bendix
	connector for data, a Lemo waterproof RF connector for a remote
	antenna, and a 4-pin automotive trailer connector for the power
	bus.  In addition, there is a rubber-booted toggle switch that
	rearranges the relationship between local battery and load when
	the trailer is disconnected (with trailer, all batteries are
	effectively paralleled and managed as a group; without, I
	bypass all that).

	This subpanel is gooped onto the fiberglass, and a plastic box
	is mounted over it to keep stray DRAMs or tools from falling
	into the pins.

	"Those are the headlines -- now the rumors behind the news..."

The Emailbag
------------

The article on Poor Man's Composites in issue #4 generated considerable
mail, as expected.  Frank Lyon, via the Well, suggested some additional
local sources for materials:

	I really enjoyed your tale of fiberglass fabrication. I've
	built five windsurfers in the last 5 years starting from a
	state of pure ignorance so I've 'been there.' Cardboard sounds
	like a good low-hitec solution!

	Let me pass on a few resource tips:

	You should check out Monterey Bay Fiberglass in Santa Cruz
	(408-476-7464).  They have a complete stock of materials
	including the exotic Kevlar and graphite, and thay can give
	good advice.

	Also check Clark Foam (714-582-1031).  Besides being THE maker
	of surfboard blanks, thay make block and sheet foam, the
	hi-hitec way to do what you did.  And their tech literature is
	good reading!!  Try "SANDWICH CONSTRUCTION FABRICATION
	TECHNIQUES and RESINS, SAFETY EQUIPMENT, PROMOTERS, CATALYSTS,
	ADDITIVES AND MATERIALS GUIDE for some good bedtime reading :-)

	Kevlar has the best impact resistance and toughness of any
	fiber.  You should talk to HEXCEL in Dublin, CA (415-828-4200).
	They weave fabrics like S-Glass, Kevlar & Graphite so thay are
	a primary resource.

	Good luck with your projects!

In response to the piece in issue #5 where I sketched an on-the-road
scenario of life with BEHEMOTH, Ken Okin here at Sun offered a succinct
summary:

	Paradise for the techno-weenie!!!!!

Ken's got me pegged.

And Duncan Elliott from the EE Dept at the University of Toronto asks:

	What kind of trailer brakes do you use?  How do they couple at
	the hitch?  When you're going down hill and using the
	regenerative braking on the front wheel, are you in danger of
	jack-knifing?

Duncan...

	The trailer brakes are not yet implemented... awaiting tests on
	the Mathausers.  The plan is to tie them together at a surge
	linkage in the hitch, unless I can find a safe way to store
	brake-compression energy (not in batteries... they can fail).
	Jacknifing does not seem to be a problem -- I've had the
	bike-trailer combo up to 50.5, and that was with bike brakes
	only.  Of course, they were really lousy brakes.......

CD Packaging
------------

	Music is essential.  During the first trip, I carried an Aiwa
	cassette deck and later a Sony, plugging earphones into my head
	and listening to the same old 12 tapes over and over and over
	(at least when local FM had little to offer).  Occasionally I
	would stay with someone who had a good stereo, and I could
	record over a tape that had become particularly boring.

	On the second trip, it was the same basic problem, though I did
	double the size of my music library.  Still, it was a pain:  I
	had to go into "music mode" to listen to something, blocking my
	perception of other audio sources (including reality) with ear
	inserts and having to stop the bike to change tapes.

	Considering the motivational value of music, I've decided to do
	it right.  BEHEMOTH now has a Sony automotive stereo system
	with AM/FM, cassette, and shock-mounted D-180K CD player.
	There's a pair of 4" Blaupunkt speakers on the RUMP just behind
	my shoulders.  Headphones can be used as an option, but are not
	necessary.  And MIDI, video, Mac Recorder, cellular phone, ham
	radio, speech synthesis, and other audio sources can all be
	mixed under software control with the entertainment audio -- so
	I'm no longer stuck in a mode that cuts me off from
	communication and survival data whenever I need some jams.

	All of which will be discussed in more detail later, but
	there's one problem that concerned me right up front:  having a
	good stereo makes one wish for a good music library, and those
	are bulky.  How many CDs in jewel boxes would I be able to
	carry?  20, maybe?

	The solution is elegant, and anyone interested in portable CD
	use (or software distribution) should check this out.  A
	company in Dublin, Ohio called Univenture produces a product
	called the CD-Viewpak.  It is a soft clear vinyl sleeve, into
	which is bonded a layer of spunwoven polyester much like the
	liner material in a floppy disk.  This protects the active
	surface of the CD while leaving the printed side visible -- and
	the space behind the liner allows room for the insert
	describing the disk (to save weight and space, I just photocopy
	the cover page and leave the booklets and jewel boxes back at
	the base office).  My current library of 40 disks has been
	compressed from 16" of shelf space to 3" in the pack.

	Using a Cannondale racktop pack as an enclosure, the
	CD-Viewpaks will allow me to carry between 100 and 120 disks on
	the bike.  The weight is approximately 1/7 that of jewel
	boxes.  Univenture offers a number of variations on this
	theme:  the packs alone, wallets of 12, boxes of 70, or binder
	systems for shelf storage of a music library (or inexpensively
	shipping CDROMs with documentation).  For more info, contact
	Ross Youngs at 800-992-8262 or 614-761-2669.

Closing Notes
-------------

	That's it for this issue.  As you may have noticed, I missed a
	week:  I've been in a state of serious overload setting up the
	new business structure, trying to get issue 10 of Nomadness
	written, negotiating deals, seeking goodies, and -- oh yes --
	working on the bike.  I did take a much-needed break for a
	camping trip to Pinnacles National Monument, and was reminded
	while clambering over world-class vastness that somewhere under
	all this techno-gizmology are some very deep-rooted motives for
	travel.  Oh yeah... I remember...  As the countdown progresses
	(24 weeks), this becomes critically important.  It goes way
	beyond mere motivation and project management -- this takes
	unwavering passion and obsession...

	Both of which weaken under fluorescent light.

	Cheers from another Sunday in the bikelab!

		Steven K. Roberts 
		Nomadic Research Labs 
		P.O. Box 2390 
		Santa Cruz, CA 95063

		wordy@bikelab.Sun.com (primary internet)
		wordy@cup.portal.com
		GEnie, MCI, or AOL:  wordy (GEnie preferred)

