A Booming Alias
Feedback and Questions
Snapshot of the Bikelab
LED Taillights

ROBERTS' LAW OF APPLIED MOBILE GIZMOLOGY:
    If you take an infinite number of very light things
    and put them together, they become infinitely heavy.

A Booming Alias

Well, this has certainly struck a chord! As of this writing,
367 people have responded to the announcement of reports from
the bikelab. This is gratifying, and a little scary: now my
blithe prediction of weekly publication has to be taken a
little more seriously. <gulp>

You know, there is something subtle about this whole Grand
Turing Machine project that I am just now beginning to
appreciate. I touched on it in issue #1 (where I commented
that I am just project coordinator for the REAL wizardry that
must be credited to industry), and it was brought into sharp
focus by an article in the Oct 1 issue of EDN about Richard
Stallman of the Free Software Foundation. It spoke of the
hacker ethic, which encourages cooperation and free sharing of
information with the general intent of building the best tools
possible, unhampered by legal constraints.

I believe in this, but I've also seen the awesome power of
competition. It therefore seems that the best stance for me to
take in publications about BEHEMOTH is to protect the
intellectual property of my corporate sponsors, but otherwise
disseminate the concepts and design details as widely as
possible -- either for free, or in value-added form via the
<plug>print edition of Nomadness</plug>. Industry has made
this enterprise possible by contributing ideas -- and it's only
fair for me to complete the cycle, so to speak, by freely
sharing information in return.

And this publication is the vehicle for that. Enjoy, and
please feel free to redistribute this without charge and write
with feedback and questions...

Feedback and Questions

This regular column will present a few specific reader comments
in each issue. To maximize your chances of getting a letter
published, please make your questions well-focused (I've had
some that require about 10K of text for a cogent answer). I do
edit for clarity and brevity...

>From Brian Lloyd of Telebit:

Last time I spoke with you, I enquired about sources for
recumbent bikes. I find the riding position on standard safety
bicycles too uncomfortable (I have a neck and back malady that
causes problems with the head-up riding position). I would
like to construct a smaller version of your bike without all
the features you carry. I would probably limit it to a single
processor, cellular phone, and two meters. There has to be a
way for those of us without millions of $$$ to accomplish some
of the same things that you have.

One other item: the product that we (Telebit) have recently
unveiled will be of interest to you. It is an IP router that
establishes its link with the network using on-demand dial-up
links. Imagine that someone in the Internet needs to establish
a session with your bike (mail, transfer a file, etc.). They
simply route the packet to one of our NetBlazers and it calls
your bike via cellular phone. Likewise you can initiate the
connection via CellBlazer from your bike. Imagine having your
built-in SPARCstation on the Sun network wherever you go but
having the phone connection active ONLY when there is traffic
going back and forth.

-- brian@...

Brian,

Wow! I want one. I'm rapidly getting addicted to the Big
Network... these are some pretty powerful tools. They are
changing my expectations about how datacomm from the bike
should work: stopping at the occasional pay phone and plugging
in the cups no longer seems particularly appealing. The
product you describe sounds like pure magic, and the ideal
solution for this nomadic application. Where do I sign? (NOTE
to readers: We have since spoken and this looks like it will
indeed happen... watch future issues for details.)

As to the recumbent, a good approach is to contact Dick Ryan
about the Ryan Vanguard recumbent. It costs about $1,000 and
is one of the best made commercial recumbents I have ever
seen. The company is in Malden, MA.

Two other resources of note are the Recumbent Bicycle Club of
America and the International Human Powered Vehicle
Association. Both have excellent publications.

-- wordy

A brief comment on the bike's TCP/IP link from Courtney Duncan, N5BF:

Yeah, Cellblazer-like things are leaving hams in the dust.
You're going to be able to remotely mount just about anything
in the world just so you can talk to me on e-mail about how to
make an amateur 1200 baud twice-per-day satellite connection
(that will only work after lots of trying).

Hmm.

Responding to my comment about starting the next journey with RAGBRAI
(across Iowa in July), Chuck N6GAL inquired:

Does this mean you're not starting the grand tour from here?
Will there be no opportunity for those of us still chained to
our desks to spend a few days riding with you?

Chuck...

Actually, there will be some kind of shakedown in this end of
the world before July. I rode all the way to Sunnyvale last
week to visit Trimble Navigation and do an open house with
Ampro, and even that short flat ride demonstrated how badly
I've gotten out of shape. I'm planning a one-week loop to
Pinnacles National Monument sometime in the spring, and
everyone interested is invited... I'll post the details to this
alias as they develop. Hope you can come along!

-- wordy

Now a power management question from Larry Fiedler here at Sun:

I understand that you rip out the power supplies on the
computers and use your own +5V supply from the bike. Does this
cause you any problems, or is it as straightforward as I think?
I suppose you need to solder in a power switch. Is there much
voltage level fluctuation, and if so does this ever cause a
problem?

Larry...

Basically correct -- I run a raw +12 (more or less) battery bus
throughout the whole bike, and then spot-regulate with
dedicated DC-to-DC converters tweaked to each load (MAX638 for
most of the 5-volt stuff). It's hardware intensive, but
maximizes conversion efficiency. The switching is all
electronic via FETs, under control of FORTH tasks in the 68HC11
systems. Another benefit of this is minimization of noise
propagation -- trash in one area is not likely to become
global.

-- wordy

Finally, this from Joe Reed, N9JR, somewhere in Wisconsin...

Thanks for issue 1 - it blew me away. Sounds like a ham
dream! Now since you have the HF antenna problem licked, are
you running PacketCluster and have you developed the ability to
QSY to the DX spot frequency? That might make mobile dxing a
bit easier on a busy highway. Depending on the transceiver you
use it should be a fairly simple programming task

-- 73, Joe N9JR

Joe...

<grin> Well, now there's an angle! Actually, I'm not much of
a DX chaser -- my pleasure in ham radio is making friends, and
the frenzy of a pile-up seems to accomplish quite the opposite
if you're not careful. Being on the bike in strange places
might put ME in the hotseat, come to think of it... and an
endless succession of "QSL, you're 5-9 in Kamchatka, QRZed?"
doesn't sound like much fun, especially if there's an
expectation of QSL cards....

Seriously, though -- automatic control of the transceiver (an
Icom 725) is no problem... it all happens via a serial line
reachable through the network by any of the console
processors. I'm sure some interesting applications for that
will develop!

-- wordy

Snapshot of the Bikelab

I've had a number of questions about the project environment
here, and before going into this week's feature tech article I
think a quick description of the lab is in order.

It's wonderful! Sun has provided about 1200 square feet of
windowless lab space in the relatively unpopulated MTV-4, along
with all necessary hooks to the outside world. The windowless
part is not as bad as it sounds -- it keeps me from getting
seduced by sunny days. Lighting is a blazing array of
FLUORESCENTS (inevitably, an acronym: Fiendish Lights,
Uniformly Obnoxious Retina-Eating Soporific Cylinders of Evil,
Noxious, Toxic Substances), though I do have a few normal
lights to soften things -- like now, when I'm bathed in the
glow of a SPARCstation 1+ at 3 A.M., trying to push buttons in
the right order while listening to jazz.

The computer room is a cubicle in the corner, with three
systems -- the SPARC, a Mac SE/30, and a generic 386 DOS
machine. Fortunately, the chair has wheels -- I use all three
machines daily and am wearing a delta-wye-shaped path in the
carpet. A folding futon stashed under one of the worksurfaces
gives me a break now and then.

Next to the office is the machine shop, dominated by Cecil
(Cecil be da' Mill). This is a classic 1960 Rockwell knee-type
milling machine I bought via misc.for-sale, and next to it are
a grinder/sander, vise, and the other tools of a basic
beginning machinist's shop. I try to keep metal bits from
sailing over the partition to mingle with the electronic ones...

Along one long wall of the lab proper are four lab benches,
astrewn with all the usual clutter of hardware hackerdom. Test
equipment -- scope, distortion analyzer, SCSI bus analyzer,
power supplies, and the like -- is scattered around, along with
various laptops and other development tools. A variety of
cabinets and shelving units spill over with inventory and far
too many magazines, antennas lie about on the floor, a
camping-gear area overflows one corner, and in the middle of it
all is a 12-foot BEHEMOTH -- sometimes linked via umbilici with
the benches.

It's quite a playground, but I still have tire itch. 31 weeks!

LED Taillights

One of the classic concerns about bicycle touring, for lots of
good reasons, involves lighting and safety. If you look at the
situation statistically, it's terrifying: even if only one in
every 100,000 drivers runs over you, it's still going to happen
eventually if you spend a few years on the road. It thus makes
sense to make every effort possible to be VISIBLE, and I don't
mean just screwing on one of those dinky commercial bicycle
taillights that runs on a few penlight cells.

My overall lighting system consists of a 4" 20-watt sealed beam
quartz-halogen fixed to the bike, a Night-Sun dual-beam unit on
the helmet (with 8 watt flood and 30-watt spot), a yellow 7"
highway barricade flasher behind the seat, a round bicycle
taillight, and a pair of 2-section taillights on the trailer to
provide steady-on, turn signals, and hazard blinkers. There
are also reflectors all over the place, an orange safety
triangle on the back of the trailer, two gaudy flags, a couple
of utility lights for the operating position, and possibly
front turn signals if I'm feeling ambitious when I re-do the
fairing.

This article is about the taillights... how to make them bright
and reliable while drawing a minimum amount of power from
precious and heavy batteries.

Recent developments in optoelectronics have made this possible
-- with Hewlett-Packard, Stanley,
and Ledtronics offering high-brightness LEDs with intensities
ranging from 3 to 15 candela at 20 mA. Viewing angle is
relatively narrow (typically 7 degrees between half-intensity
points), but otherwise they behave like any other LED, dropping
about 2 volts and getting brighter for a given voltage as the
ambient temperature drops.

Many automakers, including Nissan, are using these for
taillight and high-mounted stop light (CHMSL) assemblies -- for
good reason. Basically, why start with a lot of radiation
(heat) that happens to include some visible light, then throw
away most of the visible stuff to get red? A typical single
taillight bulb, like the GE 1816 I used for 16,000 miles, draws
about 330 mA; a brighter LED cluster draws 50 mA. The choice
is obvious.

BEHEMOTH now carries three LED taillight assemblies. The
simplest one is on the back of the RUMP (the fiberglass
enclosure behind the seat) -- two parallel chains of 7 LEDs
each, packaged on perfboard in a 2.5" diameter Peterson marker
light assembly from an auto parts store (I just clipped out the
original incandescent mounting hardware). Ten of the LEDs aim
straight out through the lens; four aim sideways to increase
visibility from wide angles. The fresnel-like lens adds enough
dispersion to yield a very satisfying and bright light.

The trailer lights are a bit more complicated, and are built
into Peterson PM-13812 clearance lights, designed for two
bulbs. Each .7X1.4" perfboard cluster of 14 LEDs (top steady,
bottom flash) is fixed to the body by Panduit foam mounting
tape and a little spacer of lexan Thermoclear (very light
double-wall glazing), and four wires are routed through the
trailer wall. A clean mounting to the curved trailer surface
was achieved with a gasket of half-inch Poron cellular
urethane, belt-sanded to shape.

Electrically, we now have two LED clusters (each consisting of
2 parallel chains of 7 junctions, totaling 50 mA) in each
trailer taillight, plus the one on the bike. Now what?
Hooking them directly to a lead-acid battery bus would be a
disaster -- voltage varies all over the map with temperature
and charge conditions.

The answer is a small controller board. A major component is a
little DC-to-DC converter (in this case, an adjustable-output
"DC Battery Adapter" made for the laptop market by Product R&D).
I set this to about 13.25 volts, which
remains constant over an input voltage range of 10-15V. It is
turned on via 1N5817 schottky diode switching whenever any
light switch is activated that calls for LEDs (trailer tail,
bike tail, hazard blinkers, or either turn signal).

In the case of steady-on lights, that's all that happens: DPST
light switches source +12 to the supply and ground to the
associated LED cluster. But any of the three blink conditions
power up another part of the board -- a 7555 CMOS timer with
steering logic to let turn signals override blinkers. This is
set to about 1 second with a 50% duty cycle, and yields a nice
stable flash, switching ground to the appropriate LED clusters
via IRFD113 N-channel power MOSFETs in mini-DIP packages. When
a turn signal is active, the flash signal is also passed to a
piezoelectric beeper. (All electronic parts were from Halted
Specialties in Santa Clara).

This circuit was a handy place to control the yellow barricade
flasher, as well. Originally, this light was a product from
Bicycle Lighting Systems of Falls Church, VA (though everyone
seems convinced I stole it from a construction project
somewhere along the way -- I look like a roving hole in the
road), and it came with a little 2-transistor oscillator
board. It worked pretty well, but is old, corroded, and
generally un-hackable -- so the bulb is now driven by the
opposite phase of my 7555 timer, giving the whole system a
nicely coordinated look.

Overall efficiency is excellent. The CMOS is basically free,
and the DC-to-DC converter costs about 260 milliwatts in
exchange for about 1.2 watts to a pair of LED clusters. Not
perfect, but still well below the wasted power in the
incandescent units (about 8 watts per pair). In other words,
we're getting brighter light, better aesthetics, a crisper
blink, and much higher reliability for about 1/6 the power.
Such a deal...


That's it for this week -- I'm trying to keep the length of
these reports under control. This week I'm off to Novato to
pick up a printed-circuit-board milling machine from Instant
Board Circuits, meaning quick-and-hopefully-easy prototypes.

Cheers from the BikeLab!