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opportunist 25

the blatant

by Don Lancaster

Elegant Simplicity

O ne of the goals I have consistently sought out over

and very small size. Perfectly matched to both the user and

the job to be done. Use of the absolute minimum of force

concentration to reliably carry out one well defined task.

While a throwaway item intended for one time use, these

last forever. A classic in every sense of the word.

the years is to develop designs and products which

inherently possess an elegant simplicity . Like many

truly great concepts, elegant simplicity can be hard to pin

down. But you sure know it when you’ve got it.

One clue is when industry insiders end up shaking their

heads in stunned disbelief.

Elegant simplicity combines the best of Schumacher’s

"do more with less" and Buckminster Fuller’s "appropriate

technology". Yeah, Whole Earth Catalog stuff. It goes way

on back to that ancient Ockham’s Razor principle of the

most fundamentally direct explanation often ending up the

most correct. Or Einstein’s "Always seek out the simplest

possible solution – but none simpler" .

Probably the best way we can get a handle on elegant

simplicity is to look at several products and designs that

clearly have it. Here are my selections for a few of the all

time winners…

SCHMIDT OSCILLATOR

What is the simplest possible electronic oscillator you

can build? For square waves, the Schmidt Oscillator wins

hands down. It uses 2-1/6 parts, always self starts, is fairly

temperature and voltage stable, and outputs more or less

symmetric square waves. This dude can be micropower at

low frequencies and drives fairly heavy loads.

The key is to pick any CMOS gate or inverter that has

Schmidt Trigger inputs having hysteresis . One-sixth of a

74HC14 is a good four cent starting point. If a rising input

voltage goes past an upper trip point , the output goes low .

If a falling input voltage goes below the lower trip point ,

the output goes high .

On power up, the capacitor cannot instantly charge, so

the input will stay low, and the output will flip high. This

starts charging the cap, slowly raising your input voltage.

When the input voltage reaches your upper trip point, the

output flips low. Now, the resistor starts discharging the

capacitor towards ground. When it hits the lower trip point,

the process repeats.

The choice of resistor and capacitor value determines the

time constant and thus your oscillation frequency. Start off

with a 220K resistor and a 0.001 microfarad capacitor for

something in the mid audio range. Variable resistors or

switched capacitors can be added to extend the range.

All of which gives us a nearly pure implementation of

integrating a square wave to get a triangular wave and then

comparing the limits of the triangular wave to produce an

inverted square wave.

Self-starting is inherent. The very first cycle on power

up will be longer than the others. Which can be handy for

such things as auto-repeat functions on a keyboard.

More details on Schmidt oscillators can be found in my

CMOS Cookbook .

P-38 CAN OPENER

I consider the P-38 can opener to be by far the finest

invention of the twentieth century. Bar none. Compared to

the P-38 , such utter frivolities as radio, television, autos, or

aviation are not even in the same league. Yes, even Hostess

Twinkies pale by comparison.

For sheer bang for the buck and inherent ergonomics,

nothing can remotely compare. The P-38 opens cans. Any

classic tin can, any time, any place. It runs forever. No

batteries required. Fully portable. Self-protecting. Cost is

zilch. No user manuals or tutorials.

Let’s see what we got here. Two tiny pieces of stamped

steel. One is grooved for extra strength. The blade folds

flat for storage or pops open for use. The first time you see

one, you will swear that it couldn’t possibly work. But it

sure does. The secret is "walking" around the folded rim

present on all classic cans. Your thumb and forefinger form

a double lever that pivots on that rim. With a surprising

amount of force magnification. Probably many tons of

pressure per square inch at the blade edge.

The elegant simplicity here is profound: ultra low cost

January-February, 1994

Midnight Engineering

Copyright c 1997 by Don Lancaster and Synergetics (520) 428-4073 www.tinaja.com All commercial rights and all electronic media rights fully reserved.

nicely oscillating, how do you keep your output amplitude

constant and undistorted?

The key secret is to add some sort of stabilization to

your amplifier. Raise the gain to start, and then carefully

and continuously adjust the gain to hold your desired low

distortion output. Such circuits are called AGC loops, short

for Automatic Gain Control . As a further complication, you

want your AGC loop to only respond to long term changes

and not to those cyclic variations of each individual cycle.

Otherwise, you just may increase, rather than decrease your

distortion through intermodulation.

The traditional electronic solution here is to use a peak

detector, integrator, and variable gain amplifier stage. A

royal mess still today, but a real bear back in 1940 .

Well, Mister Hewlett or Mister Packard (I forget which

one) decided to use elegant simplicity instead. They noted

that a pilot light is a nonlinear resistance . The resistance is

low when cold and higher when hot. Which is why most

light bulbs will burn out on power on. Further, there is a

thermal inertia to a lamp that only allows its resistance to

slowly change at the required subaudio rates.

By using a plain old pilot light as your AGC loop, you

can eliminate any need for anything fancy.

On power up, the bulb is cold and you get lots of gain.

During run time, the oscillator cycles at its normal safe

low-distortion output value. If the gain goes up, the current

through the bulb and its resistance also goes up, lowering

the gain. In a tight self-stabilizing loop.

The rest, as they say, is history.

VORTEX COOLER

This one is nothing but a Tee shaped pipe. Blow air in

the middle arm, and hot air comes out one end and cold air

out the other. To -40 degrees and tons of refrigeration.

With zero moving parts.

Important uses are electronic cabinets, sewing machines,

and general machine shop aps.

Shop air gets blown into the middle arm. This creates an

internal hollow supersonic cyclone that travels at a speed

of several hundred thousand RPM . The cylcone moves to

the hot end, and a fraction of it exits.

Now for the tricky part: The remainder of the cyclone

works its way back towards the cold end, inside the entry

vortex. The velocity is still the same, but the radius is less.

Thus, the angular momentum of the inner vortex has to be

lower than the outside one. But since energy has to get

conserved and since the angular momentum has obviously

dropped, there has to be a net transfer of heat energy from

the inner vortex to the outer one. The result is that the outer

vortex heats, and the inner one cools. Finally, the highly

cooled inner vortex exits via the cold air port.

An optional screw adjustment selects the cold fraction.

Which lets you select your choice of maximum cooling or

minimum temperature.

Two sources of vortex coolers are Vortec and Exair .

DURACELL BATTERY TESTER

H-P AUDIO OSCILLATOR

–

Battery testers can be a real hassle. First, you have to

find a load resistor that is properly rated for the exact cell

or cells you are measuring. You then actually measure the

current or voltage under load and compare this against a set

of design curves. Then you interpret the results.

The Duracell folks came up with a better way. They

have literally printed their battery tester onto the blister

package their cells come in. At stunningly low cost.

A marketing solution that is off scale when it comes to

elegant simplicity. Any five year old can use it.

Here’s how this gem works: A conductive pattern is first

printed that forms a resistor. The resistor value is carefully

matched to the cell being tested. The trapezodial shape of

the resistor is carefully selected so that the power density

changes along its length. As a result, the top of the resistor

gets hotter than the bottom. When connected to the test

battery, a temperature gradient is formed, hot at the thin

top and cooler at the thick bottom.

A temperature sensitive liquid layer has been printed on

top of the test resistor. The transition temperature of the

liquid crystal produces a bright green spot. The fresher the

battery, the higher the spot moves up on the display.

Would you believe that the entire Hewlett-Packard

empire was based on one dimly lit pilot light?

The first H-P product was a low distortion, wide range

Wein Bridge audio sinewave oscillator.

A Wein Bridge consists of a single pole RC high pass

filter in series with a single pole RC lowpass filter. The

gain of this network will be zero for very low or very high

frequencies. The gain will be highest at a frequency where

the time constants match. If the resistors are equal, the gain

at the magic frequency will be 0.33 or one-third. Phase

shift will also be zero at this frequency.

To make an oscillator out of this, you simply place an

amplifier with a gain of 3.0 around the loop.

Whoa, not so fast. How do we get started? You have to

provide a much higher gain for startup. And once you are

Midnight Engineering

January-February, 1994

Copyright c 1997 by Don Lancaster and Synergetics (520) 428-4073 www.tinaja.com All commercial rights and all electronic media rights fully reserved.

NE-2 NEON LAMP

ELEGANT SIMPLICITY RESOURCES

Adobe PostScript

1585 Charleston Road

Mountain View, CA 94039

(800) 833-6687

Dallas Semiconductor

4401 Beltwood Pkwy S

Dallas, TX 75244

(214) 450-0400

Exair

1250 Century Circle N

Cincinnati, OH 45246

(513) 671-3322

GEnie PSRT

401 N. Washington St.

Rockville, MD 20850

(800) 638-9636

Information Storage Dev

2841 Junction, #204

San Jose, CA 95134

(408) 428-1400

Parallax

6359 Auburn Blvd, Ste C

Citrus Heights, CA 95621

(916) 721-8217

Vortec

10125 Carver Road

Cincinnati, OH 45242

(800) 441-7454

Whole Earth

27 Gate Five Road

Sausalito, CA 94965

(415) 332-1716

Back in its vacuum-tube heyday, the nine cent NE-2

neon lamp was by far the most versatile electronic part.

Besides the classic flasher circuit I have shown here, the

lowly neon lamp had an amazing variety of uses.

Stuff like a universal power tester, lightning protection,

surge arresting, lamp dimming, electronic organ tone

generation, bistable and astable flip flops, ultra cheap

voltmeter replacements, twinkle lights, hot-chassis warning

devices, polarity indicators, microammeters, radio tube

filament checkers, long life pilot lights, pulse generation,

electronic switch, threshold detector, ac-dc discriminator,

touch switch, strobe light, synchronizer, radiation detector,

ultraviolet sensor, threshold comparator, voltage regulator,

turntable speed control, reference supply, dc coupler, or a

sawtooth signal source. Plus bunches more.

Basically, you’ve got a small glass tube filled with low

pressure neon gas, supporting two wire electrodes. While

normally an open circuit, the neon ionizes when the supply

voltage exceeded 90 volts. Once ionized, the lamp lights

brightly and conducts heavily. When the supply voltage

under the high current discharge drops below 55 volts, the

lamp will extinguish and the cycle repeat. Only the positive

terminal lights under DC . Both light under AC .

Sadly, the generally lower voltages of the solid state

revolution sidelined the NE-2 into an undeserved early

retirement. Yeah, they still cost less than a dime.

One superb example of elegant simplicity is WPL . An

obscure scripting language for the Apple IIe AppleWriter

word processor written by Paul Lutus. This real gem is a

interpretable language that can automate word processing

tasks. Elegantly and gracefully.

The WPL interpreter was written in a mere 1700 bytes of

lovingly hand-crafted machine language code!

Portions of the general purpose PostScript computer

language clearly offer elegant simplicity. Particularly its

total device independence, its use of procedural character

paths, graceful sparse curves, and powerful dictionary

structures. Plus all the continuous on-the-fly high speed

graphical transformations. Not to mention the power

goodies in level II involving forms, FAX , open font paths,

and outstanding color options.

My own personal favorite elegant simplicity ploy? Way

back when I was in college, I used to consistently get the

highest grades on my lab reports. Mostly because my lab

reports were always thicker than the rest. The key secret to

writing thick lab reports? Thick paper!

I have shown some follow-up names and numbers in the

elegant simplicity resources sidebar. More on PostScript

and such appears on www.tinaja.com .

But what did I miss? Surely you have several favorite

examples of your own. Let’s make a contest out of it. Just

jot down your best shot at elegant simplicity and send it to

me at Synergetics . There will be a dozen or so Incredible

Secret Money Machine II books going to the winners, with

an all all expense paid (FOB Thatcher, AZ) tinaja quest for

two going to the very best of all. Let’s hear from you.

What else?

Let’s see. What else passes our elegant simplicity test?

Vise Grip pliers fer sure. That old plastic nut starter from

Heathkit . Or their integrated circuit extractor that can be

approximated by a bent nail.

I kinda did like those Conanda Effect auto windshield

washers that showed up a way back. Two fixed grooves in

a simple fluidic nozzle that swept the washer glop all over

the glass. Or Volkswagen’s Synchro 4WD van that once

and for all solved positraction problems by its optionally

shoving a locking pin through the differential.

I’m also impressed by those new Analog direct storage

EPROM speech recorders by Information Storage Devices

and Radio Shack . Single chip solutions that eliminate any

need for fancy A/D and D/A conversion. And that Basic

Stamp microcontroller from Parallax .

Or that ultra low cost circuitry used in EKG pulse rate

monitors. A complete micropower short-haul telemetry

system in a cheap throwaway module.

Also by nearly any product that Dallas Semiconductor

makes. Especially their "time in a can" dogtags.

What about the computer languages? Most fail elegant

simplicity and do so abysmally. In fact, one good working

definition of elegant simplicity is What UNIX ain’t .

Microcomputer pioneer and guru Don Lancaster is the

author of 33 books and countless articles. Don maintains a

US technical helpline you’ll find at (520) 428-4073 , besides

offering all his own books, reprints and various services.

Don has a free new catalog crammed full of his latest

insider secrets waiting for you. Your best calling times are

8-5 weekdays, Mountain Standard Time.

US callers only, please.

Don is also the webmaster of www.tinaja.com where a

special area has been set aside for Midnight Engineering

readers. You can also reach Don at Synergetics, Box 809 ,

Thatcher, AZ 85552 . Or email don@tinaja.com

January-February, 1994

Midnight Engineering

Copyright c 1997 by Don Lancaster and Synergetics (520) 428-4073 www.tinaja.com All commercial rights and all electronic media rights fully reserved.

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