Paul Schmidt's Engineering Page


Special Feature : Trebuchet construction plans (see below)


Background In Germany, I excelled in technical subjects and took awards and college scholarships upon graduation from high school. The last year I spent in Germany, I began to study electronics, industrial design and manufacturing, physics and computer programming, then continued this curriculum upon moving to Illinois in the mid 1970s, culminating with a degree in Electronic/Electrical engineering. I place great value on the job experience I gained working as an electronics technician while going to school. 

Some Locations

As a professional engineer, I have designed electronic circuits, computer software, control systems, and operator interfaces for industry in many locations around the world. I have also traveled extensively to these locations for meetings, customer training, commissioning and servicing. I have circuits, software and systems operating in every state of the USA, throughout Europe, South and Central America, China, the Philippines and Korea.

Here are photos of two power plants that I have worked on.

Upper right:
A 6 unit (essentially 6 independent power plants side by side with some common auxiliary equipment) coal fired power generating plant in China. I helped design a major system for the first two units, revised and serviced a similar system for the middle two units, and did all electrical and programming design for the same system in the last two units.

Lower right:
Another 6 unit coal fired power plant in southern China, actually on an island near the mainland. The high voltage cables reach the mainland on the sea floor; this might be unique in the world. The view is from the top of a mountain at the opposite end of the island. The plant also has a 2 unit natural gas plant along side, see the smaller stacks. The main plant's 3 stacks are 705 feet tall. The plant is built on land fill created when most of a former small mountain on the end of the island was blasted to rubble.


Some Circuits

As a circuit designer engineer, I always enjoyed working with board-level designs, including the artistic pleasures of circuit board layout. While not at all comprehensive, the photo at right shows some of my favorites (manufacturer names and logos have been blackened out).

Back row:
Left - a two level assembly that combines an analog computer ( ! ), digital logic, power handling interfaces and a switching power supply; this monitored the speed of a giant roll of paper feeding into a printing press and synchronized parts of a splicer that attached the leading edge of a new roll and severed the old roll as it ran out, all on-the-fly at high press speeds.
Center & Right - the operator interface (the back side has LEDs which would be visible to an operator) and control board for a machine that keeps paper aligned as it runs through a printing press; includes an elegant servo amplifier motor control feature.
Middle row:
Left - A custom design job; this is an interface that can be retrofitted into a Moog "Mini-Moog" analog synthesizer, allowing it to be played by a computer via MIDI.
Center & Right - opened and closed views of a piece of handheld test equipment; it connects to test points on the 'splicer synchronizer' circuit board above, and autonomously performs all testing and calibration functions.
Bottom row:
A motor control board and associated machine control board (it piggy-backs the first board) for a more elaborate version of the printing press paper alignment device. The operator interface board above also works with these two.

All assemblies shown here are engineering evaluation examples from equipment that went into service in the mid-1980's, most of which is still in use today. Only the MIDI-to-Moog interface uses a microprocessor.

Computer Designs

I have designed a number of personal computer related devices over the years. The photos at right are for two that I still have examples of.

At left is the prototype of a device I designed for a company that planned to make power line surge protector / noise filters for personal computers. The computer and the protector in question plugged into the output on the front, and the engineers dialed in a noise and/or surge type on the green switch (production models would use a dial operated switch instead), then pushed the red button to initiate the desired glitch. The back side had connectors for data recorders and oscilloscopes. The design used thyristors and coils controlled by line synchronized digital logic.

At right is the prototype of what may well be the first voice synthesizer available for personal computers (no others were advertised at the time the design was done). It was made in kit form and distributed through certain computer clubs in the late 1970's and early 1980s, in versions for the  Commodore computers (PET, VIC-20, C-64), TRS-80, Apple II and early IBM models. One city installed these in their schools, connected to the public address systems, and used them to deliver automated announcements!

Both assemblies shown here are engineering prototypes. 

Engineering as Art

Many engineered objects qualify as art works. This may be due to simple elegance in design, overall aesthetic beauty, or the simply the way in which they draw the eye to their shapes. Here are a few diverse examples.

At upper right:
The Kinzua Viaduct in Kinzua Bridge State Park, Mt. Jewett, Pennsylvania. Roughly 2053 feet long and 301 feet high, it was built by engineer Octave Chanute (later of early aviation fame) in 1882, legs reinforced in 1900. A view through the structure is the image next to the title of this webpage. The railroad bridge was the longest and tallest in the world, and remains the fourth highest in the world today. Photos cannot do it justice; visit it in person - it is beautiful.

At middle right:
The KTHI-TV antenna tower in Blanchard, North Dakota, at 2063 feet  the tallest structure in North America, was built in 1963. It looks small from any kind of distance, with nothing to compare it to. Up close it is huge - I liked the extreme curve of the support cables, not obvious unless looking lengthwise.

A full sized playable harpsichord made entirely from LEGO parts by professional LEGO artist Henry Lim using approximately 100,000 LEGO pieces in four colors (only the strings are non-LEGO).

Eero Saarinen's Gateway Arch, a magnificent monument and arguably the most inspired ever built, was designed in 1947, begun in 1962 and completed in 1966. The 630 foot structure is a tapered catenary curve with a stressed skin construction (like an aircraft fuselage) overlooking the Mississippi River in St. Louis, Missouri.

As of July, 2003, this bridge is no more...see epilogue below



The Münster (German name for a Protestant church building) of Ulm, Baden- Württemberg in southern Germany, is the tallest church building in the world at 528 feet and one of the finest examples of the gothic cathedral style structure. Started in 1377 but not fully completed until 1890, it survived the bombing of WW II. Heaven on earth for the engineer; don't miss the opportunity to get up close and personal while climbing the many hundreds of stone steps to the top of the spire.

Engineering for Fun

Engineering is fun. One thing I get a kick out of is the Medieval Trebuchet (tray-boo-shay), the most feared weapon in the Middle Ages. I have made a couple of small working models, called the WarSerpent and WarWorm.  These titles are humorous nods to an ancient type of musical instrument I play, the Serpent, and in part because the most famous ancient trebuchet was called the WarWolf. The models are easy to build and fun to play with. See the photos to the right and downloadable plans below.

The WarSerpent, a small working model of the famous WarWolf trebuchet, about 1-1/2 feet high at the arm pivot, can hurl rubber balls, hand balls, and similar (soft) objects.

Download the WarSerpent construction plans in Adobe
Acrobat (PDF) format, file size about 2.8Mb

The WarWorm, a subminiature working trebuchet model, about 5" high at the arm pivot, can hurl small objects like marbles, ball bearings, and nuts across the room.


Download the WarWorm construction plans in Adobe
Acrobat (PDF) format, file size about 2.1Mb

for more information on trebuchets, go to

Engineering Books

There are a great many books which appeal to engineers simply because they glorify their type of work and their kind of thinking. Here are just a few.

Nothing Like It In the World : Stephen Ambrose (the first US transcontinental railroad)
Chariots for Apollo : Pellegrino & Stoff (the Lunar Module)
The Rocket Team : Ordway & Sharpe : (rocket scientists from the V-2 thru the Saturn V)
The Evolution of Useful Things : Petroski (how everyday things were invented)
The Rocket Boys : Hickam (how rural boys discovered a love for engineering while building homemade rockets)
Engineers of Dreams : Petroski (how the great bridges were engineered)
To Engineer is Human : Petroski (how spectacular engineering failures improved later successful designs)

Engineering Films

Here are a few movies that just make you feel great being an engineer.


Apollo 13 (it doesn't get any better than this)
The Bridge On the River Kwai (we'll show them who knows how to build stuff right)
Das Boot (when you absolutely, positively have to make something work)
The Edge (desperate men use grass roots engineering to save themselves)
The Englishman Who Went Up a Hill But Came Down a Mountain (who said an ant can't move a rubber tree plant? it's all high hopes...)
Fitzcarraldo (ditto above...let's haul a steam ship over a mountain today)
Flight of the Phoenix (Das Boot with wings)
Red Planet (ditto Apollo to engineer your way off a planet without a space ship)
Night Crossing (ditto Red to engineer yourself across the iron curtain)
October Sky (the film version of the book The Rocket Boys, see above)
Tucker : The Man and His Dream (all good engineers have had bastards squash their efforts at least once, this one's a doozy)

and don't forget:

History Channel's 'Modern Marvels series' (how great big stuff was engineered)

Epilogue on Kinzua 

The State of Pennsylvania was executing a rush program to restore and stabilize the Kinzua Viaduct bridge, after it was closed to train and pedestrian traffic due to rust deterioration. On July 21, 2003, as crews working their way towards the center from both ends labored to undo more than a century of corrosion damage, an F1-class tornado touched down in the valley and plowed into the center of the span. The workers barely escaped with their lives, dodging flying tree trunks and other debris. Unfortunately, the weakest and least-restored part of the structure was the part hardest hit, and it laid down to the west, leaving most of the historic bridge on the valley floor as nothing more than a pile of twisted wreckage.

As of this writing, the state was still evaluating options: rebuild the center of the span, or simply stabilize what is left, or tear down the whole thing.



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Copyright Paul Schmidt 2002, revised February 2007