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| Co-designer |
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| Strain gauge amplifier |
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A device based on the characteristics of a Wheatstone bridge
circuit, whereby the resistances in three arms are reference values,
and the resistance in the fourth arm is provided by a long wire rigidly
attached to a structure such as a bridge span member. As the wire
is stretched, the change in its resistance is represented by a flow of
current across the center of the circuit, providing a realtime measurement
of the subtle differences in the length of the wire, and thus of the structure.
This product needed to be stable across a broad range of conditions
including, but not limited to, variable power source, extremes of ambient
temperature, altitude, and vibration. |
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| Mail Monitor emissary |
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The Mail Monitor System was devised to track the
flow of mail through the Postal network. At several locations within
the post offices, there were stations at which a microwave transmitter
was positioned, in order to interrogate the mail stream as it passed by.
A standard business-sized envelope bearing a letter-slim, unpowered
responder was deposited into the mail system, just as if it had been a
normal letter, but as it passed each interrogation station, it would rectify
the microwave signal it received, use the rectified energy as a power source,
and respond to the interrogation (at a lower frequency) with a unique code.
In this manner, it could be determined when a particular piece of mail
passed a specific station, without any noticeable change in the mail itself.
I assisted with the design and development of the tiny emissary units
which were mailed in the envelopes. |
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| Telephone toll call inhibitor |
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Before the phone systems became as versatile as they are
today, it was difficult for institutions to block calls which incurred
extra charges. Hospitals, correction facilities, schools, and businesses
were eager to alter their instruments so that outgoing calls could be limited
to non-toll connections. Our device was small enough to fit inside
the phone to prevent tampering, and could be "unlocked" by a code, for
use by authorized personnel. |
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| Spectroscopic peak detector |
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This turnkey MIMIC determined the peaks in the output from
a spectrophotometer, by an adjustable algorithm, before recording the data
from the experiment. |
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| Custom marginal punched card |
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At a time when sorting large quantities of data was a physical
act, I redesigned a marginal punch card to adjust and normalize the distribution
of active positions based on letter-use frequencies.
A marginal punch card resembles a common file card except that
it bears holes all around its periphery. Certain holes (for example,
those representing the first three letters of the subject on the card)
are cut away so that there is a path from the hole to the edge of the card.
When a rod is slipped through a hole (or several rods through several holes)
in a stack of the cards, all those cards which do not have that position
punched out remain on the rod, while the target cards fall out of the stack.
The cards could be indexed by several factors, which is difficult to achieve
with a standard filing system. |
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| Stereopret to HP calculator
interface |
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By eliminating tedious transcription, this MIMIC
improved data gathering reliability, efficiency, and effectiveness, while
increasing operator job satisfaction, by directly conveying information
from the stereo image interpreter to the calculator, eliminating the errors
which often accompanied human input. |
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| Thermoelectric Cooling Control
Unit |
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A high power device for dual solid state cooling, designed
to maintain very low temperatures within extremely tight limits.
In one application, it was used to freeze and control the temperature of
soil samples during experimental testing. |
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| Cardpunch to HP calculator interface |
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The electrical environment of the IBM 029 cardpunch was
extremely hostile to delicate semiconductor components. The I/O for
this MIMIC used a large array of reed relays, which when coupled with
the evolution of attrition and replacement, provided a reliable connection
to the 029 for the programmable interface to the Hewlett Packard calculator.
The unit was in use 24 hours a day, 7 days a week, for many years (and
was reported to be still in service the last time I had contact with the
customer), and after an initial few months of replacing relays as they
became damaged, no further components failed. |
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| Multiprocessor control
system for an Analytical Plotter |
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This was a major project which included an extensive retrofit
to an existing device (a number of units were modified, for a variety of
customers), as well as the complete design of a new device to replace the
existing mechanical methods of data gathering.
In the retrofit, expensive mechanical hardware which needed to be maintained
at incredibly tight tolerances was replaced by computer-controlled servo
motors and optical encoders. |
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| Switchable Character Set control
module for TI733 terminal |
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This was my first project as Tarot
Electronics. It was necessary to fit large components into a
very small space, so my novel approach of reducing PC board track real
estate by putting some of the components (memory) on the back of the board,
made it possible to provide this feature for the 733, when all other approaches
had failed. |
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| MIMIC®,
a Mutable InterfaceTM and one-board
computer, with its support modules, including but not limited to memory,
clock/calendar, data acquisition, motor control, and analog I/O. |
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The MIMIC® logo was applied to a variety of custom
interfaces, turnkey systems, avionics, and personal computers which contained
the micro-computer based modules. |
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MIMIC
has its own page. |
| Designer |
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| Video switch |
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| Fluidic amplifier |
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In my third year project, I built a transistor-like pneumatic
device out of aluminum and plastic, and created a number of interchangeable
parts, to measure the characteristics as component sizes and configurations
changed. When I had established sufficient gain, stability, and control,
my device was used as a model by NRC
to produce brass and steel production versions which were put into service.
Similar devices are used, today, in automobiles and aircraft. |
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| Frame time decoder |
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The time and date data from the Hermes
satellite feed arrived at the ground station in a cryptic format which
needed to be converted before being displayed for human interaction. |
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| Character count detector |
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At one time, TI-733 terminals would lose the last character
of every line. By detecting the 79th character, and capturing
the following inputs as they came in, saving them until the carriage return
was complete, the data loss was averted. The challenge was in fitting
the circuit into the tiny space which was allocated for the device, and
in fitting the firmware into the tiny data space which was available. |
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| Computer to plotter data switch |
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| Stepping motor switching module |
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Lots of high current switches, lots of heat sinks, lots
of computer controls. |
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| PDP-8E downgrade modification |
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The original configuration of the Hermes
Ground Station had a number of devices which were designed to depend on
timing signals from inside the pair of PDP8i computers which were originally
part of the facility. When a newer, faster, PDP8e was purchased,
it was discovered that some of the custom designs had incorrectly counted
on undocumented clock signals which were never intended for interfaces,
and which had been eliminated (for many of the operations) in the new computer,
to improve speed. Rather than try to understand all of the legacy
interfaces (in the absence of their designers) well enough to reconfigure
them, I undertook the task of providing the PDP8e with a lobotomy, reverting
its motherboard clock timing to the PDP8i protocol. |
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| Solid state head temperature gauge |
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This design is founded on the temperature characteristics
of a common diode. |
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| Avionic photogrammetric display
generator |
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Integrating data from a number of aircraft sensors, this
device generated a red LED display which was exposed onto the next frame
of film, providing information about the conditions under which the photo
had been taken. This method of locking the orientation, speed,
distance, etc, to the stereo frames as they were exposed, reduced the possibility
of transcription errors. The problem of limited space was solved
by creating a set of interconnected printed circuit boards which
folded into their tiny box like the paper on a Japanese fan. |
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| Washable input device for fish
measurement |
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We were asked to build a computer which would take voice
commands (because the equipment then in service had acquired an unacceptable
aroma), but at the time that task would have been prohibitively expensive,
if it had been possible at all. Instead, I designed a vernier caliper
with a direct input to the computer, a foot switch to activate the data
transfer, and a washable keyboard. |
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| Two dimensional micrometer
data capture device |
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Using optical encoders, with a custom frame and armature,
it was possible to provide data directly from a micrometer to the computer.
A second linear dimension was included.
A third dimension was commissioned from another supplier, but it was
not successful. |
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| MC68000 based module for multiprocessor
applications |
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It is possible and convenient to slave Motorola 68000 series
microprocessors to Intel 8080 series chips, and in this way, each hardware
module can have its own independent processing while being coordinated
with the other hardware in the system. An 8080 can be slaved to a
68000 with somewhat more difficulty.
The Motorola 6800 series microprocessors were not suitable for our
multiprocessor applications, making neither good masters nor good slaves. |
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| Photogrammetric stereo interpreter
motion control system |
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| Inventor |
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| A unique hinge |
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| Tent fly power supply |
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| UNREALTM
a performer servo-system |
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| Fantasy® (patents 1981)
a curved, performer supported keyboard |
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Fantasy
has its own page |
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| MicroTerminalTM
a hand-held data entry device for small computers |
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| BATTMBackloop
Audition for Telerobotics, an auditory substitute for haptic
controls |
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The BAThas
its own page. |
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InchWurmTM
an
improvement to the locomotion method of a CMU
space station inspection robot
346Kb |
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