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3-M Corp, St. Paul, MN
Developed a short range optical infrared communications link for the fast food industry. Proposed methods for full duplex audio communications within restaurants using optical techniques.

ARS Inc., Denver, CO
Developed an automated automotive starter solenoid tester. System used compressed air and electronic sensors to make sure the solenoids worked properly.

photos of Company Projects

BI Inc., Boulder, CO
Conducted tests and made product improvements on an electronic home incarceration monitoring system using radio linked leg bracelets. Proposed new methods for bracelet anti-tampering.

Bob McPherson, Colorado Springs, CO
Designed a "cord-alarm" which detected when a power cord was unplugged from a wall socket on a critical medical product. Circuit made no direct connection to the power line. Instead, it detected the electric field from the cord. Patent papers being written.


CGH Medical, Inc., Lakewood, CO
Conducted research and designed circuits to detect, count and size air bubbles in blood using ultrasound techniques. Bubbles with volumes less than 1 nanoliter were detectable. Circuit used in CGH's "CARRT" kidney dialysis machine. Designed and built a portable battery powered bubble monitor used by CGH's sales force to show potential buyers the bubble-free nature of CGH's disposable dialysis machine tubing sets. Wrote circuit descriptions for a patent application on the bubble detector system. Received Patent number 5,394,732.

Photos of Company Projects

C.A. Norgren Inc., Denver, CO
Constructed several special automatic test stations and instruments for a variety of solenoid operated air valves. Conducted tests on magnetic latching air valves. Built a latching valve symmetry calibration fixture. Built a special valve electrical to mechanical response time tester. Designed a low volume valve air leak tester. Tester counted air bubbles in a custom water jar sensor.

Certex, Englewood, CO
Evaluated methods to increase reliability of photo sensors used to detect special black marks on money order forms. Proposed using a microprocessor to pulse the sensor LEDs.
Clancy Systems Inc., Denver, CO
Evaluated portable parking ticket printing system. Recommended ways to improve battery powered operating time and RF noise immunity. Also suggested methods for full duplex RF link.


Photos of Company Projects

Cobe Laboratories, Inc., Arvada, CO
Designed and installed several 25KV, 20KHz corona discharge treatment monitoring systems for in-process monitoring of blood oxygenator membrane materials. System used an optical fiber sensor that measured the ultraviolet light emission levels of the corona discharge.

Photos of Company Projects
Conceptual Engineering Inc., Denver, CO
Designed and developed several new products, including cordless telephones, combustible gas detectors, smoke detectors and motion intrusion alarms. Wrote patent papers on intrusion alarm system.

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Colorado Medtech/Rela (Boulder, Colorado)
Designed a lithium ion battery charger for an implanted hearing aid.   The charger used a magnetic induction technique to avoid any direct connection to the implanted device.  Also designed a key fob style device to send control commands to the hearing aid. The complete system is now in clinical trials.

Photos of Company Projects

Cooper Industries, Fail Safe Division, Chicago, IL
Designed family of line powered touch activated switches used in jail lighting systems.

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DNTL Inc., Englewood, CO
Designed an automatic 120vac/240vac power line voltage selection switch circuit. Circuit used to power portable compressor and dental equipment. System used at 1992 summer Olympics.


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Helped develop a complete video interactive archery shooting range system. System projected moving targets onto a fabric screen using a computer, laser disk player and video projector. Reflector tipped arrows and an infrared CCD camera determined where the arrows hit the target. Also developed a similar shooting range system that used infrared laser equipped pistols and rifles and shotguns. Systems launched laser light pulses at screen targets instead of arrows. 300+ installations now installed and operating. Wrote detailed descriptions for a patent application on the techniques used. Patent now pending.
Denver Museum of Natural History, Denver, CO
Fixed several display and sensing problems. One was an ultrasonic system for measuring human height in the Children's museum.
EDN Magazine, Newton, MA
Published several design idea circuits. Miniature low power line powered AC/DC power supply, low frequency C-MOS oscillator that draws 500 nanoamps, under voltage LED flasher, machine vibration triggered hour-meter, battery powered optical interrupter, over-temperature alarm circuit.

Photos of Company Projects

Easter Owens Electric Co., Arvada, CO
Developed a family of touch activated AC and DC electronic switches. Switches were mostly used to control lights and intercoms in jail cells. Designed and developed complete jail door control and monitoring system for Colorado Arapahoe County jail as well as several other jails in Texas, Florida and California.

Electronic Design Magazine, Cleveland, OH
Published several design idea circuits. Charged coupled MOSFET SSR, pulse period to voltage converter, 110db piezoelectric beeper circuit, photographic film infrared filter, 50ua triggered SSR.


Electronic Educational Development Systems, Longmont, CO
Helped develop electronic educational construction kits. Kits taught children about electronics.
Photos of Company ProjectsEquine Services Inc., Boulder, CO
Conducted research and designed instruments for special CCD TV cameras used to identify horses. The camera took digital pictures of the horse's "chestnut" on each of their legs.
Fischer Imaging Corp., Denver, CO
Conducted tests and examined failures of 50 amp, 2KV SCRs used in x-ray power supplies.
Photos of Company Projects

Fisher Technology Inc.,
Littleton, CO

Designed instruments and controls for several multi-phase DC motors. Designed controls for 100 pound 200A DC arc welder and several types of AC generators. Designed a motor performance monitor. The monitor measured motor torque, RPM, HP, AC volts, AC amps and Watts. Helped define new applications for a 7 pound 10HP motor. Motor used in most solar powered electric cars.

Foothills Medical Equipment Inc., Littleton, CO
Designed power supply for oxygen sensor. Sensor used in medical oxygen delivery system.

Photos of Company Projects

Four Winds Energy Systems Inc., Englewood, CO
Designed and developed control and instrumentation systems for variable pitch wind generators. 6KW generator was power line linked and used wind speed information to maintain power control. Also built wind speed/power and electrical power output monitors. Conducted tests at S.E.R.I. wind energy site.


Gates Rubber Inc., Denver, CO
Designed and installed special hand capacitance activated safety switches for battery production lines. System replaced large mushroom switches to reduce arm muscle fatigue.
Photos of Company Projects



Gerry Baby Products, Wheat Ridge, CO
Conducted tests and made improvements on several electronic products made by Gerry.

Gnuco Inc., Boulder, CO
Developed an optical communications system for an IV drip medical product. Battery powered circuit sent drip rate information to central data collector using infrared light pulse techniques.
Graber Design and Control, Golden, CO
Designed special motor controls for a Greyhound bus washer.
HID Corp, Denver, CO
Developed both active and passive Radio Frequency Identification Device (RFID) access control systems. Developed a micro-powered battery powered RFID card reader. One Patent pending.

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Photos of Company Projects



High Precision Devices, Boulder, CO
Designed and built several custom control systems for museum displays. Lizard body heat demo, insect song book, Koosh Ball stepper motor.

Jack Sperling, Inventor
Designed shower water temperature controller.
Lakewood Enterprises, Englewood, CO
Supported electronic circuit for a candy vending machine.
Laser Technology West Limited, Colorado Springs, CO
Designed several automatic control circuits for a diamond impregnated wire saw system. Saw was used to slice sections from semiconductor ingots. System used NEC micro-computer, a LCD display and several stepper motors. System controlled number of cuts and slice thickness.

Photos of Company Projects

Lighthouse Communications Inc., Littleton, CO
Constructed and tested an optical through-the-air communications system with a 10 mile range. Proposed methods and wrote description of a wide area, high speed information broadcasting service. Service would provide terabytes of library type information to subscribers at high data rates. No FCC approval needed.

Lighthouse Publishing Comp., Littleton, CO
Wrote book, "Handbook of Optical Through-the-air Communications". Book provided charts, curves and circuits to maximize link ranges and minimize sunlight interference. Many unique electronic circuits were included.


Markon Manufacturing, John Hodsden
Researched a portable electronic office, including laptop computer, for sales presentations

Midnight Engineering Magazine, Fort Collins, CO
Wrote magazine articles on imagineering and the creative person. Also described a number of futuristic new products and services. Discussed methods for searching for new product ideas.

Photos of Company Projects

Mountain Medical Equipment Inc., Littleton, CO
Developed an oxygen concentration monitor using liquid electrolyte and speed of sound sensors. Supported medical oxygen concentrator product line. Designed custom product test stations. Conducted research on breath inhalation detection for automatic pulsed O2 delivery. Helped develop a bowel evacuation (enema) product. Solved system sensor problems. Developed a method to calibrate a digital thermometer to within +-0.1 C. Developed a way to test pulsed O2 systems using audio speakers.

Mountain States Inc., Aurora, CO
Designed and developed special precision signal processing circuits for a complex seismic data acquisition system using an auto-ranging 18 bit A/D. Multiple geophone signals were conditioned by the circuits using adaptive filtering techniques and linked to a computer for processing.


Photos of Company Projects


Nadac, Stanley Marks
Re-designed electronics for a video tape vending machines

Photos of Company Projects

OEA, Inc., Denver, CO
Constructed many special test stations and special instruments for explosive devices, including initiator testers for Ford and GM airbags. Designed and constructed a custom 400Hz LVDT exciter/demodulator. Designed and constructed explosive flash detector/timer monitors. Monitors measured and tested the delay between primer impact and actual explosion. Designed and constructed a laser welder process controller. Controller used an optical fiber probe to monitor and count laser light flashes during welding. Designed a computer controlled test station to test components used on the Trident missile. Designed and installed a controller for a precision wire welding station. Station measured weld resistance and insulation resistance to 100G ohms.

Ohmeda, Louisville, CO
Recommended methods to drive various laser diodes and improved methods to detect laser light.
Photos of Company Projects


Opton Corp, Boulder, CO
Designed control circuits for a X-ray film camera and a film viewing system. Camera used a high resolution B&W CRT to project full color ultrasound scanned images onto B&W x-ray film using separate red, green and blue images. Viewer combined the three images to form a full color display. Circuit used 68HC11 microcomputer. Several systems being evaluated by Polaroid.

Ortus Industries Inc., Littleton, CO
Designed and constructed prototypes of fiber optic linked instruments including an oscilloscope probe, a remote DVM readout and a thermometer. Conducted tests on atmospheric attenuation of light pulses under various weather conditions. Proposed methods for a 40 mile telemetry link using a xenon flash light source. Proposed uses for nitrogen spark light sources. Uses included optical radar and long range distance measurements.


Photos of Company Projects

Pasar, Inc., Aurora, CO
Designed and developed special circuits for power line wire tracing devices used to find wires buried, bundled together or hidden behind walls. System also worked through metal conduit.

Phase IV Engineering (Boulder, Colorado)Tested methods to transfer electrical power to a pressure, temperature and ID tag circuit, mounted inside a passenger car tire.  The sponsors for the work were Goodyear and Siemens.  Custom integrated circuits now being designed.

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Phonetica One, Inc., Bailey, CO
Developed special electro-static triggered motion detector circuit for use in electronic robotic plush toy. Proposed other uses for electro-static based motion detector.
Point of View Telescopes, San Francisco, CA
Designed an electronic control circuit for a coin operated panorama telescope.
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Popular Electronics Magazine, Farmingdale, NY
Published 1 amp current injector construction project (November 1993 issue). Device used to measure very low resistance using a standard digital multimeter. Unit was powered from two C cells.
Photos of Company Projects


Possum, Inc., Lakewood, CO
Developed a complete anti-carjacking product. 100 systems now installed and being evaluated by Pepsi in New York City. System was featured on a local Denver TV station news report.

Powertex, Englewood, CO
Conducted tests and made improvements on battery chargers for cellular telephone systems.
RMAC, Inc., Arvada, CO
Designed and constructed special digital recording instruments for measuring heavy metal contamination in water samples. Microprocessor based system printed out test results.
Photos of Company Projects


Radio Sign, Tom Gresset, Inventor
Researched endless cassette tape connected to a low power AM transmitter, used to sell homes. AM transmitter had to adhere to FCC regulations. Used loop antenna tuned to 550KHz.


Photos of Company Projects

Sable Instruments, Inc., Boulder, CO
Designed and developed several custom instruments and control circuits for video and photographic medical camera systems. Camera took Polaroid pictures of medial images off a CRT. Developed special video pattern signal generators to test 1000 line resolution CRTs. Developed a RGB exposure timer for a color photographic system that used three B&W CRT images to develop full color.

Spectromed, Aurora, CO
Assisted in the design and testing of infrared LED arrays, used for veterinary medicine. Near infrared light from LED arrays penetrated deeply into tissues to stimulate growth and healing.
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Photos of Company Projects

Spectrum Inc., Wichita, KA
Designed motor control circuits for a motorized garden cart. System used two 24v DC brush motors with PWM controls. Device was featured in "Future Stuff" book.

Starbase Operations
Designed special optical interface and sound generation circuits for a Star Trek souvenir product.

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Sungate Engineering, Littleton, CO
Designed an electronic control system for a battery powered vertical lifting security gate.

Tele-Communications Inc., (TCI), Englewood, CO
Evaluated a special color NTSC video enhancement circuit for use in consumer TVs. Designed and built a prototype circuit to test picture improvements. Wrote detailed report of findings.
Telecommunication Products Inc., Golden, CO
Conducted tests and made improvements on military through-the-air optical communications systems with data rates up to 50Mb/s. Proposed methods to reduce sunlight induced noise.
Top Flight, Inc., Golden, CO
Made improvements on a video camera control system used to take automated aerial photographs.


Photo of Company Project

Wright Arm Technology Inc., Vershire, Vt.
Designed and developed drive servo control circuits for a computer controlled 4 wheel driven/4 wheel steered robotic platform. Designed and developed a control system for a basketball practicing system using a large capacitor discharge technique. System used a very large solenoid to launch the balls. Designed special switch-mode motor controller for liquid helium refrigeration system. System used free-floating vibrating piston to maintain cold temperatures. Researched concept of using liquid air for energy storage.

Last Updated:  Monday, November 22, 2021 02:42 PM

Faraday Capacitance Proximity Touch Switches Six (6) Models Available           Prices           Place an Order           Project Photos

David A. Johnson, P.E.

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Phone:  806-778-8407  Central Time Zone

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