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Circuit Solutions Notebook
Last Updated On:
Friday August 29, 2008
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Latest Technical Challenge Previous Circuits
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Solutions in Progress |
The following are rough ideas that came from website visitors,
from my own needs or purely from my imagination.
- 60Hz Distortion Meter: Design a simple circuit,
which can display the total harmonic distortion of the sine wave on a standard power line.
- Automatic Convenience Store 911 Caller: Would it be
possible to monitor a store clerk’s heart rate and automatically call 911 when the heart rate suddenly jumped? The sudden rate change would be
triggered by a robbery or some very stressful situation.
- Battery Amp-hour Tester: Design a circuit, which can
measure a battery’s amp-hour rating, using either a constant resistance or a constant current load. Equip the circuit with an automatic
voltage cut-off.
- Battery Free Roadside Barrier Flasher: Design a
system that would turn on a bright roadside barrier type flasher. Use super bright white LEDs, a small solar panel and super capacitors.
- Battery Free Walkway Lights: Design a walkway
light that uses a super capacitor instead of a battery to store energy from a small solar panel and use that energy to light a LED or two at
night.
- City Water Tower Ladder Alarm: Devise a method
to detect when a human is climbing on the ladder of a water tower. The device must be free of false alarms due to wind, snow, rain and birds.
- Communications Through Cement Walls: Can an inductive
method be used to send data through a cement wall? This might be helpful for linking some sensors positioned outside of a house to the
inside, without wires and without conventional RF methods.
- DC Motor Brake:
Design a simple circuit that would automatically apply an electrical brake to the motor, when DC power is removed.
- DC to DC Converter for Single 0.5v Solar Cell:
Design a circuit, which can convert 0.5 volts from a single solar cell to say 6 volts.
- Earth Ground Signal Monitor: Could two metal probes
stuck in the ground detect footsteps or some other interesting signals?
- Earthquake Alarm: Can a battery powered circuit be
designed that it would sound an alarm when the building shakes? The device might give the owner a few extra seconds to seek shelter.
- Electrodeless Conductivity Monitor: Devise a
method to monitor the conductivity of a water based fluid without exposed electrodes.
- Electrodeless PH Meter: Is it possible to
design a system, which measures the PH of a fluid, without any exposed electrodes?
- Electronic Delay Circuit for VOX Microphones:
Can an bucket brigade analog delay devices be used to prevent the clipped first syllable of the first word spoken?
- Explosive Detection Using Optical Fluorescence Methods:
Explore methods of detecting explosives using newly discovered optical techniques, which looks for the 705 nanometer signature of explosives,
illuminated with green laser light.
- Fanny Detector For a Computerized Musical Chair Game:
Design a low power circuit, which can detect the fanny of people setting in the chairs.
- Footstep Monitor Using an Optical Fiber: Devise a
circuit, which uses a single length of plastic or glass optical fiber to detect the vibrations associates with human footsteps.
- Freeze Alarm:
Devise a low power system that will sound an alarm inside a house, when the outside temperature is below freezing.
- Freezer Under
Temperature Alarm: Design a low power circuit which will sound an alarm, when the inside temperature of a freezer is above freezing.
- Geophone Footstep Alarm:
Can a battery powered circuit using surplus geophones be designed that can detect human traffic up to 100 feet away?
- Grocery Store LED Sale Flasher Without Batteries:
Could a small solar cell and a supper capacitor be used to keep a device flashing, drawing energy from the lights within the
store?
- Hallway Human Entry Announciator: Design a circuit,
which can be hidden inside a picture frame, which would activate a sound maker, whenever a human would walk by the device.
- Hidden Behind Wall Capacitance Switch: Design a
capacitance activated switch, which can be activated by a hand behind a wall.
- Human Detection Using Big Mirror: Can a full-length
dressing mirror be used to detect a human moving by?
- Human Motion Detection Using Electric Field Changes:
Can changes in the earth’s natural electric field be used to detect human motion?
- Is the Tube Filled with Clear Liquid or Not?: Devise
a circuit that can determine if a one inch diameter piece of clear tubing has alcohol in it or not.
- Jeopardy Game Boxes: Design a system for a
Jeopardy style game to be used in classrooms, which does not require any wires and is confined to only one classroom.
- Long Range Driveway Announciator: Can a laser pointer
be used to detect a vehicle entering a driveway, from 1000 feet away?
- Long Range Light Beam Intrusion Alarm: Devise a
method to detect human traffic moving through a light beam several miles long.
- Long Range Opacity Monitor: Can a system be designed to
monitor the clarity of air over a distance of one mile?
- Long Range Optical Radar Using Nitrogen Sparks: Can
the small but very bright light from a simple spark gap be used to form a long range optical radar system?
- MHD Flow Meter: Would it be possible to use
magneto hydrodynamic methods to measure the flow of seawater through a pipe?
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Miniature Lighthouse Light Simulator: Design a circuit for HO trains models, which flashes an LED in a manner that duplicates the light from a lighthouse.
- Miniature Low Power AC to DC Power Supply: Design a miniature circuit, which can convert 120vac to +5 volts
at a current of 100 milliamps, with full 5KV isolation.
- Multi-LED
Night Light: Design a night light, using up to 30 white LEDs.
- Office Cubical Entry Indicator: Design a simple
battery powered device that would activate a beeper, whenever someone entered an office cubical.
- Open Radio Transmitter Tower Lamp Indicator:
Design a simple circuit that will light and LED light when the circuit does not detect the current to the tower lamp.
- Optical Fiber Coupled DVM Probe: Devise a
system that can use an optical fiber to link a probe to a standard DVM over a distance of 100 feet.
- Optical Fiber Coupled Scope Probe: Design a system,
which can link an oscilloscope to an isolated probe some 100 feet away.
- Optical ID Badge Transmitter: Could an optical
method be used to detect and ID the location of people within a building? Perhaps detectors would be located on the ceilings.
- Optical Through the Air Ethernet: Devise a system
that can link two buildings, separated by 1000 feet, with Ethernet communications, using optical methods.
- Phone Booth Occupancy Light Switch: Devise a
circuit, which can turn on the light inside a phone booth, whenever a human is inside the booth.
- Pigeon Scaring Device, Electronic Scarecrow:
Devise a battery powered system that could be mounted on top of a roof, which would detect and shoo away pigeons.
- Plastic Water Pipe Tracer: How do you find out the
location of sprinkler pipes buried underground?
- Portable Solar Power Vest and Hat: Devise a
vest studded with solar cells and a broad brim hat, which can supply power to portable tools or camcorders.
- Portable Traffic Counter: Devise a simple
method to count the number of vehicles passing a point on a road. The system must be unobtrusive and easy to install.
- Power Line Noise Indicator: Design a simple
device that indicates the amount of high frequency noise that is on a power line.
- Precision 10 Amp AC Current Source: Design a
circuit, which can route a very clean 60 hertz sine wave signal through a low resistance load, while maintaining an accurate 10 amps of current.
The waveform needs to be very clean and free of harmonics.
- Precision Medical Syringe Volume Monitor: Devise a
method to accurately measure the volume of water based fluid inside a 10cc syringe.
- Rain Detector: Design a rain detector, which is not activated by the fluid but actually detects the falling water drops.
- Remote On/Off Control Using Xenon Flash Light Source:
Can a long range remote Controller be designed so light from a xenon flash can turn something on and off?
- Sensitive Average Current Meter: Design a circuit,
which can measure the average current drawn by a circuit, which may draw current in pulses of 50 milliamps for a few milliseconds, every few
seconds.
- Short Range Audio Link Using Magnetic Bubble Methods:
Experiment with some inductive approaches that can send audio information from a transmitter to a receiver, over a range of six feet.
- Short Range Hand Wave Detector: Design a
battery powered circuit, which can turn something on or off, with the wave of a hand over the device.
- Short Range Opacity Monitor: Design a device that
monitors how clear the air is over a distance of 10 feet.
- Simple Portable Radiation Detector: Devise a small
and simple battery powered device that could detect gamma radiation.
- Simple Vehicle Speed Trap: Can a couple cheap
visible red laser pointers be used to measure the speed of vehicle?
- Small Motor Speed and Torque Controller:
Design a circuit, which can control the speed and maximum torque of a small DC motor. Use a method that does not require
any special encoders on the motor.
- Snap Spring Powered RF Transmitter for Garage Door Opener:
Devise a way to use the energy in the compression of a spring, to supply power a low power RF transmitter, which would operate a garage door
opener. Such a device would then not ever require a battery.
- Snow Depth Alarm:
Design a system that would alert a snowplow driver when the snow depth has exceeded four inches.
- Soil Moisture Monitor Using Electrodeless Techniques:
Is it possible to use some magnetic induction methods to measure the conductivity of the soil underground and use that information to determine
if the soil needs more water?
- Solar Insolation Monitor:
Design a circuit, which will monitor the sunlight intensity in watts per square foot.
- Time to Dust
Indicator: Design a battery powered device, which will alert when it is time to remove dust from the surfaces.
- Toilet Flush Counter: Design a simple system, which
can count the number of times a home toilet is flushed each day, week or month.
- Ultra Low
Power Human Finger Detector: Could a slotted or reflective optical
sensors be used in an ultra low power circuit to detect a human finger?
- Ultra Low Power
Latching Relay Circuit: Design a circuit, which can latch and unlatch +5v latching relay from a small 3 volt lithium cell battery.
- Voltage Booster
for Wall Mounted Power Adapter: Design a circuit that will give a
marginal AC to DC linear power supply a voltage boost, so it can maintain regulation at low line voltages.
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