Electronic Circuits and electronic circuits, electronic schematics plus an extensive resource for hobbyists, inventors and engineers

DiscoverCircuits.com, has 45,000+ electronic circuits, cross-referenced
into 500+ categories.    We have searched the web to help you find quick design ideas.
We make every effort to link to original material posted by the designer. 
Please let us if you would like us to link to or post your design.

HOME Schematics Index Hobby Corner Dave's Circuits Electronic Resources Contact Info
Imagineering Ezine    Discover Solar Energy Dave Johnson & Associates Faraday Touch Switches



Gadget Circuits
Gadgets:  #'s - C        D - E        G - L        M - O        P - S       
T - Z
 

Last Updated: December 01, 2017 05:04 AM


Links to electronic circuits, electronic schematics, designs for engineers, hobbyists, students & inventors:

Circuits Designed by Dave Johnson, P.E. :

Scare Off Pigeons  -  I have an area on my roof where a large flock of pigeons like to roost.  Their nesting materials and droppings really make a mess.  Often there is enough junk from them that it clogs my roof gutters.  Perhaps one way to scare them away . . . Hobby Circuit designed by Dave Johnson P.E.-April 01, 2005

Security_Gate_Power_Source  -  The circuit that I came up with is shown below.  It uses 5 identical circuits.  Each one is wired in parallel with it assigned 650F super capacitor.  A LM385 provides a 1.  2v voltage reference.  A resistor divider measures the voltage across the capacitor and feeds the voltage to a low power, low voltage op amp.  The output of the op amp drives an n-channel FET.  I designed the circuit for a maximum charge current of 600ma.  This would allow the use of a 10 watt solar panel, if needed, in the future.  Each of the five circuits forms a shunt type voltage regulator, limiting the voltage across each capacitor to about 2.  6v.   . . . Dave Johnson, Lubbock TX  (10/13/2009)-DC Magazine - Issue 3 Nov 2009

Shadow Activated Motion Detector  -  The hobby circuit below works quite well in typical indoor room lighting.  I would not recommend its use in direct sunlight.  Two small PIN photodiodes positioned about one inch apart form a shadow detector.  With no shadow cast on the devices, both device . . . Hobby Circuit designed by David Johnson P.E.-August 21, 2005

Simple Circuit for White LED Night Light  -  This simple circuit is designed to plug into a standard AC electrical outlet.  It uses four super bright white light emitting diodes (LED) in conjunction with a capacitor coupled full wave rectifier circuit . . . Circuit by David Johnson P.E.-July 27, 2003

Slotted Opto-Sensor used in Honeybee Counter  -  I designed a circuit similar to this one a long time ago to help a beekeeper count the number of bees going into or out of a hive.  The low power circuit uses a slotted opto-sensor to detect the passing bees.  The circuit advances an electronic counting . . . Hobby Circuit designed by Dave Johnson P.E.-July 08, 2000

Sound Generator-Clicking  -  Often in computer controlled systems, you would like to generate a “click” sound whenever a button is pressed.  This provides the user with audible feedback that the pushbutton press has been acknowledged.  The two circuits below generate such a sound.  A click sound is generated each time the logic input swings from a logic low to high condition . . . Hobby Circuit designed by Dave Johnson P.E.-January 10, 2009

Safe cigarette lighter power socket -  Cigarette lighter sockets available on the dashboards of some vehicles act as a heat source to light cigarettes.  Besides, these can power electronic gadgets like tablets, laptops, portable video players, MP3 players and cellphones.  Some of these devices can be plugged directly into the cigarette lighter socket, while others may need an inverter  (DC-AC converter) . T.K. HAREENDRAN

Salt Water Battery -  About 13 years ago, I made a salt water battery to operate a single AA battery quartz clock.  It ran for several months until I got tired of adding water to compensate for evaporation.  The batttery consisted of 5 cells each producing about 300 millivolts.__ Designed by Bill Bowden

Sam Shunned Those Ordinary Doggie Toys -  27-Sep-04 -Design News:   Given a close relative with a propensity for locking the keys in the car, James tried a variety of Slim-Jims, Lock-picks, and other tools to gain forcible entry to his own car before he decided to go high-tech.  Fortunately, he drives an older-model Chrysler and was able to wire in parallel to the __ Gadget Freak

SCA Adapter -  For Advertisement Free Background Music on FM.   __ Designed by G.L. Chemelec

Scare Off Pigeons -  I have an area on my roof where a large flock of pigeons like to roost.  Their nesting materials and droppings really make a mess.  Often there is enough junk from them that it clogs my roof gutters.  Perhaps one way to scare them away . . . Hobby Circuit designed by Dave Johnson P.E.-April, 2005

SeaCharger Vessel Crosses Pacific Solely on Solar Power -  16-Sep-16 -Design News:   Elizabeth MontalbanoAn autonomous seacraft has become the first unmanned surface vehicle to successfully cross the Pacific Ocean from California to Hawaii solely on solar power. __ Gadget Freak

Security Robot Roams, Shrieks at Intruders -  18-May-09 -Design News:   Here's a robot that will roam your home or office seeking intruders.  The Searching Security Robot was designed by Ian Smith and his fellow students in a mechatronics' course at Colorado State University.  It sits on motor-powered wheels and its eyes consist of an ultrasonic range finder to keep it __ Gadget Freak-Case #140

Security System Calls Your Cell -  25-Feb-08 -Design News:   Bill Bowden has created a security system that calls you when an alarm is triggered.  You can set it up to indicate intrusion into a door, window, office or pool.  It can also connect to a panic button.  The circuit includes a small PIC microcontroller, an assembly program and a handful __ Gadget Freak-Case #116

Seismic Sensor -  My original "Deer Repellent/ Seismic Sensor" recommended using a speaker with a weight glued to the cone as a vibration sensor  (see bottom of page) but it recently occurred to me that the speaker could supply the mass itself.  By gluing  __ Contact: Charles Wenzel of Wenzel Associates, Inc.

Sensor Signals Water Wasters -  13-Oct-10 -Design News:   Nick Knoll's running-toilet alarm uses a magnetic switch and a floating magnet in the toilet tank to signal when the tank has filled.  A metal bracket holds in place a plastic tube that serves as a guide for a foam float with an attached ring magnet.  A magnetic switch within the tube applies power __ Gadget Freak-Case File #172

Shadow Activated Motion Detector -  The hobby circuit below works quite well in typical indoor room lighting.  I would not recommend its use in direct sunlight.  Two small PIN photodiodes positioned about one inch apart form a shadow detector.  With no shadow cast on the devices, both device . . . Hobby Circuit designed by David Johnson P.E.-August, 2005

Shorts Recharge Your Cellphone on the Go -  12-Jul-13 -Design News:   Elizabeth MontalbanoVodafone UK has teamed up with researchers at the University of Southampton to develop denim shorts and a sleeping bag that can harvest energy from body heat to charge portable devices.  The two items are made of thermoelectric energy-harvesting fabric that reacts with body heat and movement to __ Gadget Freak

Shower Stopper -  The shower stopper is a project suggested by one of the readers of the Technical Library.  His request was for a circuit that would activate a solenoid to shut off the hot water to the shower after a reasonable length of time.  It seems that certain members of his household enjoy long, warm showers.  This circuit is probably sadistic!  The circuit detects when the hot water is turned on in the shower by means of a __ Contact: Charles Wenzel of Wenzel Associates, Inc.

Simple  Key-Hole Lighting Device -  When opening the door of your room in the dark, you may have to spend a few minutes searching for the key-hole.  Here is the circuit of a lighting device that...__ Electronics Projects for You

Simple Circuit for White LED Night Light -  This simple circuit is designed to plug into a standard AC electrical outlet.  It uses four super bright white light emitting diodes  (LED) in conjunction with a capacitor coupled full wave rectifier circuit. . . Circuit by David Johnson P.E.-July, 2003

Simple Circuit metronome using LM1458 -  No circuit description, schematic only__ CdS Electronic

Simple Pressure Alarm Monitors Water and Air -  19-Nov-07 -Design News:   William Grill had a periodic problem with backed-up water in his laundry room.  The laundry tub has a shallow drain that is shared with the kitchen plumbing.  The drain would regularly get clogged with refuse from kitchen disposal debris or laundry "goop." When the drain clogged, water backed up onto __ Gadget Freak-Case #112

Simples enable oscilloscope art -  09/24/13  EDN-Design Ideas Let your inner artist out: Paint electrons in quadrature __ Circuit Design by Lyle Williams

Siren Simulator -  This siren circuit simulates police, fire or other emergency sirens that produce an up and down wail.   __ Contact: Charles Wenzel of Wenzel Associates, Inc.

Sleeping Aid -  Based on electromagnetic-field radiation; Place it under the pillowBuilt-in timer __ Contact: Flavio Dellepiane, fladello @ tin.it

Slotted Opto-Sensor used in Honeybee Counter -  I designed a circuit similar to this one a long time ago to help a beekeeper count the number of bees going into or out of a hive.  The low power circuit uses a slotted opto-sensor to detect the passing bees.  The circuit advances an electronic counting . . . Hobby Circuit designed by Dave Johnson P.E.-July, 2000

Smart Basketball Analyzes Shooting, Dribbling -  19-Mar-13 -Design News:   Charles MurrayA new smart basketball can measure the arc and backspin on a shot, or the speed and force of a player's dribbling.  "Now, when coaches say, 'Your left hand is weak,' they can prove it," Mark Davisson, president of InfoMotion Sports Technologies , told Design News.  "The ball doesn't lie." Known as __ Gadget Freak

Smart Bracelet Keeps Tabs on Your Cell -  10-Jul-14 -Design News:   Elizabeth MontalbanoEarly wearable technology has come in the form of clothing, such as shirts with sensors for monitoring sleep or exercise levels.  But jewelry-inspired technology is starting to emerge as the next innovation in smart wearables.  We told you about Ring , a smart device worn on the finger that can __ Gadget Freak

Smart Glasses Rival Google -  23-Apr-14 -Design News:   Cabe AtwellLumus and eyeSight are giving Google a run for its money.  The technology powerhouses recently revealed consumer-grade devices that offer all the prime functions of smart glasses without the bulk.  Lumus, one of the provides of heads-up display flight helmets for military fighter pilots, has brought __ Gadget Freak

Smart Glasses Track Baseball Fans' Interest in Ads -  4-Jun-14 -Design News:   Elizabeth MontalbanoTechnology-enhanced glasses that track people's eye movements are helping the Cleveland Indians determine fans' interest in signs at the stadium when they attend baseball games.  The ball club teamed with Tobii Technology last year to conduct a study at Progressive Field, the team's home stadium, __ Gadget Freak

Smoking Permitted, but Bring a Roast -  23-Aug-10 -Design News:   Anyone can drop a roast or spare ribs into a commercial meat smoker, but Peter Rauch decided to create an electronically controlled smoker that uses a programmable controller, touch-screen human-machine interface, and a network connection.  Not only will this high-tech smoker control its temperature __ Gadget Freak-Case #170

Snore Alarm electronic Device -  Here I describe a little electronic device that detects snoring.  The principle though very simple is efficient and well protected against false triggerings.  Upon detection, it generates a noisy and painfull alarm.  Just what's necessary to wake up everybody except the snorer.   __ Designed by chabin laurent

Solar Light for a Portable Toilet -  Despite being more expensive than standard permanent outdoor toilets, portable toilets  (Fig.1) have several significant benefits as these are self-contained and can be placed almost anywhere.  These days portable toilets...__ Electronics Projects for You

Solar-Powered Smart Bench Charges Phones, Connects to WiFi -  31-Jul-14 -Design News:   Elizabeth MontalbanoPeople have come to depend more and more on their smartphones, using them heavily throughout the day to stay in touch and browse the Web.  But smartphone batteries haven't necessarily lived up to this demand and often lose battery life throughout the day, sometimes in places without access to a __ Gadget Freak

Solder Fumes Remover -  During soldering, lead fumes are generated, which are toxic.  The flux used for soldering also emits fumes, which again are highly toxic if inhaled in excess.  So it is always better...__ Electronics Projects for You

Soldering Iron Tip Preserver -  Although 60/40 solders melt at about 200°C, the tip temperature of a soldering iron should be about 370°C.  This is necessary to make a good joint quickly without the risk of...__ Electronics Projects for You

Sound Generator-Clicking -  Often in computer controlled systems, you would like to generate a “click” sound whenever a button is pressed.  This provides the user with audible feedback that the pushbutton press has been acknowledged.  The two circuits below generate such a sound.  A click sound is generated each time the logic input swings from a logic low to high condition . . . Hobby Circuit designed by Dave Johnson P.E.-January, 2009

Sound Scanner -  This novel sound scanner sweeps all sound vibrations in its vicinity and converts them into audible beeps.  It can sense sound vibrations up to a distance of 6 metres and can...__ Electronics Projects for You

Space Heater Thermostat -  29-June-12-Design News:  An electronic thermostat that senses actual room temperature.  He tested and tweaked the design to get the proper control range and hysteresis.   __ Designed by Andrew R. Morris, Gadget Freak-Case #218,

SparkFun Inventors Kit Is 'Clever' -  12-Aug-11 -Design News:   Steve Ravet -  blogger Steve Ravet recently picked up a SparkFun inventors kit for Arduino.  Though his preferred development hardware is mbed, he was impressed. __ Gadget Freak

Speed Regulator for Rotary Tool -  microcontroller-based DC motor speed regulator brings control for delicate work.   __ Designed by Andrew Morris' Gadget Freak-Case #226

Spud gun ignitor from a disposable camera -  Since the birth of my web pages, I've had many inquiries about how to make an electronic ignition system from a disposable flash camera.  In response to these requests, I've encouraged people to look into the high voltage flyback system instead, which, I believe is a better system.  But for those of you who are determined to make a camera flash system work, this page is for you.  I was fairly impressed on how easy this system was to put together and its reliability for firing.  It also produces a quite impressive "bang" of a spark! __ Designed by Greg Miller

Spy Ear -  What binoculars do to improve your vision, this personal sound enhancer circuit does for listening.  This light-weight gadget produces an adjustable gain on sounds picked up from the built-in high-sensitivity condenser...__ Electronics Projects for You

Spy Ear-Reverse Engineered Circuit -  This instructable introduces the venerable Spy Ear in details and my way to reverse engineer a circuit. __ Designed by Biotele

Spying on Your Freezer -  7-Apr-08 -Design News:   William Grill wanted to make sure his freezer didn't cut out and ruin his frozen food.  He was concerned that when he traveled, his food could defrost and re-freezethus compromising his frozen steakswithout his knowledge.  So, he developed a gadget that measures freezer temperatures, keeps a __ Gadget Freak-Case #118

Static Charge Monitor -  Yes, you read correctly, it's a ghost detector, assuming ghosts exist and, for some reason, have electric charge.  Ok, this is a changing charge detector.  If a ghost disturbs the electric field in the vicinity of this gadget you will see the results on the LEDs.  Don't hold your breath, unless you wish to become a ghost yourself.  There's a pair 'a normal LEDs that display whether the charge at the antenna is changing in a positive or negative direction  (green vs red) .   __ Designed by Lennie Zink

Steam Generator -  for residential steam shower.  (16f873)  __ Designed by Jon Fick

Steve and Friends Discover that Inventing Can Be Intoxicating -  5-May-03 -Design News:   Steve Rundell and fellow engineering students at Michigan State University never go thirsty, thanks to the ingenious automatic drink-making machine they designed and built.  The contraption allows the "bartender" to select various drink mixtures displayed on an LCD screen.  A controller sends a __ Gadget Freak

Steve Gets His Classical Groove On -  7-Apr-03 -Design News:   He's chillin' with Jam Master B from anywhere in his house, thanks to a Palm Pilot equipped with a radio frequency transmitter that allows him to operate his PC-based MP3 player remotely from up to 100 ft away.  An RF receiver connected to the PC acquires Steve's selections from a database of 4,700 __ Gadget Freak

Steve Often Wondered What It Was Like to Be a Fish -  13-Jan-03 -Design News:   But then he realized he didn't like water.  His fish, however, do.  One problem the pump for the well that supplies water to his home runs even when the pressure fails to build up, posing the risk of pumping the well dry.  To guarantee a steady water supply, Steve designed a control device that shuts __ Gadget Freak

Stirling Prayer Engine -  built with simple parts and runs from the heat of a votive candle.   __ Designed by Bob Blick

Stir's Smart Desk Revolutionizes Office Furniture -  22-Oct-13 -Design News:   Cabe AtwellWhy sit when you can stand? Working at the office or at home while sitting for long periods of time can be detrimental to a person's health  (desks should come with warning labels) .  Research has shown that those who work or play video games while sitting for hours can lead to a host of problems, __ Gadget Freak

Stun Guns 1 & 2 -  For Ammusement only! __ Designed by G.L. Chemelec

Suction cup bracket doesn't consistently suck -  16-Nov-06 -Design News:   Welcome to my new and second blog.  My intention is to identify consumer products that work well or badly,   focusing on design and and quality.  No I am not an engineer, but as I mention in my blog profile, I love mechanical and electronic things.  My experience includes working __ Gadget Freak

Sun-Seeking Sunflower -  It senses where the sun is and automatically turns toward it.  A couple of solar cells power the circuit and driver the motor.__ SiliconChip

Super Rugged Computer-Controlled Tyco Car -  7-Dec-12 -Design News:   Matthew Katzenstein took an electrical car and added a range of control based on robotics. __ Gadget Freak-Case #231

Surround Sound Fun in 3D -  10-Dec-10 -Design News:   After hearing a college lesson on Pierre Schaeffer and his potentiometer d'espace, Raven Sanders, a student of the Lyle School of Engineering at SMU, decided that Schaeffer had the right idea when it came to audio mixinga 3-D approach.  She created a flat touch screen that works through __ Gadget Freak-Case #176

Switches and Hits for Nathan -  17-Feb-11 -Design News:   Mark Rumreich built a puzzle for his nephew Nathan.  After building a small version of the "Nathan," he decided to ratchet up the stakes with the MEGA-NATHAN.  The puzzle has a grid of 4x4 toggle switches on the face of a box.  A puzzle pattern is set inside the box using a matching 4x4 switch grid __ Gadget Freak-Case #181

Syncing Music and Fireworks -  20-Oct-08 -Design News:   Deane Williams fixed up his PC to synchronize fireworks with music.  He used his PC's parallel printer port to connect the circuit controlling the fireworks.  He fanned out the port with a 16-line decoder which allows for up to 225 firing devices.  Since the parallel port is difficult to control __ Gadget Freak-Case #128

   <<<          This is the last page of PS

Gadgets:  #'s - C        D - E        G - L        M - O        P - S        T - Z


HOME Schematics Index Hobby Corner Dave's Circuits Electronic Resources Contact Info
Imagineering Ezine    Discover Solar Energy Dave Johnson & Associates Faraday Touch Switches


 About Us   |  Advertise on DiscoverCircuits.com   |   Report Broken Links  |    Link to DiscoverCircuits.com  |    Privacy Policy


Copyright  January, 1998 - December, 2017     David A. Johnson & Associates.  All Rights reserved. 


 Linking is ALLOWED but COPYING any content or graphics to your web site is EXPRESSLY PROHIBITED.