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Last Updated: June 02, 2021 01:45 PM

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

Password based circuit breaker -  A circuit breaker protects electrical circuits from damage n case of overload or short circuit.  Its basic function is to detect a fault condition and interrupt current flow.  The system uses an 8 bit microcontroller of 16f877A family.  An EEPROM stores the password and is easily changeable.  The password is entered through a keypad and a relay opens or closes the circuit breaker, which is indicated by a lamp __ Electronics For You

PC-Based Candle Ignitor -  Here’s a PC-based lighting system that lets you light up a candle using matchsticks by just pressing the ‘Enter’ key on the PC’s keyboard.  It is especially useful when celebrating such...__ Electronics Projects for You

PCO billing meter -  The circuit presented here can be used in PCOs for displaying the actual bill.  The comparative disadvantages of the presented circuit are as follows: 1.  The calculator used along with this circuit...__ Electronics Projects for You

Peltier Thermopile Cloud Sensor -  18-Apr-14 -Design News:   Peltier, or Thermoelectric, coolers are a fairly modern device, but the concept of generating electricity with dissimilar metals goes back to Seebeck and Peltier's work in the 1800s.  Modern devices use alternating P and N semiconductor junctions to pump heat from one side of the device to the other __ Gadget Freak-Case #253

Pen FM Transmitter Bug -  Pen FM Transmitter bug projects have been very popular.  The idea of being able to hide a transmitter in a pen is very appealing.  In an effort to reduce the size of this design, we have used surface-mount components.  Firstly, the thought of using the coil in the tank circuit for transmitting RF was a little far fetched, but we used it as an example for those who were interested in experimenting with our circuits. __

People Were Curious About Fred's Feeding Habits -  19-Jul-04 -Design News:   Disinclined to shimmy up tall trees to replenish his bird feeder, Fred devised an electric cable-and-pulley system to reel it in.  Using a modified garage door opener, he controls the motion of the feeder, which travels 50 ft between his house and tree via a single loop of steel cable and series of __ Gadget Freak

Perfect Wake-up Machine Jolts All Five Senses -  17-Aug-09 -Design News:   Here's an alarm clock that clicks on your favorite music, vibrates your pillow, removes your sheets and makes your coffee.  Brian Wagner and his mechanical engineering teammates at Colorado State University  (Matthew Cuff, Ryan Seeboth and Steve Schmitt) devised the perfect wake-up machine.  The alarm __ Gadget Freak-Case #146

Periodically on-off Mosquito repellent -  Here is a circuit that automatically switches on and off the mosquito repellent after preset time interval, thus controlling the release of toxic vapours into the room.  __ Electronics Projects for You

Personal Alarm -  Small, portable, anti-bag-snatching unit; Also suitable for doors and windows control __ Contact: Flavio Dellepiane, fladello @ tin.it

PIC Chip Boosts Four Rockets Skyward -  16-Feb-10 -Design News:   Almost anyone can build a two-stage model rocket, but Joe Peck took a giant step for rocketeers and added four second stages.  Think of them as MIRVs, microcontroller-ignited rocket vehicles.  Shortly after the rocket takes flight, a Microchip Technology MCU detects the absence of a pin attached to __ Gadget Freak-Case #158

Planet Jupiter Receiver -  How would you like to try some basic radio astronomylistening to the bursts of noise originating from the planet Jupiter, or from the Sun? You don't need a lot of fancy equipment to do this, just the simple shortwave receiver described here.  It?s hooked up to a basic dipole antenna  (which we describe as well) and to the sound card in your PC, so that you can print out "chart recordings" of the noise signals.__ SiliconChip

Plant Moisture Monitor -  Originally intended to monitor the moisture in a potted plant, this moisture monitor really shines as a Christmas tree stand water level monitor! A fresh Christmas tree drinks water an annoying rate and bending down under the __ Contact: Charles Wenzel of Wenzel Associates, Inc.

Plant watering timer -  It's time to automate the watering of your garden, balcony, or that azalea in your living room! __ Designed by Manfred Mornhinweg

Plant Watering Watcher -  A flashing LED signals the necessity to water a plant; Very low current consumption3V powered circuit __ Contact: Flavio Dellepiane, fladello @ tin.it

Plants Watering Watcher 2 -  IC1D is a CMOS Schmitt trigger oscillator at about 2KHz.  It starts and continues to oscillate with a supply down to 1.24V  (the lowest output voltage of my LM317 variable power supply) or less;  IC1A is an inverter;  IC1B is a Schmitt trigger NAND gate.  Its output is low only when both inputs are at, or higher than the upper Schmitt trigger threshold voltage.  With 47 ohms or less between the probes, an input is always low, so the output is always high. __ Contact: IQ Technologies

Pneumatics Power Scary Guy -  02-Nov-11 Design News:   Charles Murray   The Scary Guy is an animatronic figure built by the Scare Factory. Bimba supplied components for electronic controls, air cylinders, valves, fittings, and filters to enable the figure to move its upper body independently. Bimba engineers said the pneumatic bill of materials for the Scary Guy amounted to less than $300. __ Video-Gadget Freak

Pocket Size Fume Extractor -  Good things come in small packages! __ Contact: Jameco Electronics

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

Portable iPod charger -  After having to spend far too many bus rides home with an iPod that had a dead battery, I decided to make a portable charger for it.   (this will work with other USB devices too) It's different from the popular "Altoids box" designs because it charges the iPod through the USB, not firewire.  The advantage is that you use less batteries  (5AA instead of 8AA or 2AA and 2 9v) and the voltage remains constant and does not start at 13.8v and then drops down to 10 to 11 volts.   (thats not the right way to charge a $400 mp3 player)  __ Contact: nikosapi @ gmail . com

Portable Weather Station -  20-Aug-15 -Design News:   Matt Todd, Max Beard, and Kyle Roberts are three Mechanical Engineering students from Colorado State University who have designed a portable weather station.  The Portable Electronic Weather Evaluator  (PEWE) is equipped with multiple sensors a barometric pressure sensor; an anemometer for measuring __ Gadget Freak-Case #271

Power Master-Slave Switch -  Video:  This gadget is a master/slave power switch which is used to turn a slave device on  (or off, if so wired) when a master device is turned on. The author has built two of these devices to turn speaker systems on and off with his TV or his laptop computer. It could also be used for lamps or other things __ Designed by Andrew R. Morris, Gadget Freak-Case #195, Design News

Precision Metronome & Pitch generator -  Precision Frequency generator 1 to 999 Hz; Precision Metronome 1 to 999 beats per minute __ Contact: Flavio Dellepiane, fladello @ tin.it

Propane -Oxygen Cannon & Shock Tube Demonstrator -  7-Nov-14 -Design News:   This project is an experiment in generating supersonic shock waves called detonation waves.  Shock tubes are used as research devices primarily to test the effects of detonation waves on different test articles such as the effect of explosives on buildings, vehicles, and even human tissue.  Shock __ Gadget Freak-Case # 265

Protect Your Smarts, Build a Smart Motorcycle Helmet -  10-May-17 -Design News:   Matt Kopper, Karl Akerberg, and Valerie Cochrane __ Gadget Freak

PWM Line-Voltage Interface Brightens Your Outlook -  23-Feb-10 -Design News:   Several of William Grill's designs have included pulse-width modulator  (PWM) circuits that control LEDs.  But what about the control of line-powered lamps and fixtures? You can find several commercial PWM controllers, but build one yourself, save money and learn how to implement a microcontroller- __ Gadget Freak-Case #159

Quick'n'Easy Digital Slide Scanner -  A simple way to copy slides onto your computer's hard drive.  Do you have a large collection of slides which are deteriorating by the day? Are they growing mouldy or becoming discoloured? Then there is no time to waste.  Get them onto your computer's hard drive before it is too late.  This method is very quick, simple and does not require any electronics.__ SiliconChip

Quick-Touch Automated Laundry Chute -  01-Sept-08 Design News:  Just what you always wantedan automated laundry chute. Jitendra Tailor of Winnipeg created a laundry chute that opens and closes on its own. Drop your clothes on the trap door  (built into the floor of an upstairs bathroom) and the door opens, dropping your clothes down to the laundry room __ Gadget Freak-Case #125


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