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Electronic Projects to Build
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Last Updated: October 24, 2017 02:55 PM


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

A 300 MHz  Prescaler & 30 MHz preamp for a Little More Serious Frequency Meter  -  A preamp that drives the CMOS counter input and a divide by 10 prescaler to extend the range __ Designed by Dick Cappels

A Decimal to BCD Decoder -  Miscellaneous:  This is a keypad circuit that will convert the decimal value of any keypad switch - Into its BCD equivalent. __ Designed by Ron J.

A Dual Mode Superhet/Direct Conversion AM receiver for 181.818 kHz Lowfer ATtiny2313, AT90S2313 -  This is a description of an experimental AM receiver for VLF.  it is crystal controlled to receive 181.818 kHz (more or less) and operates as either a single conversion superhetrodyne or a direct conversion receiver.  The bandwidths are expected __ Designed by Dick Cappels

A Field Strength Indicator-Analog only -  The circuit is powerd by a single 1.5 volt AA cell.  The current drain is so small, about 60 microamps, I didn't bother with an on-off switch -i just slip a battery in for the day, and hope I remember to remove it when i'm done.  The supply voltage can be increased up to the breakdown voltage of the transistors to increase the sensitivity, but beware - the sensitivty to thermal drift will increase as well.   __ Designed by Dick Cappels

A Gainclone for the PC Age -  Audio input comes from either the Line-Out of the PC or an external sound card (described later).  A small filter consisting of 680Ω/47pF excludes any RF signals from entering the case.470nF input capacitor should have a high voltage rating since it protects against line voltages being connected to the amplifier, since it is in the signal path it should be a high quality type __ Designed by Malcolm Rix

A Little More Serious Frequency Meter -  Maximum input frequency is specified to be 30 MHz in the multi-chip configuration, and in single-chip configuration, there are both 5 MHz and 10 Mhz versions operating with 10 and 20 MHz crystals, respectively.  All versions have 9 1/2 digit resolution.  I have used __ Designed by Dick Cappels

A Precision Portable Voltage Reference -  it has been said that a man with one watch knows what time it is, but a man with two watches is never sure.    The same can be said for a person who has more than one voltmeter.    in my situation, I have several voltmeters in each of two different locations a third of the way around the world apart.  The best solution would be to send the meters to  NiST traceable calibration labs,  __ Designed by Dick Cappels

A Pretty Good LC Meter Based on an AVR ATtiny2313, AT90S2315 -  Calculates and displays L and C from oscillation frequency using reference components.  No relays, no range switching, a minimum of controls.  And it is pretty accurate too!  __ Designed by Dick Cappels

A Regulated 24 Volt Output, 5 Volt Input DC to DC Converter  -  needed a few milliamps at +24 volts for a varactor bias circuit.  Since my systems approach is still to run all of the power though a 5 volt regulator, this meant that I had to come up with a 5VDC-to-24VDC power supply.  The resulting DC to DC converter and regulation circuit are described here __ Designed by Dick Cappels

A Simple Circuit FM Stereo Transmitter -  (ATTiNY12, ATTiNY25, ATtiny2313, AT90S2313, AT90S232, or nearly any other CMOS microntroller-Yes probably even a PIC !) This project appeared in the December, 2007 issue of infoElektronika Magazine __ Designed by Richard Cappels

A Superhet/Direct Conversion AM receiver for 181.818 kHz  -  This is a description of an experimental AM receiver for VLF.  it is crystal controlled to receive 181.818 kHz (more or less) and operates as either a single conversion superhetrodyne or a direct conversion receiver.  The bandwidths are expected __ Designed by Dick Cappels

AC/DC Bike-Powered Generator System -  An exercise bike is fitted with a permanent DC magnet motor, which, charges a 12VDC lead-acid automotive battery.  This battery can be used to directly drive DC loads or can be fitted with an AC inverter to drive regular house-hold loads.  The system is interfaced through the PC to allow data-logging and monitoring of both instantaneous current, voltage and power along with accumulated power.   __ Designed by Greg Miller

ADSL_Splitter_Sharing_Adapter -  When the telephone installer said I would have to use an ADSL splitter on every telephone in the house, I said "Uh huh, " but I had something else in mind.   __ Designed by Dick Cappels

AIU: Analog Interface Unit -  if you need to add simple data acquisition capabilities to your PC, n look no furr than Analog interface Unit.  The Analog interface Unit (AiU) is a simple circuit that connects to a PC parallel port, and allows you to sample and output 8-bit analog signals under software control __ Designed by David L. Jones

Alphanumeric LED Display Project -  A phenomenal 256-diode ROM acts as a character generator for a two-digit hexadecimal display.   __ Contact David Cook

Analog Comparison, Digital Result -  Comparators are very useful for comparing two analog voltages and providing a digital result.  in this case, if the light source is dim, a red LED is enabled.  if the light source is bright, a green LED is enabled.  However, once comparators are understood, they can be useful for driving small robots or helping a microcontroller.   __ Contact David Cook

Anti-Carjack System -  Consider this: A criminal stops your car by force and you are left with no option but to surrender the car.  The criminal drives away your car, but about 60 seconds...__ Electronics Projects for You

Appetizer Robot -  This solar-powered robot is built with a BEAM design.  Small dc motors are driven by a capacitor and steered by photodiodes.  Photographs, links, a video, and a schematic are provided.   __ Contact David Cook

Arduino Experimenter Kit -  Embark on a fun-filled frenzy of electromechanical experimentation. __ Contact Jameco Electronics

ATtiny12 Fuse Restorer -  This restores the fuses in an ATtiny12 via High Voltage Serial Programming.  Plug an ATtiny12 into the 8 pin socket and hold down "GO! " button.  The LED will come on at the end of the programming process, which only takes a couple hundred millisecond.  The fuses are now restored to their factory default states.  This picture was taken before the voltage doubler, made with the 1N916 and 100 uf capacitor were added.   __ Designed by Dick Cappels

AttoBasic AT90S8515/ATMEGA8515 & ATmega163  -  This interpreter uses on-chip RAM and EEPROM.  Supports power-on EEPROM Execution.  inspired by Nascom Tiny Basic, this byte-wide basic was written to facilitate experimenting with small control systems.   __ Designed by Dick Cappels

AttoBasic Byte-Wide interpreter for ATtiny2313 & AT90S2313 -  A very small Basic interpreter for a very small chip, for limited debugging, monitor and control use.  This interpreter uses on-chip RAM only __ Designed by Dick Cappels

Attobasic with 32k of External SRAM -  This is a continuation of the work on AttoBaisc for the ATMega8515/AT90S8515 __ Designed by Dick Cappels

Audio Activated Recorder -  ScanMate connects between your scanner and tape recorders (via the recorder's microphone or auxiliary input and its remote start jack). __ Designed by Tony van Roon  VA3AVR

Automated USB controlled Power Switch -  Power for TV and set top box (STB) is derived from a common switchboard.  The switched-mode power supply (SMPS) of the TV continues to draw a small amount of power from mains and the STB is not switched off when you switch off the remote.  This next project presents a circuit that can control mains power of an LED TV and the DTH STB.  it also protects the devices from harmful initial surges when power comes back after a power failure.__ Electronics Projects for You

AVR 8 & 20 pin programming adapter  -  Okits not pretty, but its practical.  The 20 pin connector at the far right is left over from a diffferent project and is no longer used.  This adaptor lets me program 8 or 20 pin DiP devices using the in-System Programmer (iSP) described in Atmel's AVR910 application note.  This circuit provides power and clocks for the part to be programmed and power to the iSP circuit.  When programming 8 pin devices, the part is positioned toward pins 1 and 20 of the socket such that the 8 pins of the chip occupy the pins 1, 2, 3, 4, 17, 18, 19, abd 20 of the programming socket.  in the case of an 8 pin part being programmed, the SPST switch that grounds pin 4 must to be closed.  Conversely, when programming a 20 pint part, the switch on pin 4 must be open so the crystal can be used for the clock for the part being programmed.   __ Designed by Dick Cappels

AVR Firmware Monitor Program -  Works on AVR controllers with RAM and a hardware UART.  This code is easily modified to integrate with ROM applications to provide the ability to monitor and interact with ROM applications via an terminal simulation program over an RS-232 port.  it can also be used to stimulate and monitor i/O to aid in debugging hardware.  it is very heLPFul to be able to look around at memory, i/O and peripherals, and change things inside a running controller.  if you adapt this to a controller with a stack pointer that is more than 8 bits wide, be sure that both registers in the stack pointer, both spl and sph, are initialized.   __ Designed by Dick Cappels

AVR Serial Programmer -  Note that the AVR910 programmer does not support all AVR processors, especially the newest chips.  Be sure to check the documentation to see if it supports the version (s) of the processor you are interested in __ Designed by Dick Cappels

Barker Code-Locked Loop Synchronous Demodulator -  A simple, low component count phase locked loop that locks onto and detects the amplitude of an incoming base band 7 bit Barker code using a switched resistor demodulator that is driven directly by a microcontroller's output pins __ Designed by Dick Cappels

Barry's Coilgun Mark I -  These coilguns with control circuits are great!  Now  How can you use them for magnetic levitation?  This is slightly off-topic from coilguns, but magnetic levitation has many common design principles and is a little easier to build.   __ Designed by Barry Hansen

Barry's Coilgun Mark II -  These coilguns with control circuits are great!  Now  How can you use them for magnetic levitation?  This is slightly off-topic from coilguns, but magnetic levitation has many common design principles and is a little easier to build.   __ Designed by Barry Hansen

Barry's Coilgun Mark III -  These coilguns with control circuits are great!  Now  How can you use them for magnetic levitation?  This is slightly off-topic from coilguns, but magnetic levitation has many common design principles and is a little easier to build.   __ Designed by Barry Hansen

Barry's Coilgun Mark IV -  These coilguns with control circuits are great!  Now  How can you use them for magnetic levitation?  This is slightly off-topic from coilguns, but magnetic levitation has many common design principles and is a little easier to build.   __ Designed by Barry Hansen

Bat Detector -  The Simple Bat Detector is a frequency division type device.  Frequency division type detectors allow you to hear ultrasonic sound by digitally scaling the frequency down into the human hearing range.  For instance, a western pipistrelle bat emits ultrasonic sound in the range __ Designed by Tony Messina-Las Vegas, NV

Battery operated FM reBroadcast transmitter  -  This implementation is adapted to rebroadcast the output of a CD player, television receiver, or radio receiver.  I use it so that I can move about the house and listen to my favorite programs without disturbing others.  Within and the house, I find that I can get 10 to 20 meters away __ Designed by Dick Cappels

Battery-powered tube Amps -  A simple battery switch with undervoltage monitor.   __ Contact klausmobile @ yahoo.Com

Beam Robot -  PIC  Project  Most of the BEAM robots I'veseen on the net are using hardware analog electronics.  it seemed that a PIC  would work very well for this kind of project.  Very little extra circuitry is needed to do both forword and backword walking sequences along with a few other tricks.  The PIC 16F818 has a lot of features that work well in this situation.   __ Designed by Luhan Monat - Mesa Arizona

Bedwetting alarm -  A simple two tone water alarm that is light enough to be worn on the upper arm of a sleeper is described.  it uses two LMC555 CMOS timer chips followed by a complimentary pair of emitter followers to drive an 8 ohm speaker.  Power is supplied by a 9 volt transistor radio battery.  An modification to produce a siren rather than two tone operation is discussed __ Designed by Dick Cappels

Bench Supply -  PIC  Project  This unit delivers 0 to 20 volts at up to 4 amps in 0.1volt increments.  The entire device runs on a PIC 16F870 (about $3 in small quantities).  This is basically a switching power supply with the voltage regulation done in software.  The PIC  used here has analog inputs (used to measure voltage and current) and hardware PWM (pulse width modulation) output used to control the power.   __ Designed by Luhan Monat - Mesa Arizona

Better Cheap Video -  PIC  Project  This device uses a PIC 16F1825 for improved performance.  Many of its internal features make it a dandy device for this application.   __ Designed by Luhan Monat - Mesa Arizona

Bike Device -  PIC  Project  For starters, I mounted a 7 amp-hour gel-cell on the frame so that I wouldn't have to keep buying batteries for the headlight.  The headlight is a 12 watt Malibu light from Home Depot complete with a very good diffraction lens.  The horn is a scavenged auto alarm from Walmart.  I just use the horn with.   __ Designed by Luhan Monat - Mesa Arizona

Bob Blick's Propeller Clock -  A motor spins the "propeller", and a small microprocessor keeps track of time and changes the pattern on seven LEDs with exact timing to simulate a 7 by 30 array of LEDs.  it is an illusion, but it works nicely.   __ Designed by Bob Blick

Book PC MP3 Player -  A small computer running Linux with 12 volt power supply and wired remote control makes a great sound system for a car __ Designed by Bob Blick

BookPC Car MP3 Player -  This is an earlier player using a conventional PC motherboard, so the power supply I designed is quite compatible.   __ Designed by Bob Blick

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Electronic Construction Projects: 
#'s - B         C - D         E - G        H - K         L - P         Q - S         T - Z

 


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