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Timers and Counters Circuits

Timers & Counters:  #'s - A      B - D      E - L      M - S      T - Z

 

Last Updated: October 24, 2017 02:55 PM

Circuits Designed by Dave Johnson, P.E. :
Front Desk Service Beeper -  This device functions like a lobby desk service request bell.  A short beep is sounded whenever the large pushbutton on top of the device is pressed.  Once pressed, the device will not make another beep until at least 2 minutes of time has elapsed . . . Hobby Circuit designed by David A. Johnson P.E.-September, 2005

Garage Door Timer -  The circuit below is designed to automatically close a garage door, if it was left open for a long period of time.  A reed relay and magnet combination sense when the door is fully open.  An ultra low power voltage comparator oscillator and two 74HC4040 ICs are used to generate the time delay. . . Circuit by Dave Johnson P.E.-May, 2011

Laser Used as Vehicular Traffic Counter -  This is an illustration how a laser could be used to count traffic and measure the speed of each car passing through the sensor area. . . Circuit by David A. Johnson P.E.-January, 2007

Line Powered 60hz Clock Generator -  This circuit is connected to the 120vac power line and transfers 60Hz clock pulses to a logic circuit.  The optoisolator used provides 5000 volts of isolation between the power line and the logic side of the circuit. . . Circuit by Dave Johnson P.E.-February, 1999

Long Period Computer Watch Dog Timer -  This circuit uses a simple 4060 IC oscillator/timer that is reset periodically by a computer.  Should the computer fail to send a pulse, the output changes state.  The time can easily be set from seconds to hours. . . Circuit by David Johnson P.E.-January, 1998

Low Power Oscillators -  This page has two unusual two-transistor oscillators.  I set the component values for a low frequency application.  Both circuits draw only about 1 micro amp of current. . . Circuit by David A. Johnson P.E.-December, 2002

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Earthquake Detector -  Here is an ultra sensitive earthquake detector circuit that can sense seismic vibrations.  it can be used to detect vibrations in the Earth.  So it is an ideal device to monitor entry passages.  The circuit exploits the direct piezo electric property of the piezo element used in buzzers.  The Lead Zirconate crystals present in the __ Designed by D Mohankumar

Edge Detector runs off of single supply -  12/04/97 EDN Design Ideas:  You can use a single-supply circuit to generate a pulse on both the rising and the falling edges of a signal for use with counters or similar devices that require only a rising edge to trigger (Figure 1a).  R1 and C1  form a differentiator that converts rising edges to positive spikes and falling __ Circuit Design by Joe Meloche, Ingersoll-Rand Fluid Products Division, Bryan, OH

Egg Timer -  This circuit sounds a buzzer after a preset time with P1 using a common 555 timer IC .  Excellent to cook your eggs perfectly.  Have fun building or bread-boarding this circuit and don't hesitate to experiment on it!  __ Designed by Tony van Roon  VA3AVR

Egg timer, PCB layout & assembly information -  No circuit description, schematic only__ CdS Electronic

Egg Timer -  two 555 timers, a buzzer sounds at the end of the time period, one beeps, the other bleeps!  __ Contact P. Townshend - EduTek Ltd

Eight LEDs Random Flasher -  This project uses a 4026 counter and display driver IC to flash eight LEDs in an apparently random manner.  it can be used to create a display of your choice.   __ Designed by John Hewes

Eight-Digit Counter Works with Common Anode or Common Cathode -  07/15/10 EDN Design Ideas:  A classical design for directly driving eight seven-segment LED displays requires as many as 15 i/O lines.  Previous Design ideas - have described many approaches for using a maximum number of LEDs with a minimum number of i/O lines (references 1 through 5).  The following idea reuses one of these approaches to drive a maximum number of seven-segment LED displays, and it may be useful in designing a lowcomponent- count, low-power.    __ Circuit Design by Charaf Laissoub, Valeo Interior Controls, Créteil France

Electronic Dog Repellent -  The electronic dog repeller circuit produces a discomforting but not harmful, high frequency sound, audible to dogs but not to humans.  Help stop the approach of unwanted dogs at up to 15 feet.  it uses 555 circuit at is easy to build, this is a dog chaser schematic that you can do it yourself.  From R3 adjust the resonance __ Designed by Popescu Marian

Electronic Mail Box -  This Electronic Mail Box circuit generates music intimating the arrival of mail.  The circuit uses a high bright White LED and an LDR to detect the arrival of mail in the box.  IC NE 555 is designed as a Schmitt trigger by shorting its trigger pin 2 and threshold pin 6.  When the light from the LED illuminates the face of LDR, it __ Designed by D Mohankumar

Electronic Metronome with 555 -  This metronome circuit is not modern but is cheap and reliable.  The well known 555 is connected as an astable multivibratos in this electronic metronome and produces a regular train of impulses which can be heard with a speaker.  The metronome frequency can be adjusted with P1.  The power supply is a 9V battery and if you use a __ Designed by Popescu Marian

Electronic Mice Repellent -  This electronic mice repellent emit high frequency sound waves to create an acoustically hostile environment that effectively repels rodents from protected areas.  Sound is inaudible to people and non-rodent pets.  it is ideal for environments were the use of poisons is inadvisable or prohibited.  it is known that a mice can hear __ Designed by Popescu Marian

Electronic Muscle Stimulation -  This is an electronic muscle stimulator circuit that stimulates nerves of that part of your body where electrodes are attached.  it is useful to relieve headache and muscle pain and revive frozen muscles that impair movement.  it’s mainly muscle stimulation aid is removing cellulitis and build up you muscles.  Can be used __ Designed by Popescu Marian

Electronic Scoring Game -  You can play this game alone or with your friends.  The circuit comprises a timer IC , two decade counters and a display driver along with a 7-segment display. The game is simple....__ Electronics Projects for You

Electronic Watch Dog -  Here’s an electronic watch dog for your house that sounds to inform you that somebody is at the gate.  The circuit comprises a transmitter unit and a receiver unit, which are...__ Electronics Projects for You

Emulate Mechanical Metronome -  08/19/99 EDN Design Ideas:  The circuit in Figure 1 produces timing signals with a sound like that of a mechanical metronome.  IC 1 is a 555 timer that oscillates at approximately 3200 Hz.  The two 3-kW resistors and the 0.047-µF capacitor set the frequency.  IC 2 divideas the frequency of IC 1 's output by 2.  IC 2 produces a square wave with an exact 50% duty cycle.    __ Circuit Design by Jim Kocsis

Equivalent & SPICE Model of 555 timer -  Timing and oscillator circuit diagrams / circuit schematics__ 

Exclusive 2.5 GHz Frequency Counter with Blue 2x16 LCD display -  This project explain a very powerful frequency counter which has many useful software functions.  The software can add or subtract 3 different iF frequencies (±455 kHz , ±10.7 MHz and ±21.4 MHz).  You have also two level of resolutions, 1kHz and 100Hz __ Contact maxit91 @ hotmail.com

Exclusive 2.5 GHz Frequency Counter with Blue 2x16 LCD display -  This project explain a very powerful frequency counter which has many useful software functions. 
The software can add or subtract 3 different iF frequencies (±455 kHz , ±10.7 MHz and ±21.4 MHz).  You have also two level of resolutions, 1kHz and 100Hz.  The main oscillator can be on-board 13MHz or external 10 MHz.  The counter data can easy be transmitted to computer with RS232 cable (software below) The construction is extremely simple and the unit is very small.  This project comes in a KiT version, se more details below.  __ 

Experimental DDS frequency synthesizer uses the AD9851 -  This DDS generator uses the AD9851, which is like an AD9850 but includes an internal 6x reference clock multiplier.  I use it with a 10.000MHz OCXO, type HCD71. __ Designed by Hans Summers

Exponential Voltage-to-Frequency Converter for Music Synthesizers -  Logarithmic characteristic of BJT is used to provide an exponential control effect on V/F function.  By using a multiple transistor array, a thermal stabilization circuit assures a constant operating point for the log function.  __ Linear Technology/Analog Devices App Note, Jun 21, 2011

Exposure countdown timer based on an Atmel ATtiny2313 -  This is a countdown counter based on ATtiny2313, primary developed for my PCB exposure box, but it can be used for other purposes too.  The counting range is between 1 and 90 minutes and it can be adjusted with up or down buttons (high and low in the pictures).  After the desired time is set, the countdown starts by pressing the start/stop button (on/off in the pictures).  By pressing the same button we can interrupt the counting at any time we want.  __ AVR Projects Dim

Extend the timing capabilities of a PC -  10-Jan-02 EDN Design Ideas:  Even when you use the internal timing registers and under DOS, a PC cannot easily measure time intervals with better time resolution than a millisecond.  Measuring long intervals with even this precision is a waste of many CPU cycles.  A microcontroller is well-suited for this task; you can easily integrate a PIC  with a PC to extend the timing precision into the microsecond range for perio __ Circuit Design by Martin Connors, Athabasca University, Athabasca, AB, Canada

Extended Period 555 On-Pulse Timer -  Long and longer timeout periods are frequent goals for the ubiquitous 555 timer.  Generally, this is accomplished (albeit unreliably) by unusually large electrolytic timing capacitors.  However, here the long period is accomplished by a more predictable ceramic or film capacitor and substantially reduced charging current.  The __ Designed by Jim Keith

F84 Miniature Real-Time Controller -  Build a simple real-time controller with PIC 16F84 running at low power X-tal 32, 768Hz.  Daily scheduler for 6-channel resided in 64-byte EEPROM can easily be pre-programmed using Nigel PicProg __ Designed by Wichit Sirichote

Failed Power Light -  This back-up lamp stays off as long as light falls on the CdS photocell from either the NE-2 or from room ambient light.  So, if the power fails at night, the lamp will light.  The 6 volt lamp should be directed away from the photocell __  Contact:  Charles Wenzel of Wenzel Associates, Inc.

False Triggering Eliminator for Timer 555 -  Normally, false triggering of timer IC 555 takes place during power on, resulting in unwanted output, which starts the timer’s time cycle.  The circuit becomes inefficient especially when the load has...__ Electronics Projects for You

Fan Timer Based On Motorola 68HC908QT2 -  My son got his fan in the bedroom.  The fan has mechanical timer for 0-180mins.  One day it broken.  So I got the idea to use Nitron chip to replace the mechanical timer.  Someone may ask me why so complicated timer made by microcontroller chip? Actually we can build a timer with 555 and a 14-stage CMOS counter!  The 555 runs astable with time constant controlled by RC and for long period timing we can divide the output frequency of 555 by a CMOS counter.   __ Designed by Wichit Sirichote

Fastest 555 Oscillator -  The highest frequency can be obtained by connecting the output to pins 2 and 6.  This arrangement takes about 5mA and produces an output as shown:__ 555-Timer

Feedback Eliminates CCD-Driver Delay Mismatch -  18-Sep-03 EDN Design Ideas:  in a CCD (charge-coupled device], packets of charges shift across the array.  The transistor array, also called a bucket-brigade shift register, receives drive from a dual-phase clock signal.  Dual-phase clock signals comprise two synchronized clock signals that are 180° out of phase.  High peak-output-current CCD drivers can buffer the logic-level clock signals and turn them into high-voltag __ Circuit Design by Mike Wong, Intersil-Elantec, Milpitas, CA

Fish Feeder -  an interval timer that can pulse a feeder on for 10-22 seconds every 1, 2 or 4 hours __ Contact P. Townshend - EduTek Ltd

Flashing Indicators -  Need to flash "turn indicators" using a 555 and a single 20 amp relay.  Here is our suggestion.  The timing resistor needs to be selected for the appropriate flash-rate.  __ 555-Timer

Flashing LED -  This simple project makes a good low-cost first project to check your soldering skills and learn to identify common components.  The LED flashes at about 3Hz (3 flashes per second).   __ Designed by John Hewes

Flashing Railroad Lights -  This circuit flashes two red LEDs for a model railway crossing.  __ 555-Timer

Flip Flop -  When output pin 3 is HiGH, the 220n charges through the 220k to 6v.  When pin 3 is LOW, the 220n discharges through the 220k to 0v.  Pressing the switch upsets the 3v created by the two 10k voltage dividers, triggering the flip flop inside the 555 and changing the state__ 555-Timer

Four Decade Digital Counter Project -  This project shows how to build a fast speed four decades counter with an amazing digital integrated circuit.  the 4026 CMOS IC .  With this IC you save a lot of time and money building digital counter/divider projects.  in electronics books you will find different pulse counter circuits; most of them using TTL logic (transistor-transistor logic) that need two IC 's for driving a seven segment LED display, which require more troublesome wiring and a lot of time.   __ Designed by braincambre500 @ yahoo.com

Four Digit Counter -  An Easy to build & multifunctional counter with 7-Segment LED Display. (design added05/04)  __ Designed by Jose Pino

French Revolutionary Clock -  December 16, 2015   if you run a search online, you will discover so-called metric or decimal clocks for sale.  But be careful -- these clocks have what looks like a metric face (10 hour markings and numbering) , but use a standard 12-hour mechanism, with 60 seconds per hour and 60 seconds per minute.  Such a clock is not a metric clock at all. __  Gadget Freak-Case #275

Fridge Door Alarm -  This fridge door alarm is using a 3V battery supply should be placed (in a small box) in the fridge near the lamp or close to the opening.  With the door closed the photo resistor R2 presents a high resistance (>200K) thus clamping IC 1 by holding C1 fully charged across R1 and D1.  When a beam of light enters from the opening,  __ Designed by Popescu Marian

Fridge Saver -  This circuit waits 5 minutes before re-applying the power to a refrigerator to prevent it from having to start up under pressure after a brief power outage.  This is highly stressful for the compressor and the thermal cut-out switch built into the compress __ Designed by Andrew R. Morris

Fridge Saver -  This circuit waits 5 minutes before re-applying the power to a refrigerator to prevent it from having to start up under pressure after a brief power outage.    This is highly stressful for the compressor and the thermal cut-out switch built into the compressor.    This device prevents frequent brief power interruptions __ Designed by Andrew R. Morris

Fridge Saver Beats the Heat -  15-Sep-10 -Design News:   Do your kids, spouse, or friends take too much time scanning the contents of your refrigerator? Have your pets figured out how to open the door and keep it open for minutes at a time? You might need the Fridge Saver, a project created by Chris Popp to show how you can monitor a refrigerator--or __  Gadget Freak-Case #171

Front Desk Service Beeper -  This device functions like a lobby desk service request bell.  A short beep is sounded whenever the large pushbutton on top of the device is pressed.  Once pressed, the device will not make another beep until at least 2 minutes of time has elapsed . . . Hobby Circuit designed by David A. Johnson P.E.-September, 2005

Function Generator Sine / Triangle / Square / SaW / Burst Sweep Noise based on PIC16F870 -  PIC  Project  Sine Triangle Square Saw Burst Sweep Noise - runs on a PIC 16F870 __ Designed by Luhan Monat-Mesa Arizona

Fundamentals of Modal Testing -  Application Note__ Aligent

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Timers & Counters:  #'s - A      B - D      E - L      M - S      T - Z

 


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