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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. :
Call-for-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 Dave Johnson P.E.-September, 2005

Camera Shutter Time Measurement -  A while back I received an email from someone who needed a simple way to measure the speed of a photographic camera.  I thought about this and suggested the method below.  It relies on an oscilloscope and a cheap photodiode to measure the speed . . . Hobby Circuit designed by Dave Johnson P.E.-August, 2011

Chicken Coop Door Opener with Timer -  I received an email from a guy in Australia who was trying to build a chicken coop system.  He was planning on using a conventional garage door mechanism to open and close the 6 doors to the coop.  The commercial door opener opened and closed the doors with a single pushbutton.  He wanted to install a standard 220vac powered timer so he could open the doors in the morning and close them at night. . . Circuit by Dave Johnson P.E.-March, 2013

Circuit Forms Divide By 1.5 Counter -  Two inexpensive ICs divide a TTL clock signal by 1.5.  By following the circuit with another flip/flop, you could also generate a divide by three function. . . Circuit by Dave Johnson P.E.-July, 2000

Closet Light with Automatic 3-Minute Timeout -  The circuit below is powered by three 1.5v alkaline AA cells.  With a finger tap to the pushbutton trigger switch, a cluster of 6 wide angle white LEDs is turned on.  The lights remain on for about 3 minutes, then will turn off.  The circuit’s standby current is only a few microamps.  A set of fresh batteries should last at least 200 light applications.  The circuit uses a Schmitt trigger inverter and two transistors.  When the pushbutton switch S1 is pressed, the 10uF capacitor C1 is discharged. . . Circuit by David A. Johnson P.E.-November, 2010

Computer, Long Period, 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 . . . Hobby Circuit designed by Dave Johnson P.E.-January, 1998

Count Cars with Laser -  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 . . . Hobby Circuit designed by David A. Johnson P.E.-January, 2007

Darkroom Camera Shutter Timer -  This circuit was designed to control a film exposure shutter for a darkroom.  It has 8 time steps ranging from 0.35 seconds to 4 seconds.  It is activated by a foot switch and draws power from an external 12-volt DC supply. . . Circuit by David Johnson P.E.-June, 2000

Digital Counter using Pedometer -  There are many occasions when you may want to count something electronically.  Perhaps it is car traffic on a street or items moving down an assembly line.  It might be the number of times a machine is activated or maybe you want to count the number of . . . Hobby Circuit designed by David Johnson P.E.-August, 2008

Divide a TTL Clock Signal by 1.5 -  Two inexpensive ICs divide a TTL clock signal by 1.5.  By following the circuit with another flip/flop, you could also generate a divide by three function . . . Hobby Circuit designed by David Johnson P.E.-July, 2000

Divide By 1.5 Counter -  Two inexpensive ICs divide a TTL clock signal by 1.5.  By following the circuit with another flip/flop, you could also generate a divide by three function. . . Circuit by David Johnson P.E.-July, 2000

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Dark Detector -  When the level of light on the photo-cell decreases, the 555 is activated.  Photo-cells (Photo-resistors) have a wide range of specifications.  Some cells go down to 100R in full sunlight while others only go down to 1k.  Some have a HiGH resistance of between 1M and others are 10M in total darkness.  For this circuit, the LOW resistance (the resistance in sunlight) is the critical value__ 555-Timer

Dark Detector -  Dark Detector with NE555__ 

Dark Room Timer -  This is a circuit for darkroom timer that can produce musical tones after an interval of one second.  __ Electronics Projects for You

Darkroom Camera Shutter Timer -  This circuit was designed to control a film exposure shutter for a darkroom.  it has 8 time steps ranging from 0.35 seconds to 4 seconds.  it is activated by a foot switch and draws power from an external 12-volt DC supply. . . Circuit by David Johnson P.E.-June, 2000

Darkroom timer using PIC16F84A -  Yet another darkroom timer using a PIC  16F84A 4 mhz.  I tried to design a timer that would do everything it needed to do but with the smallest number of pieces and simplest mode of operation.  it only needs the PIC , a four digit LED display, one other IC , a resistor network, one pushbutton switch and a capacitor.  it can run on batteries if you use a solid state relay to turn the exposure light on and off thereby adding a minimum of parts to make a fully functional darkroom timer.  A simple regulator would add only a few extra parts and allow the use of a "wall-wart" for power __ Designed by Lloyd Gordon

Darkroom Timer v2.0A for PCB Exposure Box -  This is an improved version of the Darkroom Timer originally created by Stan Ockers (1999).  Some extra features were added and the PIC  code was modified accordingly __ Designed by Vassilis Papanikolaou

DC Power Wire also Carries Clock or Data -  03/13/98 EDN Design Ideas:  NOTE:  File contains many circuits, please scroll to find this one.  High-side current-sense amplifier, IC 1, offers a simple method of combining low-speed clocks or other signals with dc power in cables between subsystems __ Circuit Design by Mike Hardwick, Decade Engineering, Turner, OR

DCF-77 PIC LED clock -  DCF77 is the name of a german radio station on 77.5 KHz, which gives official time and date from an atomic clock located in Francfort.  The time and date is coded into a 59 bit length frame, and is sent on the air through an antenna, by a 50 kilowatt power amplifier.   __ Designed by Bruno Gavand

DCF77 PIC16F84A Single-Nixie clock -  Here is the nixie clock !  PIC 16F84A microcontroller, single-digit Nixie, sequential hours, minutes and seconds display DCF-77 atomic clock, with automatic or manual time set-up high voltage power supply for Nixie with only 4 components 24 hours cycle programmable extinction time no MikroC compiler licence needed __ Designed by Bruno Gavand

DDS using AD9835 -  The purpose of this project is to learn about DDS circuit.  The AD9835 combines the Numerical Controlled Oscillator (NCO) , COS Look-Up Table, Frequency and Phase Modulators, and a Digital-to-Analog Converter on a single integrated circuit __ Contact maxit91 @ hotmail.com

DDS/PLL based VFO synthesizer -  Timing and oscillator circuit diagrams / circuit schematics __ Designed by Aleksander Stare

Dead-Accurate 6-Digit GPS-Locked Clock, Pt 1 -  Looking for a digital clock that's always dead accurate? This one derives its time signals from the GPS (Global Positioning Satellite) system, so it never needs setting or adjusting.  it features big, bright 58mm-high digits for the hours and minutes, plus smaller digits to indicate the seconds.__ SiliconChip

Decimal DDS Signal Generator -  Timing and oscillator circuit diagrams / circuit schematics __ Designed by zl1wtt

Dekatron-device used for dividing by 10 during the valve era -  The circuit diagram is almost the same as Mike's.  I added an ON/OFF switch and an additional toggle switch to stop the spin.  The resistors are standard types (according to Mike I should've used higher power ones to ensure adequate voltage rating) ; the capacitors need to have sufficient voltage rating.  I didn't have anything rated 400V so I used two 330nF capacitors in series in two places.   __ Designed by Hans Summers

Delay Line Aids in One-shot Simulations -  EDN Design Ideas:  04/26/01     Many designers use small pulse generators to delay signals, open timing windows, drive sample/hold circuits, and other functions.  Though the hardware implementation of these generators does not pose any problems, the lack of dedicated circuitry sometimes puzzles the Spice simulation of the system.  A common approach to this problem is to implement a time constant involving a resistor, a capacitor, and a comparator.  Unfortunately, each time you need a time constant, you must recalculate the resistor value, the capacitor value, or both.  Despite the fact that inline equations can do this job for you, delay lines can often offer a smarter solution.    __ Circuit Design by Christophe Basso, On Semiconductor, Toulouse, France

Delay line eases Spice Dead-time generation -  03/02/00  EDN Design Ideas:  Generating complementary clock signals in a Spice simulation is an easy task.  However, this task gets much harder if you need to introduce some dead time into the signals.  This difficulty is especially true when you're dealing with a variable-pulse-width- __ Circuit Design by Christophe Basso, On Semiconductor, Toulouse, Cedex, France

Delay line has wide duty-cycle range -  06/27/02 EDN Design Ideas:  Today's digital delay lines can process pulses no shorter than their delay times, and that restriction confines the devices to applications in which the duty cycle remains near 50%.  A limited range of available delays (2 to 100 nsec per tap] further limits their use.  Longer delay is available with one-shot multivibrators of standard digital-logic families, but those devices do not retain duty-c __ Circuit Design by John Guy, Maxim Integrated Products, Sunnyvale, CA

Delay Line implements Clock Doubler -  Timing delays are undesirable in most digital circuits.  However, in some cases, delays can be useful—to deal with a µP-speed-compatibility issue, for example.  The circuit in Figure 1a uses a silicon T/4 delay line and an XOR gate to implement a simple clock doubler.  Using a 5-nsec delay unit, a 50- MHz, 50% duty-cycle square-wave input produces a 100-MHz, 50% duty-cycle output clock.  Using a more precise delay line, the circuit can output a triple clock (Figure 1b).   __ Circuit Design by Y Li, SAE magnetics  HK Ltd, Guang Dong Province, China - 7/18/96

Delay line upgrades vintage scope -  04/18/02 EDN Design Ideas:  Vintage triggered-sweep oscilloscopes find use in many applications.  However, they have no internal delay line, so they can't display the pulse that triggers the sweep.  Moreover, early laboratory scopes contain delay lines having insufficient delay to display such pulses during a uniform portion of the sweep __ Circuit Design by Robert Houtman, Blaine, WA

Delay Simulator Debugs Communications Equipment -  10/27/94 EDN Design Ideas:   Phone calls over satellite circuits experience a Ľ-sec transmission delay in each direction.  The low-cost circuit (around $20]in Fig 1a simulates this delay and provide as hooks for inserting noise, echo, and other __ Circuit Design by Stan Sasaki, Lake Oswego, OR

Delayed Audible Alarm -  in this circuit, three multivibrator-type oscillators and a ripple counter are configured to produce an interesting, alarming sound, using two inexpensive integrated circuits plus a few other components.  Operation is as follows:U1A and U1B and their associated components are configured as multivibrators, each of a selected audio frequency __ Designed by Arthur Harrison

Delayed Automatic Power OFF -  This circuit is build with the 555 IC and will automatically turn off the power after 20 minutes.  You can use the circuit to turn off the porch light after you lock the house or similar other uses.  The 555 timer is operated as a monostable and a momentary push on S1 switch makes the output go high which triggers the TRIAC and __ Designed by Popescu Marian

Delayed One Shot -  This circuit highlights the use of the LTC6994 Delay Block/ Debouncer and LTC6993 Monostable Pulse Generator in a delayed one-shot application.  The LTC6994 is configured to provide a rise time delay of 50ms and the LTC6993 is configured to provide a 10ms one shot.  The LTC6994 is a programmable delay block with a range of 1μs__ Linear Technology/Analog Devices App Note, Oct 26th 2010

Delayed Turn-On Relay -  This circuit is a delayed turn-on relay driver and can produce time delays for up to several minutes with reasonable accuracy.  The 14001 (or 4001) CMOS gate here is configured as a simple digital inverter.  its output is fed to the base of a regular 2N3906 (PNP) transistor, Q1, at the junction.   __ Designed by Tony van Roon  VA3AVR

Design low-duty-cycle timers -  08/22/02 EDN Design Ideas:  Designing astable circuits using the industry-standard 555 timer is a straightforward process when duty cycles are 50% or greater.  However, you must overcome the many pitfalls of low-duty-cycle circuits to arrive at a desired result.  Using only ideal components eases the design, but the components themselves are hard to obtain __ Circuit Design by Phil Rogers, Texas Instruments Inc, Rockwall, TX

Designing & Characterizing TRL Fixture Calibration Standards for Device Modeling 11/20/01  -  App Note  Doc #954__ California Eastern Laboratories

Dice -  Press the push switch to 'throw' the dice: this makes the circuit rapidly cycle through the dice numbers so that an effectively random dice number is displayed by the LEDs when the push switch is released.   __ Designed by John Hewes

Digital Clock -  On this page, I will introduce the PIC  controled circuit which is the heart of Ultra High Accuracy Digital Clock.  For the details of the clock, refer to "Ultra High Accuracy Digital Clock version 2". 
As for PIC , PIC 16F873 is used in the relation of the input-output port.  Also, to make a circuit compact, CPLD is used for the peripheral.   __ Designed by Seiichi Inoue

Digital clock based on 74 series logic -  With pleasure the lot of friends of digital clocks that use discernible components, will see this circuit.  it's a clock, with 12hour clue, little simpler in the manufacture from the SamClock.  it�s a designing that became from the friend George Kordogiannis in 1990, which was modified and corrected in enough points by my, until it reach in the current form.  Most completed that uses is TTL, apart from the IC 9 until IC 13, that is CMOS , that they have the faculty to drive display Common Cathode __ Designed by Sam Gordon

Digital clock that receives & displays the time from the Rugby MSF radio transmission (PIC16F877) -  A digital clock which receives and displays the time from the MSF radio transmission, broadcast from Anthorn, Cumbria (54°55'N, 3°17'W).   __ Designed by © Chris Johnson

Digital Clock Timer-PIC16F628 -  This clock timer uses a PIC 16F628 microcontroller to display 3 and 1/2 digit time and control an external load.  The clock includes a calendar with leap year and optional daylight savings adjustments.  The timer output can be set from 1 to 59 minutes and manually switched on and off.  The clock also has a correction feature that allows an additional second to be added every so many hours to compensate for a slightly slow running oscillator.  The oscillator uses a common 32.768 KHz watch crystal and the frequency can be adjusted slightly with the 24pF capacitor on the right side of the crystal __ Designed by Bill Bowden

Digital clock using 2 B7971 HUGE NIXIE TUBES, special muxed -  it looks 10 times better in real life, compared to this small and crap gif animation.  I made it just to give the idea about how it display the time 11:28 __ Designed by Thomas Scherrer OZ2CPU

Digital clock using 2 ZM1040 NIXIE TUBES direct driven -  Simple GiF anim of clock in opperation (19:10) the fading has only 6 levels in gif file sorry, The fading is made using 50 levels of PWM so it looks perfect smooth, in real life. __ Designed by Thomas Scherrer OZ2CPU

Digital clock using 4 ZM1040 NIXIE TUBES mux 2x2 with a PIC16 -  if you want to know more about the electronics in this clock see this page: nixie-clock2x3.htm.   or you can Download Schematic the file: 2x2e __ Designed by Thomas Scherrer OZ2CPU

Digital clock using 6 HUGE LED Displays multiplexed & PIC16 -  I found 8 huge LED 7 segments at a local marked.  so I guess I just had to use them for something usefull hihi. __ Designed by Thomas Scherrer OZ2CPU

Digital clock using 6 NIXIE TUBES multiplexed 1x6 & a PIC16 -  Since I was a kid I have loved the glow of Neon Nixie tubes.  in 2002 it was time to construct a homemade clock ! . __ Designed by Thomas Scherrer OZ2CPU

Digital clock using 6 NIXIE TUBES multiplexed 2x3 & a PIC16 -  Staircase box with 6 ZM1172 Nixie tubes, From Right - From Left;  Better view of the wood, with power off, From Right - From Left - Front View;  This Nixie Clock as a kit for sale From Claus Urbach Using proffesional made double sided PCB cards __ Designed by Thomas Scherrer OZ2CPU

Digital clock using 6 small LED Displays & pure TTL logic -  This digital clock was one of the first home designed constructions I ever did, I was in school 5th grade.
Uses 7490 and 7493 counters, 7474 LED display decoder drivers, the timebase is crystal osc.  and dividers it can run for a few month before the gain or loss is too big, to set the correct time two small switches select 100hz or 10khz clock instead of the normal 1Hz __ Designed by Thomas Scherrer OZ2CPU

Digital Clock with Alarm using DS1307 -  DS1307 is a hardware realtime clock, which works on i2C protocol.  Better graphics using the same old fashioned alphanumeric LCD (type HD44780).  icons which shows the status for Alarm ON/OFF state, which gives a nice and cute look to the clock.   __ Designed by Ajay Bhargav, ajay_bhargav @ hotmail.com

Digital Clock with Timer & Solar Panel Regulator -  This is a combination digital clock timer and solar panel charge controller used to maintain a deep cycle battery from a solar panel.  The timer output is used to control a 12 volt load for a 32 minute time interval each day.  Start time is set using 9 dip switches and ends 32 minutes later. __ Designed by Bill Bowden

Digital countdown timer may never need battery replacement -  23-Jun-05 EDN Design Ideas:  Processor-based timer draws microamps __ Circuit Design by Mark E Buccini, Texas Instruments, Houston, TX

Digital Counter -  A counter whose logical output increments in steps on receiving clock pulses is used for a variety of counting and timing applications.  it is at the heart of digital clock circuitry...__ Electronics Projects for You

Digital Counter using Pedometer -  There are many occasions when you may want to count something electronically.  Perhaps it is car traffic on a street or items moving down an assembly line.  it might be the number of times a machine is activated or maybe you want to count the number of . . . Hobby Circuit designed by David Johnson P.E.-August, 2008

Got Designs?
Please eMail
if you want me to link to and/or post your original design.  Thanks.

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

 


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