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

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

Clock/Calendar/Alarm with EEPROM-Based Interpreter & DS Interface -  This is the timekeeping test circuit.  it includes a one-transistor circuit to switch in the 5V power supply when present and drop back to the 3v battery the rest of the time.  That loop of blue wire-wrapping wire is a lariat used to quickly and easily pull the chip out of the socket during development without damage and without having to reach for the removal tool.   __ Designed by Dick Cappels

Clock-Binary -  This clock displays the time in binary using discrete LEDs.  The use of Flowcode [1] makes it very easy to program the PIC  controller in this project.  The circuit is very simple.  must register on this site __ Designed by Published in Elecktor July/Aug, 2010

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

CMOS Gate Implements Reverse Phase Control -  05/21/98 EDN Design Ideas:  (FILE has severa circuits, scroll down) The circuit in Figure 1 implements a "reverse" phase control, using only a single CMOS 4001 quad NOR gate.  The circuit is known as a reverse phase control because, unlike with common TRIAC or SCR controls, conduction begins at the zero crossing of the ac sine wave.  Timing of the turn-off point __ Circuit Design by JC Johnson, Lithonia Lighting, Decatur, GA

CMOS Gate Makes Long-Duration Timers using RC Components -  03/01/12  EDN Design Ideas:  Use a common CMOS gate to make long duration timers using low-value RC components.  The CD4011 CMOS NAND gate has a typical input current of 10 PA at room temperature.  You can charge a capacitor connected to the gate input with currents on the order of hundreds of picoamperes and neglect the influence of the gate-input current on the charging time of the capacitor.  You normally need large-value resistors to limit currents to this low level.  These resistors are not commonly available.  You can instead use a transistor as a current attenuator, despite its more usual amplifying nature.   __ Circuit Design by Raju Baddi, Tata Institute of Fundamental Research, Pune, India

Compute a Histogram In an FPGA with One Clock -  02/03/11  EDN Design Ideas:  Use a histogram to analyze large amounts of data.  Histograms are often useful tools for analyzing digital data.  To get reliable results from a histogram, though, you must collect large amounts of data, often with 100, 000 to 1 million points.  if you need to collect an ADC’s digital outputs for analysis, you can use an FPGA (Figure 1).   __ Circuit Design by Mohit Kumar, Texas Instruments, Bangalore, India

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

Computerised Universal Timer -  This simple and flexible timer is more accurate than the real-time clock of the computer used for the purpose.  it can be used in laboratories, dark rooms, kitchens, and for competitions...__ Electronics Projects for You

Consecutive Test Sequencer -  This circuit highlights the use of LTC6993 Monostable Pulse Generator and LTC6994 Delay Block/Debouncer in a consecutive test sequencer application.  This example is configured to provide a one second duration sequential test pulses after an initial delay.  The initial delay is provided by the LTC6994 and the consecutive one__ Linear Technology/Analog Devices App Note, Oct 26th 2010

Continuity buzzer is frugal with power -  04/15/99  EDN Design Ideas:  (contains several designs, scroll to find this one) The continuity detector in Figure 1 is based on W Dijkstra's "Fleapower circuit detects short circuits" (EDN, July 2, 1998, pg 122).  The buzzer indicator allows you to devote full attention to making the connection without having to observe an LED.  The circuit also consumes less power than Dijkstra's circuit.  Power comes from two AA or AAA cells, which last for a period equal to their shelf life.  Current consumption is less than 2.5 mA when the circuit detects continuity and less than 1.7 mA for an open circuit.  Open-circuit voltage is less than 100 mV, and short-circuit current is less than 1 mA.   __ Circuit Design by Hans Krobath, EEC, Nesconset, NY

Continuity Tester -  This circuit will detect low resistances and high resistances to produce a tone from the speaker.  it will detect up to 200k and the circuit automatically turns off when the probes are not used.  __ 555-Timer

Continuity Tester -  This circuit senses only dead shorts on a populated board.  it will not ring through or damage components.  it shuts off when not in use.  it was first published in Electronics magazine, June 21, 1979, page 145 __ Designed by Andrew R. Morris

Continuity Tester -  Among the essentials for circuit design and prototyping is the continuity tester, a simple device which provides an audible indication when a sufficiently low resistance is applied between its input probes.  This version has a feature which automatically turns off the tester after about two minutes, thereby saving the 9 volt battery from inadvertent discharge.  The tester produces a high-pitch tone when less than 10 ohms is placed between the input probes.  The 10 ohm threshold is a convenient value that indicates hard-wired paths, but excludes indications for circuit paths through most components.  in addition, the amount of current presented to the circuit by this __ Designed by Arthur Harrison

Continuity Tester Fits Into Shirt Pocket -  10-Jan-08 EDN Design Ideas:  A pocket-sized continuity tester responds quickly to shorts or opens and is protected against connection to a live circuit __ Circuit Design by Tom Wason, Phoenixville, PA

Continuity Tester with a Chirping Sound -  Today, there’s a party at your home.  And you are busy detecting faults in the decorative lights hanging over the boundaries of your house.  You want to finish the job before...__ Electronics Projects for You

Continuity Tester-essential for Digital projects -  This is another invaluable piece of test equipment for digital work.  it has been designed by us to cater for a particular application servicing digital projects sent in for repair.   __ Designed by Collin Mitchell

Control a processor's power supply in real time -  31-Mar-05 EDN Design Ideas:  Dynamic control of processor's supply rail minimizes power consumption __ Circuit Design by Yogesh Sharma, Analog Devices, San Jose, CA

Conversion Handles Binary or BCD -  03/01/12  EDN Design Ideas:  Separate binary and BCD up/down counters permit both binary-to-BCD and BCD-to-binary conversion in one circuit.  The subroutine "FASTBCD" (Listing 1) for 8051 µPs quickly converts 16-bit binary to 24-bit BCD data.  The conversion algorithm involves left-shifting bits from the high-order bit of the binary number into the carry bit while left-shifting the carry bits into the low-order bit of a BCD shift register using BCD left-shift operations.   __ Circuit Design by Keith Rubow, Olec Inc, Irvine, CA

Convert Solid-state Relay to Timer -  05/09/96 EDN Design Ideas:  Finding a 480V-ac solid-state timer having zero-crossover switching may prove to be an impossible task.  Most solid-state timers are rated at only 1A and have voltage ratings no higher than 240V ac.  Solid-state relays (SSRs) , in co __ Circuit Design by Henno Normet, Tavares, FL

Convert Thermostat to 12v Timer Switch -  Find out how to modify a battery powered thermostat to be used as a 12 Volt DC timer switch.   __ Designed by REUK-Renewable Energy UK website

Convert your smartphone into a pedometer & tracking Device -  EDN Design Ideas:  10/22/12    When you go hiking or mountain biking, or simply take a long walk around the neighborhood, you might wonder about the distance you covered or specific details, such as speed.  A specialized device for such a task is an expensive idea.  Now, however, the increasing penetration of smartphones in the market with built-in GPS devices makes it possible to configure a mobile phone to log or send the current readings from its sensors to a server for viewing and processing.   This design idea describes a simple approach to log readings from a GPS using the Python scripting language.  An advantage of Python is that an electronics engineer need not delve into the complex realm of C/C++ calls for Symbian/Android architectures to accomplish this simple task.  All that is required is the installation on a phone of the Python interpreter, along with a text file containing the script.    __ Circuit Design by Ali Asgher Mansoor Habiby and Abdus Sami Abdul Qayyum, Sir Syed University, Karachi, Pakistan

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

Count Down Alarm, 3 LED Displays multiplexed & PIC16F84 -  Here I have added two fets for the time-out switch, it is like an electronic relay, just much more reliable it can be used to sound a big horn, or what ever you like. __ Designed by Thomas Scherrer OZ2CPU

Count Objects as They Pass By -  07/15/10 EDN Design Ideas:  Counting objects is easy when the objects have regular motion, but it becomes more difficult when the objects vibrate or you have to manually move them.  To deal with this problem, you need a reliable, error-free system of detecting an object.  in this case, simple circuits with optical interruption switches, IR barriers, or other sensors don’t work because objects may cross a sensor more than once __ Circuit Design by Vladimir Rentyuk, Zaporozhye, Ukraine

Count-down timer -  On this page, I will introduce the Count-down timer with PIC 16F84A.  I am putting a count-down timer by the hardware on Electronic Circuits Application Garage.  The function of the timer is the same as it approximately. (The stop switch is added) Because this unit was made compactly, the wiring of the back becomes quite complicated.   __ Designed by Seiichi Inoue

Countdown timer may never need battery replacement -  06/23/05  EDN Design Ideas:  Processor-based timer draws microamps __ Circuit Design by Mark E Buccini, Texas Instruments, Houston, TX

Countdown timer with Relay -  Timing and oscillator circuit diagrams / circuit schematics__ Carl's Electronics

Counter IC Provides Wait States for 8031/806 -  06/22/95 EDN Design Ideas:  When you connect a slow device to a µC, you insert a number of wait states to extend the read or write cycle.  For the 8031 or 8051 family, however, no input is available for extending the cycle.  So, to extend the cycle, stretch the period of the clock connected to the µC's XTAL1 input.  in Fig 1, IC 3 is an up/down counter configured as a down counter, with the number of wait states preset at inputs A to D.  The preset IC 4 enables the clock connected to the µC's XTAL1 input.   __ Circuit Design by Y S Tam, Canadian Marconi Co, Ottawa, ON, Canada

Counter Provides Divide by 4.5 Function -  05/22/97 EDN Design Ideas:  it's common practice to use a divide-by-N circuit to create a free-running clock based on another clock source.  Designing such a circuit where N is a noninteger is not as difficult as you might think.  Listing 1 gives the synthesizable VHDL code to configure a divide-by-4.5 circuit.  Figure 1 shows the simulation result for a 50-MHz input clock and a 11.11-MHz output.  You can apply the concept given here for any N, where N is 1.5, 2.5, 3.5.  First, consider what divide-by-4.5 is.  it simply means that, for every nine clocks, you need to generate two symmetrical pulses.   __ Circuit Design by Alex Sumarsono, Baynetworks Inc, San Jose, CA

Courtesy Light Delay for Cars -  Simple circuit has an adjustable delay from 7-40s and fades the lights out at the end of the delay period.  And the same circuit suits all cars.__ SiliconChip

Crank Doorbell -  Here is an interesting hobby circuit of a “crank” door bell!  The circuit is built around a timer 555 and a musical piezo-buzzer.  The circuit works off 9 volt battery supply.  One 9volt PP3/6F22 compact battery is enough for powering the whole gadget.  Timer IC (NE555) is wired in monostable mode to produce a time out __ Designed by T.K. Hareendran

Crossover Gate—Break-Before-Make Interval Timer -  The LTC6994 is a programmable delay block with a range of 1μs to 33.6 seconds.  The LTC6994 is part of the TimerBlox family of versatile silicon timing devices.  A single resistor, RSET , programs an internal master oscillator frequency, setting the LTC6994’s time base.  The output (OUT) follows the input (iN) after delaying__ Linear Technology/Analog Devices App Note, Oct 26th 2010

Crosstalk on the Clock Part 2 -  App Note/ 1841 / Nov-04__ Maxim Integrated

Crystal Considerations with Dallas Real-Time Clocks RTCS -  App Note #58__ Maxim Integrated

Crystal switcher using diodes -  Schematic only, no circuit description __ Designed by Guy Roels ON6MU

Cupboard Light -  Here is a simple circuit that can temporarily illuminate your cupboard or other such usually dark places where mains connection is either not possible or not worthwhile.  The circuit is nothing...__ Electronics Projects for You

Cupboard Lights Switch -  This Cupboard lights circuit is an automatic White LED lamp used to illuminate the interior of cupboard to search things.  The lamp automatically turns on when the door of the cupboard opens and stays on for three minutes then turns off.  The circuit uses the popular timer IC NE 555 for the time delay.  Components R1 and C2 gives __ Designed by D Mohankumar

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

 


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