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• On/Off Flip/flop Circuit with Automatic Timeout
  This circuit is ideal when a device needs to be turned on and off with a single pushbutton switch, but also needs to turn itself off after some period of time. With the components shown, the output will stay on for only about 20 seconds. 

• Poor Man’s 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 people entering doorway.  Commercial counting modules do exist but if you want to use something cheaper, you can modify a pedometer to do much the same thing....

• Poor Man's Timer
  Often during testing of certain equipment and components, you would like to keep track of the elapsed time in hours, minutes and seconds. There are some nice commercial digital timers and counters available for just this sort of application.  However, although it may not be as accurate, there is a cheaper way to go.  I’m sure many of you have some old wrist watches or battery powered dial faced alarm clocks collecting dust in some drawer. 

Mains Clock Controller using AT89C2051 2:  12/04/97 EDN-Design Ideas / (added 3/03)  

Make a DAC with a Microcontroller's PWM Timer:  09/05/02  EDN Design Ideas / (added 2/05)    Many embedded-microcontroller applications require generation of analog signals. An integrated or stand-alone DAC fills the role. However, you can often use PWM signals for generating the required analog signals. You can use PWM signals to create both dc and ac analog signals. This Design Idea shows how to use a PWM timer to simultaneously create a sinusoid, a ramp, and a dc voltage..

Making Low frequency measurements with a Frequency Counter:  Agilent Application Note   (app note added 6/06)

Managing Clock Distribution and Optimizing Clock Skew in Networking Applications:  Pericom Semiconductor App Note # 014 (app note added 02/05)

Measuring Temperature using the Watch Dog Timer (WDT):  Microchip Application Note Published 28-Feb-01   (app note added 6/06)

Measuring Temperature with the PIC16F84A Watchdog Timer Application Note:  Microchip Application Note Published 19-Feb-02   (app note added 6/06)

Medical timer warns when pills are due:  05/10/01 EDN-Design Ideas  / (added 2/06)

Memory Systems Multiplexing for High-Performance Workstations:  Pericom Semiconductor Application Brief # 035 (app note added 02/05)

Microcontroller Provides Timer Function:  01/04/01 EDN Design Ideas /  (added 6/06)

Micro-power pulse generator:  (diagram added 05/07)

Micropower Pulse Generator:  (schematic added 8/03)

Mini DDS (Direct Digital Synthesis):  (schematic / circuit added 05/07)

Modulated Constant Off-Time Control Mechanism (AN-9):  Application Note 9 from Microsem  (app note added 6/06)

Monostable Mode Operation (One Shot Pulse):  Circuit Ideas for Designers Application Notes Advanced Linear Devices, Inc.  (app note added 6/06)

More Accurate PC/AT Clock:  Nixie Tube Clock (added 4/02)

Multicarrier WCDMA Feasibility:  AN-807) Analog Devices Application Notes  (app note added 2/06) 

Multiple Pulse Generator:  I used this circuit to ring my doorbell rapidly three times when a car pulled into my driveway.  R2 and C2 set the output frequency. Use a diode and resistor to change the duty cycle, if desired. R1 and C1 set the cycle time which sets the number of pulses. R3 can be deleted if you have other loads on the power supply. The circuit is activated by applying power to it. The first pulse will be longer than the others.  Designed by Andrew R. Morris  (added 09/05)

NE555 Basic Monostable:  (diagram added 05/07)

NE555 Basic Monostable:  (schematic added 8/03)

Negative Voltage Generation using 555 Timer:  (circuit / schematic design added 6/06)

Network Time Protocol AVR Clock:  (circuit / schematic design added 6/06)

Nixie-Tube Clock #2:  This is a my nixie-tube clock built 8 years ago.  (added 10/05)

Off the shelf watchdog serves in a pinch:  01/07)/99 EDN-Design Ideas / (added 11/05) [Note:  File contains multiple circuits scroll to find this circuit]  The performance of the watchdog circuit in Figure 1 may not match that of a dedicated watchdog circuit, but this circuit is helpful when the only watchdog in the lab doesn’t meet your design’s temperature requirement and when you are in a hurry to finish a prototype. The circuit operates on a simple principle. When digital activity occurs on the input, a charge pump comprising C1, D1, D2, and C2 keeps C2 charged. R1 is the discharge resistor for C2. IC1A detects the charge level through....

Old Dog 555 Learns Six New Tricks:  05/11/95 EDN-Design Ideas / (added 3/03)  

One Transistor timer:  (schematic added 8/03)

Oscilloscope Probing of PC133/Rambus Circuits:  Pericom Semiconductor App Note # 021 (app note added 02/05)

Outputting 50%-Duty Pulses using 8-bit Timer:  Toshiba 900H Series Application Note  (app note added 2/06)

Pacer clock saves subroutine calls:  11/10/05  EDN Design Ideas  /  (added 10/06)  Time-delay routine requires no subroutine calls, avoids stack-overflow hazards.

PC Clock Offerings:  Pericom Semiconductor Application Brief # 020 (app note added 02/05)

Pedometer:  Pedometer has a range of 9.950 meters with2-digits. Slip it in pants pocket for walking and jogging (added 02/05)

Periodic Timer:  (schematic added 8/03)

Phototimer Controls Load:  04/18/02 EDN Design Ideas  /  (added 1/05)  In industrial and home applications, the need sometimes exists for a device that, after activation by some physical effect, such as light, temperature, or sound, switches a load on for a predetermined time. The load, such as a lamp, motor, solenoid, or heater, usually derives its power from the ac line. ...

PIC Digital Clock Timer:  (electronic schematic / circuit added 11/05)

PIC Tock Video Clock #2:  (electronic circuit added 7/03)

PIC12C509 Gym Timer:  (circuit / schematic design added 6/06)

PIC16F84 Miniature Real Time Controller:  (circuit / schematic design added 7/06)