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Digital  / Logic Circuits 
Digital Circuits:   #'s - C       D - G       H - M       N - R       S - T       U - Z

Last Updated on: Thursday, November 30, 2017 04:23 PM

Circuits Designed by Dave Johnson, P.E.

Poor Man's TimerOften 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, . . . Hobby Circuit designed by David Johnson P.E.-August, 2008

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

PIC16F628 Digital Clock Timer -  This clock timer uses a PIC16F628 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

PIC16F84 Alarm Clock -  This is an alarm clock I built.  It was very effective during the sort time I used it, because I programmed it to play a very annoying tune through a speaker.  I actualy started to wake up before the alarm went of, so other people int he house didn't wake up from the anoying pitches it played.  The Jal sourcecode is available on my download page Features * Timekeeping 

PIC16F84 Debugging Terminal -  Build a simple 9600 BAUD 8n1 LCD terminal for debugging and testing the projects having RS232C output __ Designed by M Asim Khan  asimkhan @ sat.net.pk

PIC16F84 LED Chaser -  There are several projects on this page.  Please scroll down to find the LED Chaser.   __ Designed by Jason KE4NYV from Roanoke, Virginia

PIC16F84 Line following Robot -  The JavaBot1 is a small line following robot designed to follow a black line drawn on a dry erase board.  It is designed to follow very tight curves.  The software still has lot's of room for improvement but works well as is.   __ Designed by James Vroman

PIC16f84 Miniature Real Time Controller -  Build a simple real-time controller with PIC16F84 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

PIC16F84 Programmer -  Build a low-cost and very simple serial programmer for a PIC16F84 Microchip Flash Microcontroller.  Below picture is my personal writer for F84 chip, it works very nice with Nigel WPicProg V1.20.   __ Designed by Wichit Sirichote

PIC16F84 RF remote Controller -  With a handful of inexpensive components, a little creativity, and the power of PicBasic, you can build some pretty outstanding robotics creations as Rob Arnold proves with his Ruf-Bot project.   __ Designed by Rob Arnold

PIC16F84 Serial I/O Expander with Picbasic -  This article shows how to use the PIC16F84 microcontroller with PicBasic to design a quick & effective, serially controlled, I/O-Expander.  Using PicBasic makes developing handysingle-chip devices like this extremely simple.   __ Designed by Reynolds Electronics

PIC16F84 Tone Generator -  Schematic Only __ Designed by Chuck Olson, WB9KZY

PIC16F84 Tone Generator 6 Bit -  Schematic Only __ Designed by Chuck Olson, WB9KZY

PIC16F873 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, PIC16F873 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

PIC18f2550 Project Board -  The new PIC18F2550 Project Board was designed as the development platform for student projects.   __ Designed by Wichit Sirichote

PICAXE Application Special: PICAXE 08 Port Expansion -  Test Your Reaction Times With A Digital Reaction Timer.__ SiliconChip

PICAXE Application Special: PICAXE Telephone. -  PICAXE Telephone.__ SiliconChip

PICAXE Colour Recognition SystE - M -  Use a PICAXE micro and a state-of-the-art optoelectronic IC to create this low-cost colour recognition system.__ SiliconChip

PICAXE Goes Wireless -  Get your PICAXE projects talking over the airwaves using the latest high-tech 2.4GHz Xbee modules__ SiliconChip

PICAXE Goes Wireless , Pt 2 -  Networking.  logging data, plus light & temperature sensors__ SiliconChip

PICAXE Humidity Measuring using the HopeRF HH10D -  Recent SILICON CHIP articles on HopeRF 433MHz data transceivers have drawn our attention to other monitoring modules made by this Chinese firm.  Amongst their offerings is a well-priced and calibrated humidity sensor, the HH10D.  This has shown itself capable of extremely simple interfacing to even the humblest PICAXE, although factory calibration values first need reading via an I2C-level PICAXE such as the 18X.__ SiliconChip

PICAXE Infrared Remote Control -  Here's how to add infrared remote control to all your PICAXE-08M projects  (including Rudolph) __ SiliconChip

PICAXE Net Server, Pt.3 -  Over the last couple of months, we described how to built a demo board for the PICAXE Net Server  (PNS) and then configured a home network to make it accessible over the Internet.  This month, we look at building the first of two Internet-enabled demonstration projects.__ SiliconChip

PICAXE Net Server-Pt.1 -  Control your next electronics project from virtually anywhere on the planet using the Internet and a tiny web serverthe PICAXE Net Server!__ SiliconChip

PICAXE Net Server-Pt.2 -  Accessing the PICAXE Net Server via the internet__ SiliconChip

PICAXE Plays Music -  One of the most popular uses of PICAXE chips is in sound orientated projects.  Both the new PICAXE-14M and PICAXE-28X1 support the 08M 'play' and 'tune' commands, which allow the PICAXE chips to play mobile phone ring-tones directly via a piezo sounder.__ SiliconChip

PICAXE Project Development SystE - M -  With the abundance of microprocessor/microcontroller variations available these days it is no small wonder that many of the designs produced by electronic enthusiasts use one type or another of these components.  And most commercial equipment these days has a micro controlling it.  But how do you get from an idea to a working design?__ SiliconChip

PICAXE VSM: the PICAXE Circuit Simulator! -  Ever wondered whether your latest scathingly brilliant PICAXE project idea would actually work? Well, now you can find out before you build it, with the new PICAXE circuit simulator software! Mr PICAXE, Clive Seager, talks us through the latest PICAXE software offering from Revolution Education.__ SiliconChip

Picaxe-Based 433MHz Wireless Thermometer -  You've no doubt heard of Murphy's, Ohm's and Moore's Laws but how about Swan's Law"You can never have too many thermometers"?__ SiliconChip

PIC-based Flexitimer Mk.4 -  Here's a new and enhanced version of a very popular project: an easily-programmed low-cost electronic timer module.  It's compact, easy to build and offers a choice of either a single on period or continuous on/off cycling with independently programmable periods.__ SiliconChip

PIC-Based Musical Tuning Aid -  This compact device will help you tune almost any musical instrumentacoustic or electronic.  It can produce any note on the tempered musical scale    (standard pitch) in any of the eight most commonly used octaves, with an accuracy of better than ?0.08% or 1.3 musical cents.  The selected note is compared with that from the instrument either by ear or visually by using an eight-LED stroboscopic beat indicator.__ SiliconChip

PIC-Based Water Tank Level Meter Pt.2 -  Last month, we published the circuit of the Water Tank Level Meter and described how it worked.  This month, we show you how to build both the basic and telemetry versions and detail the installation.__ SiliconChip

PIC-Controlled Swimming Pool Alarm -  Reduce the possibility of a drowning in your swimming pool.  If someone falls in, an excruciatingly loud siren sounds.__ SiliconChip

PICProbe: a versatile Logic Probe -  A versatile PIC-based logic probe that fits inside a Biro case!__ SiliconChip

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Digital or Logic Circuits:  #'s - C       D - G       H - M       N - R       S - T       U - Z

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