Mikes Optical Timer Counter

“This page is the result of a lot of effort over the past couple years to develop a quality, inexpensive device to test shutters on the classic film cameras that I have been using…” .. Mike

Mikes Optical Timer Counter

Once built, this counter timer/device is easily adapted to a wide variety of applications, simply by construction of a new sensor. Although designed to be used with photo-transistors, this device can also use relays, transistors and many other kinds of electrical switches as a sensor.

Mikes Optical Timer Counter

Other Projects

Model Railroading, 3 Transistor Audio Preamp for a Dynamic Microphone

Configuration and control of this counter/timer is through a RS232 port. Cable configuration for a usual PC compatible would consist of a null modem cable, with a female connector on the timer/counter end of the cable. The correct cable for a PC or usb to serial adapter with a DB-9 interface is listed in the bill of materials.

delabs Page Digital Timers Counters and Clocks 

VK5JST Amateur Radio Ideas with Photos

The new Ham Project Pages are VHF/HF Aerial Analyser, A 600MHz Frequency Counter.  Then there is a an ESR Meter for Electrolytic Capacitors.

VK5JST Amateur Radio Ideas with Photos

With a two tone tester, a dummy load and an oscilloscope, a transmitter can be really put through its paces. Two tone testing consists of applying two clean non-harmonically related sine waves of approximately equal amplitude to the audio input of an SSB transmitter.

Simple Two Tone Oscillator


The sine waves are typically around 600 – 700Hz and 1800 – 2000Hz i.e. about 300Hz from either end of the audio pass band.

A Simple Two Tone Oscillator

This project was published in the September 2004 issue of the Australian magazine “Amateur Radio”.

Other Readworthy Pages

  • Easy PCB’s Made With Kitchen Appliances
  • How to Make a Q Meter
  • Making a High Current 13.8 VOLT Supply For SSB Transceivers
  • VK5MM’s excellent amateur radio homepage
  • Transformer Construction Details
  • Shortform Method of Designing Power Transformers

The photos at VK5JST Homepage are very educative and express the idea better than words. – delabs

Quasar Electronics – Hobby eStore

They specialise in online mail order electronics for industrial, educational and domestic applications. The company’s founder started selling electronic kits back in 1993 .

Quasar Electronics – Hobby eStore

Electronic Kits, Modules, Hobby Projects UK Superstore. A specialist retailer and manufacturer of electronic kits and modules with over 20 years experience.

Quasar Electronics - Hobby eStore

From electronic starter kits and project labs for kids to hi-fi quality valve audio amplifier kits for audiophiles and industrial controller boards for commercial applications

Official distributor stockists for Velleman, Cebek, Smart Electronics and Quasar Electronics. They also have power supplies, inverters, cables, leads, components, connectors,tools, soldering irons, multimeters, function generators and oscilloscopes.

Quasar Electronics Limited
PO Box 6935, BISHOPS STORTFORD, Hertfordshire CM23 4WP
UK – England & Wales

Tom Jennings – World Power Systems

“I make things, mostly technological, but don’t hold me to that, consistency is not a human virtue. Electronics and software, cast iron and plastics, microcontrollers in vintage automobiles, faux historical machinery that could (not) have been; finely crafted, rigorously rugged, reliable, most often.”

Tom Jennings – World Power Systems

The Model 01a (aka M01a) is a 3″ x 5.5″ self-contained controller board designed for embedded applications. It’s based around Microchip Inc’s in-circuit-programmable 14-bit PICs, and contains I/O expansion, a power supply and various goodies that I found useful in five years of using my previous controller board design.

WPS Model 01a Control Engine

WPS Model 01a Control Engine

The M01 board contains enough support hardware to pull off a lot of functionality. Before I get to handling common interface problems here’s a function-by-function description of the hardware. There’s some subtlety to some of the design that’s worth paying attention to.

Index of www.wps.com, by subject

Technical reference data; obsolete, obscure, hard to find, and sometimes just plain old; mostly things made or written by others.

G-switch timer – Vern Knowles

The timer is built using four small inexpensive CMOS integrated circuits. This allows it to run on just 3V from two small AAA batteries. U1 is a 74HC688 8-bit equality comparator. It compares the switch settings to the counter output and will set pin U1-19 low when they match. The actual counter is U2. It is a 74HC4060 14-stage binary ripple counter with built-in oscillator.

The G-switch itself uses a cantilevered metal bar that pivots down as the rocket accelerates upward. The metal bar actuates a small micro-switch that triggers a digital counter to begin the timing sequence. The timer is designed so that it will not start unless the micro-switch has been activated for a duration of at least 0.5 seconds.

G-switch timer - Vern Knowles

G-switch timer – Vern Knowles – The timer was built using a small prototyping circuit board and point-to-point wiring.

U3 is a 74HC74 D-type flip-flop that is used as part of the triggering logic. U3-12 will be low when the counter matches the switch settings. Consequently, on the next oscillator clock edge from U2-9 the flip-flop output at U3-9 will go low. This is the event that activates the 2N4403 transistor that fires the flash bulb.

Thaikits – Electronic Kits for Learning

A group of test engineers in Thailand who worked in an Electronic factory more than 12 years have started a small business to sell electronic projects and electronic kits worldwide in 2007.

CH012 Transistor Curve Tracer adapter XY Oscilloscopes 2 ranges Bias

Thaikits - Electronic Kits for Learning

Some interesting kits are HHO High Frequency PWM DC Motor Speed Controller 30A, CH018 Cycling Timer 1.5 -180 minutes ON-OFF 12VDC/30A Heavy Duty 110V/240VAC, CH024 ICL8038 Function Generator Sine Triagle Square wave 0.5Hz-100kHz.

5/16 Moo 18 ,Bueng Kham Phroi,Lam Luk Ka, Pathum Thani 12150, Thailand

The Art of Electronics – Paul Horowitz Winfield Hill

The Art of Electronics covers the full range of subjects normally treated in electronics books, as well as a rich complement of important but neglected topics.

The Art of Electronics, by Paul Horowitz and Winfield Hill

The book covers many areas of circuit design, from basic DC voltage, current, and resistance, to active filters and oscillators, to digital electronics, including microprocessors and digital bus interfacing. It also includes discussions of such often-neglected areas as high-frequency, high-speed design techniques and low-power applications.

The Art of Electronics - Paul Horowitz Winfield Hill

Learning the Art of Electronics – A Hands-On Lab Course

This introduction to circuit design is unusual in several respects. First, it offers not just explanations, but a full course. Each of the twenty-five sessions begins with a discussion of a particular sort of circuit followed by the chance to try it out and see how it actually behaves.

The Art of Electronics – Paul Horowitz Winfield Hill

The book includes many example circuits. In addition to having examples of good circuits, it also has examples of bad ideas, with discussions of what makes the good designs good and the bad ones bad. It can be described as a cross between a textbook and reference manual, though without the chapter-end questions and exercises which are often found in textbooks.

Paul Horowitz is a Research Professor of Physics and of Electrical Engineering at Harvard University, where in 1974 he originated the Laboratory Electronics course from which emerged The Art of Electronics.

Winfield Hill is by inclination an electronics circuit-design guru. After dropping out of the Chemical Physics graduate program at Harvard University.