"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.
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.