This simple little module
measures just 61 x 67mm and is basically a start/stop timer. It's
crystal-controlled to ensure accuracy, features an open-collector NPN output and
sports a 4-digit LED display.
Currently, there are six timer firmware ICs available. You
simply specify which one you want to build. The choices available to you are as
(1) A Simple Photographic Timer (K148T1);
(2) A Stopwatch with Pause function (K148T2);
(3) A 40kHz Auto-Ranging Frequency Meter (K148T3);
(4) A Programmable Down Timer which counts down in
minutes from a maximum of 10,000 minutes (K148T4);
(5) A Programmable Down Timer which counts down in hours
from a maximum of 10,000 hours (K148T5); or
(6) A Programmable Down Timer which counts down in
seconds from a maximum of 10,000 seconds (K148T0).
As supplied, the kit comes with option (6). If you want one of
the other functions, the firmware (in the form of a different microcontroller
IC) must be purchased separately. The documentation supplied with each option
describes how it works.
Please note that, for this design, all source code is copyright
and is not released with the firmware.