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Main Features
- Large 57mm 7-segment hour and minute displays
- Easily readable at 20m or more
- Smaller 14.2mm seconds displays
- 12 or 24-hour operation
- Plugpack powered with battery backup
- Automatic display dimming
- AM indicator in 12-hour mode
- Flashing colon between hours and minutes displays
- Easy-to-use Hour and Minute time setting switches
- Easy daylight saving adjustment
- Unique time accuracy adjustment technique requires no equipment
- Suitable for standard and variant pinout large displays
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This latest clock from SILICON CHIP is no ordinary clock. It is
based on a PIC microcontroller to provide a number of unique features including
the ability to adjust for very accurate timekeeping. For high visibility, it
uses super large digits, 57mm high, for the hours and minutes and smaller digits
for the seconds. The large digits use high efficiency LEDs which means they are
bright and much more visible from a distance than any Liquid Crystal Display
(LCD) could ever be.
Nor does this mean they are blinding at night. The circuit
senses the ambient light and so the display brightness is maximum in bright
light but becomes dimmer in darker conditions. So visibility is good in
virtually all light conditions (apart from direct sunlight).
Not only is this clock big but it can also be adjusted for very
good long-term accuracy. All crystal-based clocks exhibit some tendency to run
fast or slow. Some have a trimmer on the crystal and can be adjusted for better
accuracy but they will still drift due to temperature effects over a period of
time.
Our new design uses a PIC microcontroller and since this is
programmed to provide a counter circuit which is actually a clock, we can
incorporate a neat feature in the software to adjust the count for even better
accuracy. Carefully done, it should mean that the clock keeps time within a few
seconds a year – dramatically better than the average watch or crystal
clock.
The adjustment technique requires you to correctly set the
clock and wait a few days to see how accurately it keeps time. Then a special
adjustment mode is selected on the clock and the number of seconds the clock
differs from correct time (calculated over a period of 60 days) is entered
in.
