Hey! I think I have some of those. Since I'm never going to use them, I
suppose I could part with them.

But first the obligitory assesment of assumptions: Why are LCD displays not
an option? Could you drive an LCD from your PIC? I've seen info on this
from the LCD manufacturers; it looks quite doable from a PIC.

"Avery Fineman" wrote in message
...
In article , "Dale Parfitt"
writes:

Anyone know of a PIC based frequency counter using the low current 7
segment
readouts as in the Elecraft KX-1? Size, durability and I drain are the
important factors here- LCD displays are not an option.

A problem there is finding an LED numeric display with low current
per segment or a driver capable of higher peak current for sequential
strobing of an array of LEDs. The only thing that I could recommend
is the miniature LED array with integral magnifying lens and filter
that
HP made for their first scientific calculator, the HP-35.

In the HP 1979 Optoelectronic databook, the 5082-7200 series and
5082-7400 series have varying numeric character assemblies from
2 to 16 digits. The 5082-7240 is an 8-digit assembly "capable of
being driven by MOS circuits" (according to catalog text, apparently
in reference to calculator use). Average per segment current is
about 0.5 mA and peak current (for strobing array) is 5.0 mA. The
character height is 2.59mm by 1.52mm wide but magnified by the
integral plastic lens. I've stared at that HP-35 calculator display
long enough without eyestrain from the appearance (only headaches
from results not meeting expectations). Brightness is okay to use
in a well-lighted office environment but gets a bit dim outdoors in the
shade (such as a QRP outing?).

I don't know if they are made any more, couldn't get through the
Agilent-HP site to find them. Someone makes those little LED
numeric arrays now, used in hand-carried frequency counters.

A PIC would strobe segments and the program could be adjusted
to optimize the on-time duty cycle for a particular segment. In using
unmagnified LEDs, the average segment current is around 5 mA
minimum for sufficient brightness but that is variable depending on
the molded-in filtering for various colors (attenuates brightness).
Strobing would require higher peak currents.

Len Anderson
retired (from regular hours) electronic engineer person