In article , SWbeginner
writes:

I am looking to build a frequency counter, or buy an inxepensive kit.
Any recommendations?
Needs: low cost, few parts count

Recommendations depend on your intended function.

The general-purpose counter from Almost All Digital Electronics is
good, ready-built with LCD for about $40 (give or take depending on
optional backlight or BIG - actually slightly bigger - LCD, temp.
compensated timebase oscillator, etc.). Try examining
www.aade.com. A good Puget Sound area little company.

A "very low parts count" of one would be the CSI 6100 general
purpose counter from Circuit Specialists, Inc., for $129 ready to
use on either 115 or 230 VAC lines. I have one of those very
no-frills units and it works (just got it as a backup on the bench).
I've seen better displays than this one has but I can't fault the
price for a complete unit ready-to-go.

To roll your own counter-timer-etc., the Intersil ICM7216B 28-pin
DIP will count to 10 MHz by itself and drive up to 8 LEDs, has an
on-board timebase oscillator and function switching internal. The
datasheet has several schematics, fairly complete, for making
your own. Add a divide-by-10 or divide-by-100 digital prescaler
and the input frequency range can extend to 100 or 1000 MHz.
The only problem with that is that Intersil is going to OBSOLETE
the critter and is apparently out of production (unless you have a
very large quantity to order, like many thousands).

The Intersil ICM7226B is, or was, a fancier version of 7216, having
a 40-pin DIP. It seems to be all gone except on paper. Some
distributors may still have some 7216s around in stock. I have
datasheets for both and can forward them in e-mail attachments.

Several websites have nice pages on using the Microchip PIC
16F84 or 16F71 (AADE uses the '71) as a complete counter and
display driver for an LCD, extra transistor things for LEDs, using
only 3 ICs total (plus a prescaler to go higher than about 35 MHz
maximum with the PIC). That arrangement is nice because one
can program in "offsets" of the count such as reading a local
oscillator directly, then adding/subtracting the IF to get the antenna
input frequency. The only problem there with rolling your own is
that, while the PIC development software is free, and program
boards are low cost, if you aren't used to Assembler-like language
and coding at the machine level, you have a large learning curve
to climb. That may be worth it since microcontrollers are VERY
versatile, can do amazing things with some creativity, even put
ASCII legends of all kinds on the LCD screen besides the basic
functions of totalizing a count. PICs of many numbers abound at
distributors such as Digikey and Mouser.

To use lots of ICs of the "74" family, two to three per digit plus the
timebase divider, would be the last alternative. The 74LS190 to
74F190 series is still around but the BCD versions are getting
scarce; binary versions (count of 16) are there but the decade ones
are apparently being dropped for new production. 74LS160 to
74F160 in the same boat. There is even a CD4nnn which has a
whole BCD counter, 4-bit latch, 7-segment decoder-driver in a single
DIP that will work up to about 4 MHz, higher with an input prescaler
(I have to search my PDFs for the exact number).

The IC makers have been winnowing their available types over the
last decade, tightening their belts, dropping some things that did
not sell well (despite their usefulness to hobbyists), adding new
things and getting into the SMT area with a rush that started in the
late 1980s. Expect more type dropouts. Adapt, improvise... :-)

Len Anderson
retired (from regular hours) electronic engineer person