Frequency counter and crystal tester kit: 1 Hz - 50 MHz

Not always the case, but here’s a video of unpacking and assembly that’s nice and easy. No fiddly SMD soldering. Everything is shown with the rhythm of an electronicist who gets his kicks with good old fashioned through-hole components. This kit is a dual-purpose pocket test equipment, an affordable frequency counter (1 Hz à 50 MHz) and crystal tester. It has five standard 7-segment displays. Look at the measuring range: 1 Hz to 50 MHz. Especially for this price!

LCD panel meters, temperature or event counter modules are readily available in many electronics retail shops at reasonable prices. But try to find a practical, efficient, and value for-money frequency meter module and you will be disappointed. In that case, this article will, no doubt, be welcome. It describes a module based on a RISC (Reduced Instruction Set Computer) microcontroller, which guarantees accurate measurements over a wide frequency range for a reasonable outlay.

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Modern integration techniques make possible the design of a digital frequency meter with a 41/2 -digit LED display not much larger than a matchbox as shown in the photograph. With the (optional) prescaler, it enables trequencies up to about 1 GHz to be measured. Apart trom use as a stand alone instrument, the meter can also be integrated in an existing apparatus.

The frequency meter described here has a maximum input frequency of about 2 MHz, and is ideal for building into function generators and similar instruments, where it gives a far more accurate frequency indication than the traditional frequency dial.

The PC may not transmit characters to the counter while this is busy executing the command string. Any character, in particular US, has the same effect as pressing the BREAK key on the instrument: it halts the execution of the command string, and takes the counter back to its start state (default). This may, of course, be used to break off a measurement on purpose.

This month's instalment explains how the frequency meter can communicate wtth a PC via an RS232 sertal link. Obviously, to be able to wrttc and download user control programs ta the Instrument, you require full descriptians of the vartous functions avatlable. These descriptions are given here, but before we start listing them it must be mentioned that PC control of the counter is optional, and offers you extra functions over and above manual control (described last month). So, do not worry if you do not have a PC - this instalment ia simply not for you.

After the circuit description and the construction guidelines given last month we now turn to the way the multifunction counter is operated via the extensive menu. Basically. the user entry function builds a string of command characters that are sent to measurement subroutines contained in the control program of the tnstrument.

The instrument described in this three-part article is one you can not afford to give a miss since it is very likely the most advanced frequency meter/pulse generator you can build yourself. Sporting microprocessor control, pulse and period measurement, a battery power option, a built-in pulse generator, LCD readout and fully menu-driven operation, the instrument is compact and portable, and a worthy successor to our famous 1985 microprocessor controlled frequency meter, thousands of which are in use all over the world.

This plug-in card for IBM PC-XT/AT and compatibles forms a cost-efficient alternative to a stand-alone frequency meter. Simple to build and program, the card has a TIL input as weil as a prescaler input with high sensitivity that can handle frequencies up to 1 GHz.