[sdiy] Frequency meter (was Re: Anyone in the UK used RS Calibration Services?)

[Mattias Rickardsson]

On 20 March 2014 22:41, Tom Wiltshire <tom at electricdruid.net> wrote:
> I often find myself in need of a high accuracy frequency meter for audio and sample clock frequencies. 0-25KHz for sure, and 0-200KHz would be nice. Presumably there are expensive pieces of test equipment available that do this job, but does anyone know of a cheap/accurate way to do it?

I've often used the free gStrings Tuner app in my Android phone when I
need to tune an oscillator spontaneously outside the lab. I put the
phone next to a pair of headphones connected to the synth, and the app
shows both the frequency in Hz with one decimal, and the note with a
needle like on an ordinary guitar tuner. This often does the job good
enough, and it couldn't be done much easier or cheaper. Perhaps not
the juiciest solution for us hardware nerds, but what the heck... ;-)

/mr