When have you ever gotten anything for free that was worth having? Piano tuning is a highly developed skill and "electronic" piano tuning aids are very complicated programs. Why should it be free?
Because I could not find any good free piano tuning software I made an open source tuning program myself. It already does stretch tuning (though not as sophisticated as some of the commercial stuff out there). You're welcome to try it, you can get it here: https://sourceforge.net/projects/ultratune/I'd love to get some feedback, too.
Thank you for making it open source!
How about Mac?
This "IC Piano Tuner" comes with a nominal price of $4.95. It has beat and partials viewing among others, pretty easy to use.https://www.cc-ast.com/icpianotuner.html
should get one of these
This idea is dead in the water.- It uses heat to tune the strings. And the heat can only lower the pitch.- When it's turned off, the piano goes out of tune again. Terrible for the piano.- The video claims .001 cent accuracy. This is simply not possible. There is no such thing as a perfectly tuned piano, so there is no such thing as .001 cent accuracy. It's just hype at best ... or a deception at worst.
OT!