My apologies - I did not anticipate such strong demand! It sold out within an hour of my post going out on the list. I'm working to get it back in stock in the next couple of days. Regards, -Jeremy On Sun, Jan 26, 2025 at 8:10 AM Neal Pollack <nealix@gmail.com> wrote: > Unfortunately, following the link to Amazon for the zero crossing detector > shows it is not in stock: > Currently unavailable. > We don't know when or if this item will be back in stock. > > Neal > > On Sat, Jan 25, 2025 at 5:21 AM Jeremy Elson via time-nuts < > time-nuts@lists.febo.com> wrote: > >> I've been tinkering on-and-off over the past couple of years with >> measuring >> mains frequency. One problem I found is that inexpensive and homebrew >> timestampers and counters can often only measure positive signals, not >> bipolar signals. There are various messy solutions to this problem that >> have always seemed a little janky or unsafe to me, so I decided to make a >> clean solution and built a small zero-crossing detector. In case other >> people might find it useful, I made it available for sale for $25 ( >> https://www.amazon.com/dp/B0DK2GTKS4). >> >> The board is simple: it takes 5-12VAC input on a barrel connector from an >> AC wall wart. It gives you a 3.3V square wave output on an SMA connector, >> suitable for plugging into a variety of measurement devices. The AC input >> both powers the device and serves as the source of the signal being >> measured. The square wave indicates high or low depending on the polarity >> of the input. The board is small (about 30mm x 55mm) and includes 4 >> mounting holes. >> >> More information, photos, and some graphs showing data I've collected with >> it, are available here: >> https://www.lectrobox.com/projects/zero-crossing-detector/ >> >> -Jeremy >> N3UUO >> _______________________________________________ >> time-nuts mailing list -- time-nuts@lists.febo.com >> To unsubscribe send an email to time-nuts-leave@lists.febo.com >> >