Works great. Windows 10 uses the modem driver for it right away. I use it with PuTTY. I'd love to have a case for it. Meanwhile, I'll probably buy a couple more for my co-workers. The RX/TX lights are cool, and I could see them coming in handy.

I love this clock, especially the tenth-second display. But reading it in real time isn't really possible so I video record it and read back in slow motion to time an audio cue. Pretty awkward. Is there a way I could freeze the display with a relay contact closure or equivalent? My application is measuring the performance of an antique clock. It produces a strike on the half hour that I'm using to gauge its accuracy. Do I really need tenth-second resolution for that, you might ask? Well, I'm getting results as good as 3 seconds per week. Pretty gross, I know, but this is 1890 era technology. (Actually, some were way better than this one.) Thanks
Robert Harrington, Vista, CA

Truly underrated MCU.... I have many projects in mind for this chip. Just wish there was a 100 % Arduino support package for all the features. It costs more than an M0+ but better chip for me.

One note, on my unit the spacers holding the raspberry pi zero to the clock board were a bit tall and would sometimes not make good contact. I just shave a bit off of them and no issues now.

This review pertains to V3.1, which is what is being shipped as of the review date. A new version in in the works. I bought the 'quick kit' and used my own 5V power supply, GPS antenna, and case.

OK, the BEST, but not perfect. First, the GOOD stuff. Nick has taken the care and time to get a LOT of details right. The clock does Daylight Saving Time (and this is not a simple matter with a GPS clock). The displayed time is not just synchronized to the NMEA message from the GPS receiver, but actually uses the GPS PPS signal to advance the seconds (I have another maker's GPS clock that doesn't use the PPS signal, so it has an error of a few tenths of a second - not a huge deal, but not right either). And this clock has tenths of a second. Honestly we all know that's totally pointless for practical purposes, but I wanted it anyway (you do too, I know...).

The user interface is simple to use and intuitive. So, setting the time zone, display brightness, colon mode (off, on, or flashing), tenths digit, and a couple other settings is fast and easy.

Here's what I found that I'd improve, were it my product. On the V3.1, the AM/PM and colons flicker annoyingly at a rapid rate ( a few Hz, coincident with the tenths digit count -the flicker goes away if you only use max brightness). Nick is aware of this, because I returned a model so he could see it himself. I was able to fix it on my clock by adding a 33k resistor from the AM/PM LEDs to ground. Nick and I both spent a fair amount of time pondering this issue, and agree it arises from fact that the Maxim LED driver chip is driving different style of LEDs (0.56" 7-segment, 0.3" 7-segment, T1-3/4, and T1). The Maxim chip is being designed out in the next version, as I understand it, so this issue will be moot at some point.

The LEDs are bright. Too bright in a bedroom, for example, and the dimmest setting is still too bright, at least for me. It'd be nice if there were more range available in the dimmed settings.

The connectors stick out the left and right side of the PCB, which means the cords that plug into them are visible. IMO, having them exit toward the back would be better.

The GPS antenna needs to be mounted where it has a clear sky view. If you plan to keep the GPS antenna indoors, you might find (as I did) frequent 'NO GPS' being displayed. I design RF circuits, including embedded GPS for a living, and I think it'd be possible to get better GPS sensitivity, at least based on comparison to GPS that I've used in other devices. GPS is very sensitive to on-board noise, and I think the switching power supply and Maxim LED driver might be pushing some noise into the receiver or antenna bias line, though I have not investigated this in much detail. The good news is that the micro in the clock just needs a UART line that contains some common NMEA message - I patched in a NEO-6M, and it worked fine, so you're not stuck using the GPS implementation on the board.

If the PCB was smaller, particularly in width, it'd allow more case choices. There's about 3/4" inch to the left and right of the display that forces the case to be wider than needed. Similarly, the display in not centered vertically. Not a big deal, but if you like symmetry you need to offset the board and use an otherwise- oversized case.

The AM/PM LEDs are useless, IMO. I removed mine.

So, there's the good and bad, as I see it...

Bottom line: Would I buy another one? Yep - I already did! As I mentioned, there's nothing better in a GPS clock kit.