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.

I would imagine this could be combined with the broadcast time signal to automate daylight savings as well. In any case my only gripe was the need to run back to the web to get instructions. Even a slip of paper or a mark on the rear containing a link to a PDF manual would be appreciated.

I purchased the assembled clock circuit board without the case as I wanted to install it into a Hammond Translucent Plastic Case ( the largest one fits perfectly ) so I could install power and GPS antenna connectors on the back ( the power and gps antenna connectors are mounted on the sides of the circuit board so their matching plugs exit the sides of the case nick provides ) and not have any screws heads protruding from the front of the case. I purchased black m3x10mm screws to replace the silver screws that come with the case so they would not be noticeable. Since the screw heads are countersunk into the case front and are farther away from the clock display than those surface mounted heads on the case nick provides, they are not as noticeable and for me make the case and display seem cleaner.
Understand, I’m not bashing or disparaging the case nick sells. It’s considerably smaller than the Hammond case, has AM and PM markings on the front and is considerably less expensive than the Hammond case itself not even including all of the associated hardware, plugs and connectors I needed to complete the installation. It just didn’t fit my aesthetic sensibilities.
Because the Hammond case wouldn’t have the AM and PM markings engraved on the case as does the case Nick provides, I decided to replace the Red PM LED with an orange one. I contacted Nick who replied that he would assemble the circuit board but not install the AM & PM LEDs but would include them so I could install whatever LEDs that looked best.
Nick promptly assembled and shipped my clock. After trying a number of different led color combinations and viewing them through the Hammond Red Case so I would know exactly how they would look I chose a Red LED for AM and an orange ( Amber ) LED for PM.
I purchased a back for the case nick sells from nick to use as a drilling guide for the mounting screws for the circuit board and using it drilled the four mounting holes and the two holes for the setting switches into the back of the case. Nick even offered to refund the cost of the back after I used it to drill the holes if I returned it to him undamaged !!.
I then drilled an 8mm hole for the 1.5x5.5mm power socket in the back of the case below the circuit board and soldered a matching right angle power plug cable to the socket since both the power and gps sockets on the circuit board are mounted on the sides.
I drilled a 1/4” hole in the case back for a 4” right angle SMA male to a right angle sma female bulkhead Cable I got on eBay and mounted the bulkhead connector into the case.
I mounted a 4-40 x 1-1/2” threaded standoff/spacer into each of the 4 holes I drilled into the case back. I then plugged in the right angle power plug cable I attached to the matching jack I installed in the case back and the male right angle sma connector on the 4” cable which is attached to the female right angle sma bulkhead connector also mounted to the case back
( because of limited clearance the connectors need to be mounted to the circuit board before it is attached to the standoffs/spacers ).
I then attached the circuit board to the spacers, attached the front of the case to the case body and attached the active gps antenna and the power supply I got from nick to the power jack and female sma jacks I installed on the case back.
The clock started right up and synced the time to the gps satellites within a minute.
The clock looks and works great and Nick was great to work with.

Very useful to find a power module that does not require any extra components. Easy to assemble, but could use a few more photos/instructions especially a side view of the triacs, as I mounted mine a little lower than optimal for best heatsink contact.

Thermal paste and standoffs are recommended.

Beginner friendly, I only had to review resistor identification.

Mounting holes are a bit small for M3 screws, but they fit without problems.