We believe that the Hewlett Packard 5082-7010 numerical display was the second generation of the world’s first smart numerical LED display. It’s an exceptionally beautiful chip because the logic die, LED dies, and wire bonds are neatly concealed and plainly visible under a tiny glass cover! These displays are still available on eBay and we've developed this clock for them. The clock uses 7400 and 4000 series digital logic to keep the time. The circuit is the same as our VFD clock timekeeping circuit, but simpler because these displays use the 4 bit binary coded decimal directly from the 74LS90 counters without a 7 segment decoder chip. Requires a USB-C power supply, solder and a soldering iron. 5082-7010 displays are NOT included. There is one eBay seller, Patkor in Poland that has the best deal (and a good stock) of these displays.

The crystal oscillator’s case needs to be glued to the PCB for accurate timekeeping.

The open source design is available here: https://www.boltind.com/open-source-projects/hewlett-packard-5082-7010-numerical-led-clock/