Nixie and LED Clocks Scott Baker, http://www.smbaker.com/
This repository holds my propeller-based nixie tube and led clock projects. There are two different main files here, ledclock.spin and in12clock.spin.
ledclock.spin is the LED-based clock. In my prototype, I used 1" tall common-cathode displays that I sourced on eBay. Blue displays will just barely work with no current limiting resistors as they have a forward voltage of 3.0V. Red displays in this size typically come in two varieties: a two led per segment version with a forward voltage of 3.6V and a one led per segment version with a forward voltage of 1.8V. The 3.6V version will not work as the logic on this board is 3.3V. The 1.8V version should work with an appropriate dropping resistor, as yet to be determined.
in12clock.spin is the IN-12 Nixie Tube version. It uses IN-12 nixie tubes, sourced from ebay. There is a high voltage supply on-board to power the tubes. You'll also need K155D drivers.
Both clocks may either be powered from a dallas DS1302 RTC or from a GPS module. My preference is to use the GPS, as this allows the clock to be self-setting. There is an onboard footprint where a fastrax UP501 module may be directly wired and mounted. The UP501 is no longer manufactured, so I've been looking at alternatives such as the U-Blox PAM-7Q which is supposed to be pin-compatible with the UP501. I have not tried the PAM-7Q yet.
There's also a header that should allow connection of a EM406 GPS module.
In addition to the clock functionality, there is a footprint for a Dallas 1822 digital thermometer, should one wish to repurpose this is a thermometer board. I have not tried or coded for the thermometer yet.