July 7th, 2021—
Nixie tubes are a great throwback to an era before the advent of LED and LCD screens; however, they often require expensive components or complex programming to operate. This challenge is what inspired Doug Domke to come up with his own solution that only costs $110. His design incorporates the Arduino MKR WiFi 1010, which has a powerful processor, ample amounts of storage, and WiFi connectivity along with a real-time clock.
In order to keep component costs down, letting each 170-volt Nixie tube have its own binary-to-decimal decoder chip would have required a total of 24 pins on the Arduino which it does not have. So instead, Domke used a few resistors, transistors, and a multiplexer to route the high voltage signals from the MKR WiFi 1010’s GPIO pins to the display. There is, unfortunately, a drawback to this approach, as only a single Nixie tube can be lit up at any one moment. Therefore, the code loops through each tube rapidly and flickers it faster than the human eye can perceive, thus giving the appearance of a solid digit.
After using the network time protocol (NTP) via the RTCZero library to set the time with incredible precision, Domke went about testing his project. As can be seen from his video below, the Nixie tube clock works great within its custom enclosure, and it will be exciting to see what new features will be added in the future. To read more about how this device was created, check out Domke’s write-up here.