Please ensure that JavaScript is enabled in your browser to view this page.

The resulting clock design uses a stack of PCBs, built from the bottom up: a base layer is a binary-coded decimal (BCD) clock circuit, which can be driven by period-appropriate 7400- and 4000-series transistor-transistor logic (TTL) parts or a Raspberry Pi Pico; this outputs the time to an adapter board designed to convert from four-bit BCD to a seven-segment layout; the third layer is the actual clock display, which can drive IV-3 or IV-6 VFD tubes — or, optionally, can be swapped out for a PCB using vintage Hewlett Packard bubble LED or modern seven-segment LED displays.

Bolt Industries has launched a crowdfunding campaign for an open source clock kit with a difference: it uses your choice of vintage vacuum florescent display (VFD) or modern LED technology.

"If you've ever gone looking for a nixie or vacuum florescent display clock on the internet, you've probably noticed that the number of pictures of these clocks far outnumbers the number of actual clocks and open source designs that are available," Bolt Industries' Ian Dunn explains. "This clock is designed to change that with an open source design that is compatible with a wide variety of vintage and modern displays."

The resulting clock design uses a stack of PCBs, built from the bottom up: a base layer is a binary-coded decimal (BCD) clock circuit, which can be driven by period-appropriate 7400- and 4000-series transistor-transistor logic (TTL) parts or a Raspberry Pi Pico; this outputs the time to an adapter board designed to convert from four-bit BCD to a seven-segment layout; the third layer is the actual clock display, which can drive IV-3 or IV-6 VFD tubes — or, optionally, can be swapped out for a PCB using vintage Hewlett Packard bubble-LED or modern seven-segment LED displays.

"This is an advanced soldering kit due to the large number of components, but assembly will be thoroughly documented," Dunn promises of the kits. "Also some surface mount soldering is required on the VFD layer. The surface mount components are not incredibly fine pitched, but they are smaller than the average through hole part."

Dunn is funding production of at least 200 kits via Kickstarter, where bundles are available starting at $40 for the base clock and an LED display that shows the four-bit binary coded decimal output and rising to $70 for a full VFD kit without or $90 with tubes. All hardware is expected to ship in November this year.

The design files for every board, meanwhile, have been released on the Bolt Industries website under a non-commercial Creative Commons license.