ESP32 Breathes New Life Into 50-Year-Old VFD
Shiura saved a broken 1973 Casio calculator by turning its retro VFD screen into a Wi-Fi-connected clock using an ESP32.
YouTuber shiura has a long history of making unusual and interesting clocks, so when his Casio Mini CM-602 handheld electronic calculator from 1973 kicked the bucket, he knew just what to do: make a clock using its beautiful, retro vacuum fluorescent display (VFD).
The idea was to blend modern and vintage tech together to make a truly unique timepiece that would be perfect for displaying in the home. After removing the VFD from the old calculator and verifying that it was still operational, shiura designed a new circuit to drive it. This circuit makes use of an ESP32 development board and a pair of M54564P transistor array chips. These transistors can handle switching the 25-volt signals required by the VFD.
The hardware was all wired up on perfboard, then installed inside a slick 3D-printed case. When turned on, the clock grabs the current time via NTP using the ESP32’s built-in Wi-Fi radio. The time is then displayed on the VFD, with updates occurring every second.
VFDs are not so easy to find these days, so reproducing this work might be a challenge. However, the same basic approach could be used in repurposing other types of displays. What interesting types of displays would you like to see turned into a clock? Be sure to let us know if you build them!