We like old screen technology, like Nixie tubes, however they’re frequently difficult to work with since they need higher voltages than digital logic. Vacuum florescent screens (VFD) autumn into this category. While not necessarily “old”, they are ending up being far less typical than LCDs. The primary benefit of a VFD is that it really creates light directly; it doesn’t need a backlight. You’ll discover these screens on different players as well as appliances: CD, DVD, VCR, microwaves, stoves, vehicle headunits, as well as others.

[Sprite_tm] had written off some VFDs, however just recently revisited them with renewed interest. He started by testing what kind of voltage would be needed to drive the display. It took 3V for the filament plus 15V to drive the grids. There are VFD controller chips available, however he wished to get this working with what he had on hand. He had experience with older 40xx series logic, which can be powered by much higher voltages than 5V 74xx. His final schematic has three 4094 serial to parallel chips with an ATtiny2313 controller. A 5V power supply is dropped to 3V with diodes to drive the filament while a improve converter brings it as much as 15V for the 4094s that switch the segments. While the code is certain to this display, it would be a fantastic location to begin your own project.

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