2542AB is an Arduino library for the scantily-documented 2542AB 3.5 segment display. I salvaged one from an INNOKIN iTaste MVP 3.0 vaporizer battery. It's a 12 pin device with .1" spacing. The datasheet I managed to find was a jpeg.

#####Diagram

#####Features

• Psuedo-dimming in software, also conveniently eliminates the need to put current limitors on the anodes.
• Uses Timer/Counter1 for refreshing, controlled with simple on() and off() funcitons.
• Decimal point control, settable minimum and maximum displayable number.
• One constructor to assign all of the pins needed. This library is a pin hog, but I had some to spare at the time of writing.