From Lewin Day on Hackaday:
Back in the 1970s, there were a huge variety of esoteric LED displays on the market. One of those was the DIP-packaged TIL311 from Texas Instruments, capable of displaying hexadecimal, from 0-9 and A-F. While these aren’t readily available anymore, the deep red plastic packages had some beauty to them, so [Alex] set about making a modern recreation.
The build consists of a small PCB fitted with 20 LEDs, and a STM8S microcontroller to run the show. This can be used to emulate the original decoder logic on the TIL311, or programmed with other firmware in order to test the display or enable other display functions. Where the project really shines however is in the visual presentation. [Alex] has been experimenting with potting the hardware in translucent red resin to properly emulate the look of the original parts, which goes a long way to getting that cool 70s aesthetic. Attention to detail is top notch, with [Alex] going so far as to carefully select pins that most closely match the square-cut design on the original TIL311 part.