We live in an era in which all manner of displays are cheap and readily available. A few dollars spent online can net you a two-line alphanumeric LCD, a graphical OLED screen, or all manner of other options. Years ago however, people made do with little monolithic LED devices. [sjm4306] wanted to recreate something similar, and got down to work (Youtube link, embedded below).
The resulting device uses 0603 sized SMD LEDs, soldered onto a tiny PCB. 20 LEDs are used per digit, which can display numbers 0-9 and letters A-F. The LEDs are laid out in a pattern similar to Hewlett-Packard designs from years past. This layout gives the numerals a more pleasant appearance compared to a more-classic 7-segment design. Several tricks are used to make the devices as compact as possible, such as putting vias in the LED pads. This is normally a poor design technique, but it helps save valuable space.
[sjm4306] has developed a breadboard model, and a more advanced version that has a pad on the rear to mount a PIC16F88 microcontroller directly. We look forward to seeing these modules developed further, and can imagine they’d prove useful in a variety of projects.
For reference, check out these Soviet-era 7-segment displays. Video after the break.