Many hackers and engineers have come across the HP hexadecimal seven-segment displays, like the 5082-7359 single-digit, for example. All you need to do is provide power and ground and you’ve got an easy way to display four bits of a bus, or just easily control the display from any number of other outputs. These displays were not only useful, they had a very unique look and aesthetic that everyone loved. Unfortunately, they haven’t been made in the better part of 50 years and so as they got bought and used up, supplies dwindled and prices shot through the ceiling. Well, this Breadboard Hexadecimal Display uses the exact same concept of a built-in decoder to display a hexadecimal representation of its inputs.
In this case, instead of including a custom-designed decoder chip inside the LEDs, an extremely inexpensive microcontroller (the Holtek HT66F3185) has been attached to the module and a single pin header is attached for easy breadboarding. There’s no reason these have to be limited to a breadboard, though! They could easily be mounted on PCBs or anywhere you want to display hexadecimal values. A great application, and a very natural one for this type of display, is showing the contents of data and address buses for homebrew computers. You could single-step your machine and see exactly what is being put on the bus!
Combining a cheap microcontroller and a 7-segment display to re-create the self-decoding displays of decades past is an awesome idea and we really hope to see this product do well. Due to the demand for this type of display and the very neat modular packaging used here, hopefully we’ll start to see these popping up in all sorts of neat projects.
