Paul made built an I2C driver for a 16-digit alphanumeric “bubble-type” display. He used four 4-digit DL1414 displays connected to a PCF8575 16bit I2C port expander and a 74138 logic IC. He was nice enough to provide the source files for his project.
Via the forum.
It’s a nice-looking display module, but it’s long obsolete and hasn’t been manufactured for years.
There are a bunch on ebay for around $15 each, surplus. But, yes, not something
you’d want to manufacture. My guess is that a modern unit like the HDSP-2532
by Avago (the real HP, along with Agilent) wouldn’t have that old school look.
I know these displays are obsolete, but the nice thing with the tools and services (Thanks Laen!) at our disposal is that you can do a quirky one-off project like this for not a lot of time and money. The resources I devoted to this project were far better spent than what it would have taken me to wire up these displays on a perf-board and the end result is so much more satisfying. I’m going to start sounding like a geezer, but I can only imagine how much more I could have done in college if things like EAGLE, KiCAD, Arduinos, AVRs, batch PCB runs, etc. were available then. You kids don’t know how lucky you are. Now get off my lawn. :-)
So this project was probably only of limited interest, but it’s also a demonstration of I2C and the Bus Pirate. Maybe it will inspire a solution for a different problem someone else is trying solve, even if they never build my board. Who knows…
–zawada