Woodstock Display Upgrade (a sight for sore eyes)

[markhen]

I got my (first) HP-25 in engineering school in the late seventies, and I still have it, and use it. Some years ago, I thought, “wouldn’t it be nice to have a more readable display?”. I gathered some components to attempt this, but it took several years for me to complete the project. I’ll post several pictures of the completed prototype for your viewing pleasure!

There are several really cool features of this project, and a couple of not-so-cool ones – the highlights are:

Cool:
- Much bigger, more readable display
- A couple of display content enhancements (more on this in posts below)
- Upgrade does not modify the base calculator (it can be removed without trace)

Not-so-cool
- The displays ALONE cost over US$100 per calculator (slightly less if 10, 20 or more are bought)
- The processor chip used is impacted by the global chip shortage (aka very hard to get at the moment)
- The power consumption of the display is a little higher than the original display – but since we’re all using modern batteries with higher capacity, this is really not an issue