The NP-25 Nonpariel Physical calculator project, by Chris Chung

Github open source code

Based on the Eric Smith's Nonpareil simulator project.

Available ready built or in kit form from Chris Chung.

This is a neat scientific calculator machine, sporting as many features as you can find on the vintage famous HP-25 calculator series of the 70's, and a few more options thanks to the improved modern hardware used in this project. Besides the HP-25, it has the capability to support more HP Woodstock and Spice series calculators.

It is based on a MSP430G2553 micro-controller to emulate the real original HP-25 series calculators by running a customized firmware developed by Chris, based on the smart simulation code developed by Eric Smith which in fact run the original calculator microcode.

 

Some of the Kit builders pictures

 

Iceman from MoHPC:

 

 

My onwn build

 

Passive components installed in the lower side of the PCB.
On the original project, it are mounted in upper side.

By moving the passive components to the lower side, the front is less cluttered.