WP 34s
Scientific/engineering firmware repurposing HP business calculators!
This project has created scientific firmware for the HP-20b and HP-30b business calculators.
WP 34S turns either of these calculators into a powerful keystroke programmable scientific device. According to our customers, it's the most powerful and fastest RPN scientific pocket calculator ever built.
WP 34S is alive and stable since 2011. We have succeeded in satisfying the most picky users - read about their experiences on http://www.hpmuseum.org/forum/forum-8.html. Since 2014, WP 34S runs in version 3.3. Our customers confirm its documentation is excellent and comprehensive (see feedback); a full-color printed edition is available from https://www.amazon.com/dp/153366238X since 2018-10-15. Alternatively, you can get a personalized pdf-manual for a ≥ 9 US$ donation here.
We have also produced the WP 31S which is derived from the WP 34S source code. This is an entry-level scientific calculator. Its printed manual is available from https://www.amazon.com/dp/1499231164 .