RPN83P: RPN calculator for TI-83+ TI-84+ inspired by HP-42S

[bxparks]

I want to mention that there is yet another hardware option for running the RPN83P app, the TI-Nspire with the TI-84 Plus Keypad. I learned recently that the first versions of the Nspire accept interchangeable keypads. If you insert a TI-84 Plus Keypad, the ARM processor starts emulating a Z80 processor running at around 15 MHz, and the calculator essentially becomes a TI-84 Plus Silver Edition with 1.5 MB flash.

Would this run RPN83P? I had to find out. I got one from eBay (for like $19 incl shipping), and yes indeed, RPN83P seems to work perfectly fine! See attached photos.

       

In my personal opinion, this is the ugliest calculator that I have ever owned, the baby blue color is terrible. (There seems to be a rev 2 version of this calculator that is dark-blue or black, with a black TI-84 Plus Keypad. Those are slightly more expensive than the blue version.) But in return for its ugliness, I get an LCD screen that is gloriously HUGE and readable, which is great for people with older eyes like me.

There are multiple versions of the TI-Nspire. RPN83P will NOT work on the ones with a bunch of letters after it: Nspire CAS, CX, CX CAS, CX II, CXII CAS. Those don't accept the TI-84 Plus KeyPad. But the first 2 versions of the Nspire (the blue and the black) are really cheap on eBay. Even with emulation, they are at least 2X faster than the similarly priced 83+ model. The combination of (Nspire + 84+Keypad + RPN83P) may be the best value for a scientific RPN calculator available right now.