The final RPN programmable calculator HP ever built was the 35s pictured above. While it has its bugs, it has an impressive 32K of RAM to store data and programs and a powerful 6502 equivalent processor at its core. Sadly it has no permanent storage or PC interface.
My 49g+ is the most advanced HP calculator I own and RPL rather than RPN programmable. RPL, or Reverse Polish Lisp, is a full computer language with elements from Lisp and Forth, rather than the simple proto-assembly keystroke programmming model of RPN and AOS calculators. The 49g+ runs on three AAA batteries and offers both an SD card slot and mini-USB connectivity for transferring data to a PC.
This was TI's 1983 successor to the TI-59 and TI-58C calculators, but built for TI by Toshiba. It lacks the magnetic card reader and solid state modules of the 59 but retains the printer connection to the PC-100A/B/C successor, the PC-200. While also much slower than its predecessor (half the speed), it has a correspondingly incredibly long battery life (years!!) on two LR44 button cell batteries. It also displays mnemonics instead of keycodes as on the 59, making programming much easier. Up to 512 program steps or 64 memories are available for programming, compared to the 480 and 60, respectively, on the 58C, or 960 and 100 on the 59. Nonetheless, the simple, 58/58C/59-compatible AOS programming command set is quite satisfying and capable of solving complex problems. It's also nicely expressed on and circumscribed by the calculator keyboard, with the exception of the hidden OP commands. Really the only downside is the slow processor (220 kHz vs. 440 kHz on the 58/59) and the long period of time it takes to learn keystrokes (1.5 seconds per keystroke in the Learn/LRN mode).
This is by far the most powerful AOS keystroke programmable calculator TI ever made. It's such a pleasure to use, between the large, legible two line (data/menu) screen, large form factor and extensive keyboard, long battery life on 4 AAAs, combined cassette/printer/PC 10 pin Dockbus interface, cartridge options, keystroke plus TMS7000 assembly programmability, and excellent documentation. The calculator is easily mistaken for the similar TI-74 due to its full QWERTY keyboard, but each key also corresponds to a function menu or mathematical function (e.g., x^2). The battery life and performance are both quite good (e.g., 100+ hr battery life on four AAAs) due to the powerful 5 MHz TMS70C46/TMS70011 computer on a chip. Available cartridges include 8k additional RAM as well as Mathematics, Statistics, and Chemical Engineering ROMs.
Given the combination of TMS7000 machine code entry and the exposed header, an excellent future project for this calculator would be to interface a sensor such as a DHT11 temperature/humidity module and collect data. In order to drive the DHT11 to collect data, I will need to find a way to drive single data lines on the header for necessary times to induce the serial data output sequence of the DHT11. This will require developing a custom delay function from TMS7000 assembly (e.g., delay for 30 microseconds).
A more urgent TI-95 project, however, is simply finding a way to save data to "simulated" cassette. It appears cassette emulation is quite reasonable based on the successes of the uno2tap and Tapuino projects. In addition, Jeff Birt has previously developed an adapter to connect the Commodore C2N Datasette, which the uno2tap and Tapuino emulate, to the TI-74 and TI-95. At this point, a three wire Arduino Uno tape interface for both my TI-95 and Sharp EL-5500 III looks like the simplest, most promising option. I am definitely not going back to real tape decks.
Birt states on the AtariAge forum here in reply #38 that pin 3 is cassette in (cassette to calculator), pin 6 is cassette out (calculator to cassette), and pin 5 is cassette enable (remote/motor). Three lines - cassette in, cassette out, and ground - should be sufficient for transfer from a PC to the TI-95 via the uno2tap interface. Meanwhile, on the uno2tap, Arduino lines 3 and 4 are read and write, respectively.
Sadly the uno2tap and Tapuino won't work with the TI-95 because TI and Commodore used different tape formats. Fortunately I soon found a solution, because the TI-95 data modulation was quite easy to decode. Jon Guidry already provided a hint here.
Thus, I just recently completed a replacement cassette interface for the TI-95 and probably the TI-74 Basicalc as well. I call it the CIduino7 (after the original TI CI-7 cassette interface). Find the software here. Also check out the promo video below:
Documentation of the tape file format and development of a keystroke compiler to tape files is in progress. I had a big breakthrough figuring out the tape file headers recently (January 4, 2022). The format is similar to the TI-99/4A tape format documented here. Essentially data is presented in duplicate 64 byte blocks with checksums at the end of each.
I have had my TI-84 Plus since the last few years of high school, which I graduated in 2011. I recently (November 2021) purchased a TI Computer-Based Laboratory (CBL) to use with it for real world data acquisition.
Optimized SEIR model simulation
Watch the HP 35s simulation below!
You will probably need to download this file and view it with UTF-8 encoding to see the proper Greek characters.
Watch the HP 49g+ simulation below!
Watch the TI-66 simulation below!
Mastermind for the TI-95! Classic logic game.
This is the classic logic game in which you guess a four-digit number and get feedback regarding the number of correct digits at correct positions (black) or correct digits at incorrect positions (white). You win when you pick the corect number (4 black digits) at which time the TI-95 prints the number of tries it took to guess correctly. Also an excellent CS primer, as the program demonstrates jumps, loops, flags, indirect addressing, subroutines, conditionals, and branches.
Guess a number between 0 and 99. The TI-95 will tell you if the guess is higher (High!) or lower (Low!) than the randomly selected number. Number of tries printed after you guess correctly. Definitely the "Hello World" of game progams.
Coming soon: TI-95 Ricochet and Battleship. Probably "Airwar" (from Vorticon on the AtariAge forum), Nim, Towers of Hanoi, Tic-Tac-Toe, Checkers, Hunt the Wumpus, Concentration, Simon Says, and more after that.
Coming soon.