Touch screen for graphing calculator

[Owen] got down and dirty by adding a touchscreen to his TI-84 graphing calculator. The dirty part is the z80 assembly code he wrote to use the linkport as a UART (assembly always makes us feel queasy). Once that was working he implemented some commands using an Arduino and then hooked up an Nintendo DS touch screen. Now he’s got this proof of concept video where he draws on the screen, that input is interpreted by the Arduino, commands are sent through the UART, and the calculator program draws on the screen. Adding a touch screen to something is a lot more impressive when you have to go to these lengths to get it working. Nice job!


  1. chris says:

    hmm, im going to have to make this! I just happen to have a TI-84 calculator and a nintendo DS touch screen lying around, with nothing else intended for them. interesting coincidence…

  2. armindilo says:

    assembly is the language of the gods!

  3. Spork says:

    I wonder if you could remove the grey bezel and place the touch screen under that.

    Then of course the next step is fitting all the electronics inside the TI!

  4. Whatnot says:

    I don’t quite understand what the idea is in regards to endresult, what do you do with a touchscreen on a calculator exactly? I don’t mean this dismissive, I’m just curious.

  5. E says:

    This is a site about hacks and you’re afraid of assembly language?

  6. Finger says:

    agreed: assembly is the language of the gods.

  7. Anon says:

    Geez, I’ve got two friends that program in z80 assembly. It’s not too hard.

    HAD, if you guys are afraid of assembly language then you guys should go back to BASIC.

  8. xrazorwirex says:

    Yeah, no shit. The VERY FIRST programming project I ever did was programming a Z80 in assembly.

    It’s like, “welcome to electronics college, here’s a z80 and these are the available instructions; make an alarm clock.”

  9. cantido says:

    >The dirty part is the z80 assembly code

    Assembly.. oh no~~~! What do you guys write your startup code in?

    >(assembly always makes us feel queasy).

    Not all machines use the same magical “assembly”. The Z80 is actually pretty nice to work with in assembly.

  10. Rocks25 says:

    Assembly is epic.
    Machine code is more epic.
    Of course, we all know that REAL hackers use a magnetic needle to write machine code bit by bit directly to a hard drive disk.

  11. JB says:

    Great hack! I learned assembly using the Z80 back in 1983.

  12. chuckt says:

    It is a nice hack but there needs to be a second installment to this article to show us how it will be used to benefit calculations.

  13. e02jr says:

    @ Rocks25
    Real hackers use a butterfly =o)

    And I agree with the rest, assembly is epic, and not as hard as you would think…

  14. Richard says:

    I can’t help but thinking, if a few more young people learned assembly (like us tired old farts had to in college whether we liked it or not) we’d see some better quality code in all kinds of devices…

  15. Tyler says:


  16. supershwa says:


  17. lexi says:

    lol the best part is that owen is in the 10th grade and is quite cute if i do say so

  18. adamastor says:

    how about acessing the menus/options in touch screen? that whould be nice :)
    but you whould have to reverse engineer the whole ti-83 firmware…

  19. tim says:

    I program in 8051 assembly all the time. I prefer using C, but there’s some things you can’t do in C that you need to do in assembly (like messing around with the stack, startup code, interrupt vectors…) Oh and I’m 21, so some of us youngsters know what’s up

  20. nemo says:

    @adamastor-Interrupts can be used to accomplish that on the calc.

  21. Paul Potter says:

    Very impressive.

    I’d done some Z80 programming on a ZX Spectrum.

  22. RBRat3 says:

    Im 20 now and when i was 16 the first language I learned was assembly. Not that hard at all but rather quite fun atleast I thought.

  23. adam says:

    I’m currently in college and just finished a Microprocessor class last year, Our professor made us learn Freescale HC12 Assembly, It sucked! Although i actually got pretty good at it and after that I started my Senior project, i’m programming an ATtiny in C and i actually missed the control i got with Assembly. The hardest part is learning to think like a machine. As fast and powerful as computers get they are still stupid. As far as any future hacks i’ll stick with C unless my project is extremely time dependent.

  24. jeditalian says:

    if some crackhead didn’t steal my ti-84 plus silver edition..

  25. truthbetold says:

    I can confirm this is fake guys. I go to school with owen and am also on the robotics team with him.He could barely program a basic board let alone do something like this.its just timing. hes that terrible of a programmer and even claims hes working on a way to scale down bioshock and games like that for a ti calculator which is complete bs

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