A Calculator with Free Software and Open Hardware

We’re fond of open source things here. Whether it’s 3D printers, circuit modeling software, or a global network of satellite base stations, the more open it is the more it improves the world around us. [Pierre Parent] and [Ael Gain] have certainly taken these values to heart with their open handheld graphing calculator.

While the duo isn’t giving away the calculators themselves, they are releasing all of the hardware designs so that anyone can build this calculator. It’s based on a imx233 processor because this chip (and most everything else about this calculator) is easy to source and easy to use. That, and there is a lot of documentation on it that is in the public domain. All of the designs, including the circuit board and CAD files for the case, are available to anyone who is curious, or wants to build their own.

The software on the calculator (and the software that was used to design the calculator) is all free software too. The calculator runs Linux (of course) and a free TI simulator environment in the hopes of easing the transition of anyone who grew up using TI’s graphing calculators. The project is still in a prototype phase, but it looks very promising. Even though the calculator can already run Pokemon, maybe one day it will even be able to run Super Smash Bros as well!

57 thoughts on “A Calculator with Free Software and Open Hardware

  1. Linux? That seems extremely wasteful. Who wants a calculator with a battery life measured in hours/days, that needs to boot up?

    Pretty cool initiative anyway, might pave the way for actual TI-84/Casio competition

    1. Linux isnt all that wasteful, the TI Nspire calculators run linux, and I am able to get around ~5-6 months use with around 1-2 hour use every weekday

      If they remove all the unnessesary features, the battery life should be okay with a b/w screen, they also could just add a much bigger battery into it compared to other graphing calculators

    2. I feel the same way. All calculators I have seen are single-tasking devices. There isn’t any need for the overhead Linux introduces through context switches, kernel code, memory management, etc. I would look at old BASIC computer OSs for something to base this off of. But, to be honest, I probably wouldn’t be able to pull this off so who am I to talk.

      1. On the other hand, it’s pretty neat that it can also be used as a bash or python terminal… so maybe not all bad :)

        I wonder if it has the resources to run something like sage math…

        1. I agree.
          All the TI Calculators force you to write your programs in BASIC, which is (in my opinion) a joke. I may be mistaken, but I believe TI has made efforts to downgrade their calculators to be programmed in BASIC.
          If you could put the Numpy/Sympy modules onto this bad boy you’d have something much more powerful, and MUCH more useful, than any TI calculator. They sky’s the limit on this one: ODEs, complex valued matrices (admittance matrices come to mind), USEFUL vector formulas (anyone doing dynamics?)… As an engineering student approaching finalsthe idea of having a calculator that is totally programmable would be a dream come true.

          Hats off on this one gents

        1. I’d love to see e-ink displays used more often everywhere. The visibility, readability, and power consumption are hard to beat. If people could just get over the refresh rate and lower resolution.

          1. Dude, It is not about the people, I would love to use E-Ink anywhere. But please, go and find a supplier with decent margins/quantity. E-Ink is pested with patents and you will only get parts if you order like 100.000 units. So come down from your horse. E-Ink is accepted by everyone, but the products are hard to come by.

          2. Oh yeah, it’s totally that people need to “get over it” and not that the refresh rate is so poor it makes the screen useless for a wide variety of software/uses.

    1. Love to see something break the incredibly profitable stranglehold TI has on primary education calculators (I’m also an HP user from the dawn of history but nobody needs RPN to bust out of the TI mold). Besides, the TI calculators suck. I had to teach HS math with classroom sets of the overly complicated and severely low resolution pieces of ancient hardware. I often thought about the work needed to do an equivalent with a 320×280 minimum screen and an alternate human and mathematics friendly mode.

      Good on ya!

      1. If you were a student do you really think the school/uni would let you use a unknown/untested programmable device on a test? That’s why most exams have one or maybe two WELL KNOWN calculators that they allow and nothing else.

        1. Yes. Schools are clueless. Even standardized exams allow TI-89s and ban TI-92s and the like because they have a qwerty keyboard. If it looks like a calculator, you could take in anything.

    1. That’s actually an awesome idea! But instead of a modern calculator, if someone could retrofit a TI-81 with this board you would have a cheap open source calculator but with the build quality/buttons of a TI calc.

  2. “The software on the calculator (and the software that was used to design the calculator) is all free software too.”

    I’m not sure the ROM images TI produces which the emulators need to work could really be described as “free.” There is a reason they are never distributed with the emulator file.

    1. There is no emulation of the z80 architecture in our program
      We don’t use any Texas Instruments Rom.
      We can read 82p and 83p files, because we have coded our own ti-basic parser.
      All the mathematical functionalities were coded from scratch.
      From now on we’ll call our program a simulator.
      This simulator is free software, we have not used any copyrighted material (Except ti-basic games coming from third parties, only to check that our parser works well).


  3. Blast! Someone beat me too this… I was just laying out a PCB for a horizontal calculator ala CASIO FX-850P with some awesome Cherry MX clicky buttons and a 320×240 touch screen. STM32F4 with 18650 LiPo, was going to have it emulate either a TI-83+ or TI-92+ from a menu.

  4. That’s an awesome project for the sake of making an awesome project. (and yes, that is enough reason to build something)

    I don’t see it as something for practical use though. I don’t see schools allowing an open source calculator because it would be too easy to use it to cheat. You could include anything in that software, including answers to the next test, text copied out of the textbook, etc… We used to have to do a reset on our calculators in front of the teacher before important tests. Even if they implemented a reset feature whose to say the user didn’t alter it to leave some data in somewhere. It probably wouldn’t be that hard to add some sort of wireless communication too allowing students to share answers.

    Outside of school who needs a dedicated calculator? The screen on mine broke years ago. I just kept the manual and now use an emulator on my phone.

    1. There’s no way on earth the schools would ever allow this (even though cheating is just as possible with the TIs). That being said I still like having a dedicated calculator. I have an emulator on my phone, but I still like to haul around my TI-89 because I can type faster and with fewer errors on the physical keypad. Also my muscle memory is setup for playing Tetris with the TI’s button arrangement.

      1. Yah, I can see where buttons would be nice. I use an HP48 emulator. The normal onscreen “keyboard” looks like the original but crammed into the phone screen along with the display. It has another mode where it only shows the more common keys and they get bigger to fill the space. That actually makes it easier IMHO than the real thing for some situations. It’s still missing the tactile feedback of the real thing though.

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