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Symbolibre: open RPi Zero-based graphing calculator...

Started by Lionel Debroux, April 04, 2019, 09:59:13 PM

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Lionel Debroux

Over the past few days, the word has started spreading about a ~university project of a team of 25 French students working part-time for several months, which yielded the Symbolibre graphing calculator effort, based on modern, cheap hardware components and
open source / libre software :)
I'm not involved in that project, I'm just relaying news. To date, most information about the Symbolibre remains written in French, AFAICT.

It's based on a $5 RPi Zero module without networking capabilities (not a "W" model), which brings hardware characteristics previously unheard of on a graphing calculator: 1 GHz ARM CPU, 512 MB of RAM + e.g. 8 GB of Flash (well, whatever one puts inside the internal SD card slot). Only the Prime G2 isn't completely dwarfed by this. The screen is 320x240, like all other graphing calculators with ""high-resolution"" screens.
On the software front, unsurprisingly, it's running Linux, and therefore, it enjoys the widest collection of user-space programs, including giac/xcas, a full-blown Python implementation with a full-featured IDE, etc. There's a screenshot taken on a computer, so it looks like there's a computer version of the software.
They used 3D printing for the case and also keyboard buttons, though their pictures don't show the keyboard buttons.

The best aspect, and it's not surprising, is that the Bill of Materials, detailed in at least one of the topics linked below, amounts to around 80€ in the current setup, and can be decreased by using other power circuits... yes, 80€ is just about the (commercial) price tag of a TI-83 Premium CE or a NumWorks calculator, both of which have immensely weaker hardware characteristics.
Technically, the Symbolibre has much more raw power than needed to run the cores of CEmu, the NumWorks simulator, TilEm and TIEmu, though the input (keyboard...) and UI might be less obvious. Firebird should work, but I'm not sure about full speed emulation of a CX, let alone a CX II in the future.

In France, there's (fortunately) no official list of calculators allowed for the main standardized tests, and as long as the SD card slot is not user-accessible during an exam without opening the case (it isn't), such a calculator probably wouldn't run afoul of stupid standardized testing constraints, especially if a blinking LED is added. This requirement of an exam mode with blinking LED was supposed to be enacted last year, after a 3-year notification period, but it wasn't, because unsurprisingly, many pupils still only had working, but older, models without exam mode.

One of the students is an administrator at Planète Casio; two of the TI-Planet admins (critor and Bisam) met the team and saw the calculators for themselves on April 3rd and 4th. The project was publicly showcased at the ~university on April 4th.
The students' plan is to keep developing the project as time permits, of course. And judging by the interest the project is generating, they might receive external contributors, like NumWorks :)

Official site:
Forum topics in other calculator communities: , , .
Member of the TI-Chess Team.
Co-maintainer of GCC4TI (GCC4TI online documentation), TIEmu and TILP.
Co-admin of TI-Planet.


Thank you for sharing this! I hadn't heard about it and it seems really cool!


Sounds like something that could be easily done with cheap parts, good luck to the team!
  • Calculators owned: TI-83+ (dead?), Casio Prizm (also dead???)
  • Consoles, mobile devices and vintage computers owned: A lot
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Lionel Debroux

The entire content at , be it the about summary or the news items, has now been translated to English :)
Member of the TI-Chess Team.
Co-maintainer of GCC4TI (GCC4TI online documentation), TIEmu and TILP.
Co-admin of TI-Planet.

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