A new project, Own-Mailbox!


After several weeks, we finally decided that we would not
industrialize Librecalc. Thanks to everybody who wanted to buy one, we would have wanted as much as you to make it a reality !

In France a new regulation make Librecalc incompatible with official exams. It should be added that librecalc trigered a limited enthusiasm among teachers. All this added up it became harder and harder to find a way to make a living out of our project.

Though it is a beautifully project, we’ve learnt a lot, and the sources are still available. We would love to see people make things out of our project.





The first 100% confidential Mailbox!
Plug at your home, read and write emails privately from anywhere in the world.
Own-Mailbox is a home-plugged personal email server, with strong privacy protection measures integrated at its core. It provides self-hosted email addresses, or connects with your existing email address. In both cases you can seamlessly send and receive encrypted emails form anywhere in the world, through Own-Mailbox webmail, Smartphone app, or through an external email software (Thunderbird, Outlook, …).

Own-mailbox, is very easy to set-up and use: as easy as a gmail account.

Own-mailbox automatically encrypts your emails with Gnu Privacy Guard, a strong encryption software, the same software as used by Edward Snowden (as in the movie citizenfour).

Own-mailbox allows you to send and receive 100% confidential messages even with people who don’t use email encryption yet. For this purpose we introduce PLM, a new technique consisting in sending to your correspondent, a filtered and temporary HTTPS link, pointing to your private message hosted on your Own-Mailbox.


Final prensentation of our second prototype.

Before going any further we wanted to make a final demonstration of our second prototype, with labels on the keyboard. We also show the possibility of using an arduino powered directly form the battery of our calculator.

We have published the circuit designs corresponding to this prototype in the download page.

Keep connected because we are probably going to make important announcements concerning the future of this project in a few days or weeks.

By the ways it is also the first anniversary of the librecalc project. It as been one year we have worked on it.

birthday(Image CC BY-SA 3.0 Dérivé de cette image par Tauhid16)

Second prototype preview

The second prototype took a little longer that we expected to be finished.
We still need to do screen painting for the keyboard, and some software adjustment, and maybe paint the casing in some nice color!

But we decided to give you now a preview of what we are currently working on:

List of new features available on this prototype:

  • 128 MB of Ram
  • A prettier casing
  • More usable keyboard (still improvements to come, notably on the directional pad of course! :). Some sensitivity problem have already been solved since this video. )
  • Complete autonomy (It is possible to boot the prototype anywhere, without any external cable, computer, or power supply) . By the way boot time to calculation interface is currently under 8 seconds we are still working on optimizations.
  • Software improvements (Menu, Python, Computer Algebra)

Seconde case modeling.


Why FreeCAD ?

We wanted to use free software for the  3D modeling of the case, as well as the rest of the calculator. Blender is certainly the most famous free software for 3D modeling, but does not seem to be that much adapted to CAO. Many features of Blender are not usefull for modeling the case. (animation,light, textures…).

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Third Board – Imx233 BGA Kicad – Linux does not want to stop booting!

We have sent our third motherboard to production, after many hours working on it. It will allow to have 128 MB of RAM and the possibility to plug different screens (the sharp, and a color TFT one). For this board we used a BGA chip, which is really new for us, and make things more complex. In particular, we don’t know how the soldering process is going to work.

This time we had to create a Kicad Library for the IMX233 BGA, because it did not exist yet. Let’s hope that it won’t be a supplementary chance of failling! We have adapted the length of the tracks to the RAM thanks to our kicad branch  ( here ). The whole circuit is a lot smaller: 5cmx5cm.


Once we had received the board we decided to solder it using the usual soldering technique with the frying pan or almost. Indeed, we first placed all the components except the imx233, and then heated the board so that they don’t move anymore, and so that we can place the imx233 more easily and precisely. We have put some flux over the BGA pads, then we placed the imx233 as precisely as possible, then heated again.


Once the board soldered, we tested its behavior, and then, Ô miracle, everything worked well almost directly. Linux boots again and again! :) Nothing should now prevent us from having a second prototype in the following weeks.

It’s possible to make BGA boards with Kicad and a frying pan! :)

After soldering the second Ram chip the board works with 128MB of RAM. However it requires a u-boot configuration ( see https://community.freescale.com/thread/335883 )

We discovered a bug in the electronic circuit. We’ll correct it and then publish Kicad sources.


Some news about the simulator


First of all the use of the term “Emulator” to call our program seems to have triggered some controversy. Let things be clear:

  • 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).

Since last time when we wrote an article on the ti simulator, it has a bunch of new functionalities:

  • Lists, matrices, strings, and complex numbers.
  • Several curves in the same time, and the possibility to adapt the window.
  • More Ti-Basic functionalities are working, more games are working.
  • It is now possible to edit Ti-Basic directly form our simulator.

A quick demonstration :

From now on, on the software part we will focus more on implementing an interface for a CAS engine.

A working arduino on our first calculator prototype !


We wired a potentiometer on an arduino and plugged the arduino on our first calculator prototype, here is a little video :

On our first prototype, the Arduino only works when the calculator is connected to power supply, but on our next calculator prototype, it should work even on battery. However, the first prototype would definitly work with a shorter USB cable! ;)

(Beside, you’ll notice that we had to tinker a mini-usb male/female, but you can find those in shopping malls. We did it because we did not have any on hand. Anyway, we’re not sure about keeping mini-usb ports on next prototype versions.)

So it’s now possible to do real time signal processing thanks to an Arduino.  It should also be possible to program the Arduino directly from the calculator. There are also smaller Arduino, like the Arduino micro.

The software that we use on the Arduino for the video is available here: libercalcYarduino.tar. (We did not use the Java Arduino environment but a simple Makefile.)

The software that we used on the calculator is a very simple one, build with the SDL library. It reads data coming from the Arduino on the serial link. This software should also work on a standard computer. It’s available here: arduinocalc.tar.

Announcement of the second prototype.

We are currently working on a second prototype which will be a lot more ergonomic. The new board will contain a BGA chip and 128 mo of RAM. The work on the board is already well advanced. It was made thanks to the new push& shove functionality of kicad. The design of the prototype will allow to use the whole available surface for the keyboard. We may include a color TFT screen. It would have for effect to reduce the battery life, but would allow us to have a more fitted screen size, and  benefit from colors. We are heavily working on the casing in order to have a more pleasant visual appearance. We also plan to work on a graphical interface for maxima (or another CAS) in order to bring computer algebra to our calculator.


Play Pokemon on our calculator


Here is a little video of us playing a pokemon ROM with the mednafen emulator, on our own calculator.

The display is not perfectly fluid because the driver for the sharp screen stills need some improvements.

We also upgraded the Ti-simulator in order to be able to launch it in full screen and thus have a better rendering.

Assembling our first prototype

We developed the prototype’s case on FreeCAD and printed it with a 3D printer.

Two wiring are required on the main board :

  • Wiring the battery (+ adding an interrupter on the line)
  • Wiring the screen.

We fixed the battery at the bottom of the case with double-sided adhesive tape. We can then easily set the board on its supporting pins, in the case. Now we can close the case and start the calculator !


A free (as in speech) calculator, made with free software, using free software, and released as open hardware