http://youtu.be/mrvyAr6Z4XQ

Hey guys,

Wanted to show you my case mod. After Mathematica was released for the raspberry pi I was deterined to get a portable pocket calculator running with a pi inside. I managed to achive this, and I can't rememeber the exact cost. But for about $80 I made a calculator that destroys every other pocket calculator on the market. I used to own a TI Nspire CAS, so I'm using that as my benchmark for the best pocket calculator. That is a purpose built machine, so its input and large screen is supierior for sure, certianly handles plots better. But the version of Mathematica on the pi is really not watered down much at all. It runs very slow in comparison to the desktop version, but when compared to other pocket calculators it screams. Please let me know if you have any questions. I hope you enjoy. I had a lot of fun making it.

piCaso
Congratulations; this is really cool work. Do you have a page with a build log and more photos, or other documentation in non-video form? Wht inspired you to use this particular calculator for the project? Can you fit the Pi and battery and screen cleanly inside the existing case? Have you considered figuring out how to interface the keyboard using the Pi's GPIO pins? We have a number of similar projects going on here: one of our members just finished a TI-86 replica made with an off-the-shelf dev board, another is combining a Raspberry Pi and a TI-84 Plus, and I'm planning to use an Odroid-W to create a calculator that can emulate everything between the TI-73 and TI-84+CSE.
I think there is enough interest out there to get a good little project going. Make something that anyone can try to build for themselves.

What I want to get going is better keyboard integration and an eink display

I want to get at least some of the keyboard working. problem is that I had to remove the casio's PCB to make room for everything. Don't know if you guys have seen but there is now a raspberry pi model A+, this thing is far better suited to the project as it is smaller. While it would still probably be too big to keep the original pcb I don't see this as too much of an issue as trying to interface with that keyboard matrix is a pain.
What I think would be better is to have a series of small switches under the directional keys as mouse input can be simulated, so you could do away with the wireless keyboard and control the mouse with the d pad, this would still require the use of onscreen keyboards. moving on from that important keys could also be wired up and mapped in software (like what you saw in the video, so the sin button would type out sin etc.)
I know for sure I would be able to put the 6 or so extra switches required to run mouse input without much hassle, but getting the whole thing wired up so that on screen keyboards are no longer necessary is much harder, that would most probably require some kind of custom made matrix.

The eink display, I wouldn't really know where to start with that one. Waiting for the folks in the raspberry pi forums to get back to me.

Also would love to get a usb rechargeable lithium ion battery in there, that shouldn't be too much hassle.

Most of this stuff comes down to time also, which I don't have much of at the moment. When I get round to it I will make an update model with an A+ and be sure to take lots of pics as I go so I can put a detailed build guide together.

As I say would love to get this going as a project that people can contribute to so please ask away or offer up any suggestions.
Hi KermMartian, I wrote that before I saw your post.

No currently no other documentation, as I say when I make the upgraded model I will be sure to put together a detailed build guide, but please don't hold your breath as I am pretty busy at the momemnt.

These were the kinds of calculators I grew up using so I had plenty lying around to play with. Also they are much smaller than TI's so I thought it was more of a challenge.

Everything fits nicely inside the calculator as long as the cover is on. If you see the original and the piCaso side by side you will not tell the difference. The piCaso is slightly heavier.

I am not such a good electronic engineer so I wouldn't know to interface with the original keyboard matrix in a neat way. However from my little experiments with a volt meter you could seemingly solder directly to the key connections and use them as single switches. But as I say existing PCB is gone anyways.

Edit:

Oh wow I can't beleive I have never heard of the ODROID, the W looks like it is even smaller than a Model A+ and it has battery charge circuitry built in. And it has 4GB of ram and its only $30! wow that thing seems too good to be true.
Is this the best pi alternative to your knowledge?

Edit 2:

Unfortunately I see they got strongarmed out the game by broadcom: http://www.theinquirer.net/inquirer/news/2362800/hardkernel-cancels-raspberry-pi-like-odroid-w-after-broadcom-stops-supplying-soc
did you manage to get one before they stopped?
EDIT: the site seems to be entirely written in French, but FWIW: http://www.librecalc.com/en/ . Open-hardware full-custom board based on i.MX233, 64 (now 128) MB of RAM, etc. They have written some code that works like the TI-82's OS.
The Librecalc guys have announced themselves the project on TI-Planet. The second prototype is almost ready: https://twitter.com/LibreCalc

Other third-party calculator works include:
* the ArithMAX E301, based on a STM32 Cortex-M microcontroller, made by Chinese people. They ported Eigenmath to it. Also documented on TI-Planet, only in French - looks like we didn't translate these news items.
* the recent http://www.cemetech.net/forum/viewtopic.php?t=10884 .
piCaso wrote:
Hi KermMartian, I wrote that before I saw your post.
PS - In the future, rather than double-posting, please edit your post if it has been less than 24 hours since you posted. Thanks. Smile

piCaso wrote:
I think there is enough interest out there to get a good little project going. Make something that anyone can try to build for themselves.
Definitely. With the profusion of these projects that I mentioned, I think there's a lot of potential to get more hardware hackers interested in this sort of project. On that note, do you mind if I include information about this in a news article? Would you mind imgur'ing a photo or two of your device?

Quote:
What I want to get going is better keyboard integration and an eink display [...] The eink display, I wouldn't really know where to start with that one. Waiting for the folks in the raspberry pi forums to get back to me.
Why an e-ink displaying specifically, rather than a monochrome or grayscale LCD of some sort?

Quote:
Also would love to get a usb rechargeable lithium ion battery in there, that shouldn't be too much hassle.
Yeah, that's why I picked the ODroid-W. What are you currently using to power it, USB?

Quote:
Everything fits nicely inside the calculator as long as the cover is on. If you see the original and the piCaso side by side you will not tell the difference. The piCaso is slightly heavier.
Nice! I feel like that kind of a build is more seamless and more attractive. Smile

Quote:
I am not such a good electronic engineer so I wouldn't know to interface with the original keyboard matrix in a neat way. However from my little experiments with a volt meter you could seemingly solder directly to the key connections and use them as single switches. But as I say existing PCB is gone anyways.
Ah, that's unfortunate. It is built as a set of rows and columns: you apply a voltage to only one of the columns (or rows), and read the rows (or columns) to determine which keys are pressed. You read the whole keyboard by very quickly scanning through the rows or columns.

Quote:
Oh wow I can't beleive I have never heard of the ODROID, the W looks like it is even smaller than a Model A+ and it has battery charge circuitry built in. And it has 4GB of ram and its only $30! wow that thing seems too good to be true.
Is this the best pi alternative to your knowledge?

Edit 2:

Unfortunately I see they got strongarmed out the game by broadcom: http://www.theinquirer.net/inquirer/news/2362800/hardkernel-cancels-raspberry-pi-like-odroid-w-after-broadcom-stops-supplying-soc
did you manage to get one before they stopped?
I actually just bought one last week, and it arrived today. It seems like a really powerful board, and I'm very much looking forward to using it for my build. I will be maintaining a topic about my project, so keep an eye open for my experiences using the W.
@Lionel Debroux, nice those are some awesome projects.

I have heard of Arithmax, that seems like a very interesting project and as I said before I prefer casio stuff to TI stuff, as I have never been that fussed about graphing things.

I had not heard of the others however.

Obviously I am biased towards my project but I still think from a pure computational standpoint Mathematica is the most powerful tool of the lot by far. However in terms of practical use as a pocket calculator mine is well behind all of the others.

@KermMartian

Sorry about the double post.

Quote:
On that note, do you mind if I include information about this in a news article? Would you mind imgur'ing a photo or two of your device?

No not at all, I will get you some pics soon.

Eink just because it's cool. I really like the look of it and the low power draw is great. I guess it doesn’t have to be eink, I just want something that lower power, and ideally higher res, but that isn't necessary

Quote:

What are you currently using to power it, USB?

Sorry if it wasn't clear enough in the video but I'm using 3 AAA lithium batteries. They have excellent capacity and are very light, but they are expensive, so a rechargeable option would be much better.
The LibreCalc folks are moving ahead: http://www.librecalc.com/en/blog/second-prototype-preview/
  
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