Turning a TI-30XB Multiview calculator into a PDA

[nk22]

Hello.

This is my first post, so it is pretty clear that I am a noob at D.I.Y electronics, but I've been searching for them for a pretty long time now.

My idea was, to turn my useless TI-30XB Multiview calculator, into an superawesome mediaplayer thingy, aka a PDA. I was considering to buy a Raspberry Pi B+ for this, but then I discovered that that wouldn't fit in the case of the TI-30XB. So, what microcomputer should I choose now?
Quick Note: It is a mediaplayer, so no 16x4 LCD display's. Another note, I don't own a 3D printer, that's why I want to build it into this calculator.

The TI30XB Multiview, that's the calculator

[adafruit_support_mike]

That project is more of a challenge than I'd wish on a beginner.

Calculators are extremely optimized devices, and TI has long since mastered the art of building them from the smallest possible number of pieces. When you open it up, you'll see a PCB with a lot of traces running to a single blob of epoxy. Under that epoxy is a silicon chip glued directly to the PCB that contains all the calculator's intelligence.. math functions, keyboard input, and possibly the LCD driver. You can't change how the chip works, or even see it without using severely hazardous chemicals.

Go ahead and open it up to see what's inside. If you're lucky the LCD will have its own driver and you'll be able to use that independently of the Chip On Board (COB) calculator.

[nk22]

I 'luckily' had a kind of broken back, so i could see the board of the LCD without using a screwdriver. It does look like the LCD has a separate chip, other than the one from the calculator itself. On the chip, there were several codes: SR21, SR21B (which was marked red), SR21P, SR34 and SR34P. It seems to be that there is an LCD driver, hurray!

[adafruit_support_mike]

Hmm.. this page has photos from the inside of the TI-30XB, and they show a unified calculator/display driver:

http://www.datamath.org/Sci/Modern/JPEG ... VG.htm#PCB

It's a two-PCB design, with what I assume to be a general-purpose calculator board PCB cabled to a device-specific keypad PCB. There's a bit more information about that model here:

http://www.datamath.org/Sci/Modern/TI-30XB-MVG.htm

[nk22]

But can't i just throw everything out, except the buttons and the case, put an Arduino/Raspberry Pi in it, new screen and that's it?

[adafruit_support_mike]

Oh, you're just gutting it to get the enclosure?

In that case you don't have to worry about the electronics inside, but do need to pay attention to the dimensions. I doubt you'd be able to fit a RasPi or regular Arduino into that shell, but you could probably make one of the small dev boards like the Teensy 2.0 work:

https://www.adafruit.com/products/199

That packs a fair bit of computing power into a very small space.

The Teensy 3.1 is even more powerful:

https://www.adafruit.com/product/1625

but uses a completely different microprocessor than the Arduino.

If you're new to working with microcontrollers, I'd suggest getting a plain Arduino Uno:

https://www.adafruit.com/product/50

and working through the tutorials over in the Learning System to get used to the basic tools and techniques:

https://learn.adafruit.com/category/learn-arduino

That will give you a baseline with one of the most widely known and supported platforms. Once you're comfortable there, you'll only need to learn a few details to get used to the Teensy 2.0. From there you can move to the Teensy 3.1 if you want.

[nk22]

Yeah, a microcontroller that is (at max) 10 mm thick, 60mm wide and 150mm tall would do it. And a screen of 65mmx27mm is needed. I was able to get a second calculator, even though it was completely ruined, so that i could see the measurements of the screen.

[adafruit_support_mike]

That's enough room for most of the small form-factor microcontroller boards, but if you want the device to be portable, also make sure to include room for batteries in your design,

I don't think we have any displays with the dimensions you listed in the shop. Go ahead and look through them to see if you can find anything that looks like it might work though:

https://www.adafruit.com/category/63