Hacking a citizen's calculator..???

Question

I want to know how I can interface the calculator keypad to any of the micro controller and its display with any protocol if possible. Generally these chips are fixed with epoxy glues inside hence its difficult to get the inside IC details.

Any help in this regard is appreciated....

kidiccurus · Answer

Good luck finding one that uses a serial keypad, I have opened many calculators in my time and not one has had a serial interface. The only way I can see you reverse engineering it is mannualy following the traces and addind your own micro to interpret the signals. Even then, you would have to replace the screen as those things are a nightmare to hack. Trust me, I am speaking from experience. With all this effort you are probably better off building your own.

dr.akshay_1980@yahoo.com · Answer

Hi Clem,

I was indeed curious to know the internals of calculators' from citizen or any other company and might land up finding a new protocol for keyboard or display which can be helpful for small embedded systems. I want keypad's and display's protocol/connections/datasheet and will be happy to write the drivers from scratch even for the simple 8 bit controllers. This ready made package might be helpful in implementing the interface devices with controllers.... Out of curiosity in past I started digging up with the calculators.. not much successful in today's date.....

In case you find other good resource do share it...

bye...

Thanks once again for your wonderful replies...

Hacking a citizen's calculator..???

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