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View Full Version : Old Calculator LCD interfacing



vigyan
06-03-2008, 09:28 AM
Is it possible to interface LCDs from old calculators, wrist watches etc ?

Battery
06-03-2008, 10:31 AM
Calculators and all normal devices have segemented display where every segment is run by some specific voltage level curve having 3 different voltage levels. Google "Segmented LCD" and you will get the exact details.

The good thing about this lcd's is they are too cheap in cost. May be you will get standard 80 segment lcd at just Rs.10!!! Hence most of electronic gadgets prefer them instead of character or graphic lcd.

One solution is you make your own hardware for generating different voltage levels and switch them with software to get the curve. But mind that is too difficult.

Another solution is you use Segmented LCD driver MCU's or extra driver chips. If anyone knows avr butterfly they use this kind of lcd's with ATMega169(with inbuilt support for segmented lcd driver). Also some PIC microcontrollers have it inbuilt. Also driver chip from PIC is available for the same.

vigyan
06-03-2008, 04:20 PM
Thank you Battery for your valuable information.

docel
06-03-2008, 09:58 PM
Check out CD4543 datasheet.....