natediggity123 wrote: ↑
Wed May 15, 2019 3:21 am
I was wondering if it is possible to put a raspberry pi into a calculator and use the pi as a emulator and a calculator.
I'd use an RPI Zero.
The hardest aspects of these sorts of projects is interfacing the existing proprietary keyboard. Most calculator style keyboards are a simple crosspoint switch matrix. A keyboard of 6 rows of 4 keys, needs a 10 I/O (6 +4 = 10) lines, so it can chew up the RPI GPIO pins. I would look for a I2C GPIO extender to give you the extra I/O lines. Ti make a dedicated i2C controller chip (http://www.ti.com/lit/ds/symlink/lm8330.pdf
) for the purpose. I have seen $2 breakout modules on Banggood, for 8 x 12 matrix keyboards.