This project interfaces a mechanical typewriter to a Raspberry Pi using a SoftPot touch sensor.

adc_spi.py: Microchip MCP3008 analog-to-digital converter interface. Bit-bangs SPI on Raspberry Pi GPIO pins. Based on code from Adafruit.

ttypewriter.py: Typewriter calibration and keypress decoding.

Run sudo python ttypewriter.py -c and press each key when prompted to create the calibration file.
Run sudo python ttypewriter.py to decode keypresses and write characters to stdout.
Open a screen session with sudo screen -S <session_name> and run sudo python ttypewriter.py -S <session_name> to decode keypresses and inject characters into the screen session.

Usage: ttypewriter.py [options]

Options:
  -h, --help            show this help message and exit
  -d, --debugraw        print raw adc values
  -c, --cal             perform calibration
  -f CALFILE, --calfile=CALFILE
                        calibration file to use
  -S SESSION, --session=SESSION
                        screen session to receive keypresses
  -v, --verbose         debugging verbosity v:info vv:debug