button.py

import time
import serial
import RPi.GPIO as GPIO

# Set up gpio for button push
PIN_NUM = 7
GPIO.setwarnings(False)
GPIO.setmode(GPIO.BOARD)

# Set up printer
ser = serial.Serial('/dev/serial0', 19200)

# To write to serial port do:
# ser.write(b'Your text here\n\n')



GPIO.setup(PIN_NUM, GPIO.IN, pull_up_down=GPIO.PUD_DOWN)


def main():
  while True:
    if GPIO.input(PIN_NUM) == GPIO.HIGH:
      ser.write(b'button pushed!\n\n')
    time.sleep(.5)

main()