import serial
import time

def sendCommands(cmds, delay=0):
   for cmd in cmds.strip().splitlines():
       cmd = cmd.strip()
       print('Sending: ' + cmd)
       cmd = cmd + '\n'

       s.write(cmd.encode()) # Send g-code block to grbl

       if (delay != 0):
           time.sleep(delay)

       while True:
           grbl_out_raw = s.readline()
           grbl_out = grbl_out_raw.decode('utf-8').strip()
           print(grbl_out)
           if grbl_out == 'ok':
               break

def homeDevice():
   cmd = """
           $$
           $H
           G10 P0 L20 X0 Y0 Z0
           """
   sendCommands(cmd)


def pyramidPattern():
   cmd=''
   # Count up to 600
   for i in range(100,700,100):
       cmd += """
               G0 X{0}
               ?
               """.format(i)

   # Count down to 100
   for i in range(500,0,-100):
       cmd += """
               G0 X{0}
               ?
               """.format(i)
   sendCommands(cmd, delay=0)


# Open grbl serial port
s = serial.Serial('/dev/cu.usbmodem146401',115200)

# Wake up grbl
serialCmd = "\r\n\r\n"
s.write(serialCmd.encode())
time.sleep(2)   # Wait for grbl to initialize
s.flushInput()  # Flush startup text in serial input

homeDevice()
pyramidPattern()