import serial, time
com = serial.Serial('/dev/ttyACM0', 1000000, timeout=1)

lines=[]

f = open("data.txt", "w")

time.sleep(1)

# serial commands
# space=idle state, m=measure, f=field commute

def sendCmd(txt):
    time.sleep(0.05)
    com.write(txt.encode("utf-8"))

measLen=10000

# measure idle values
sendCmd('m')

for n in range(1,measLen):
    line = com.readline()
    lines.append(line)
    
# turn on field commutation
sendCmd('f')

for n in range(1,measLen):
    line = com.readline()
    lines.append(line)

# turn of power and measure deceleration 
sendCmd(' ')
sendCmd('m')

for n in range(1,measLen*3):
    line = com.readline()
    lines.append(line)

# go to idle state
txt=' '
com.write(txt.encode("utf-8"))

for line in lines:
    txt=line.decode("utf-8")
    print(txt)
    f.write(txt)

com.close();
f.close()