import time,board

def read_id(pin):

	L1 = board.pin(pin, board.GPIO.IN, board.GPIO.PULL_UP)	
	a = []
	t1 = time.ticks_us()
	while L1.value() == 1:
		t2 = time.ticks_us()
		if time.ticks_diff(t2, t1) >1000000:
			#raise ValueError("[MixNo]:Sensor read error")
			break
		pass

	time.sleep_us(13560)	

	for i in range(1000):		
		v = L1.value()
		a.append(v)
		time.sleep_us(56)

	a_c = []
	count = 0

	for i in a:	
		if i == 1:
			count += 1

		elif i == 0:
			if count > 0 :
				a_c.append(count)
			count =0

	for i in range(len(a_c)):
		if a_c[i] > 10:
			a_c[i] = "1"
		else:
			a_c[i] = "0"
			
	B1 = "".join(a_c)
	B2 = B1[16:32]
	#print(len(B1))
	if len(B1)==32 or len(B1)==33 or len(B1)==46:
		B3=int(B2,2)
		return B3
	else:
		return None