1  # SPDX-FileCopyrightText: 2020 Limor Fried for Adafruit Industries
 2  #
 3  # SPDX-License-Identifier: MIT
 4  
 5  import time
 6  import serial
 7  
 8  SERIAL_PORT = "/dev/ttyS15"   # or "COM4" or whatever
 9  
10  serialport = serial.Serial(SERIAL_PORT, 9600)
11  
12  
13  def read_me007ys(ser, timeout = 1.0):
14      ts = time.monotonic()
15      buf = bytearray(3)
16      idx = 0
17  
18      while True:
19          # Option 1, we time out while waiting to get valid data
20          if time.monotonic() - ts > timeout:
21              raise RuntimeError("Timed out waiting for data")
22  
23          c = ser.read(1)[0]
24          #print(c)
25          if idx == 0 and c == 0xFF:
26              buf[0] = c
27              idx = idx + 1
28          elif 0 < idx < 3:
29              buf[idx] = c
30              idx = idx + 1
31          else:
32              chksum = sum(buf) & 0xFF
33              if chksum == c:
34                  return (buf[1] << 8) + buf[2]
35              idx = 0
36      return None
37  
38  while True:
39      dist = read_me007ys(serialport)
40      print("Distance = %d mm" % dist)