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#!/usr/bin/env python3
#
# Copyright 2020 Birte Kristina Friesel
#
# SPDX-License-Identifier: BSD-2-Clause
import numpy as np
import re
import requests
import serial
import serial.threaded
import sys
import time
class SerialReader(serial.threaded.Protocol):
"""
Character- to line-wise data buffer for serial interfaces.
Reads in new data whenever it becomes available and exposes a line-based
interface to applications.
"""
def __init__(self, callback):
"""Create a new SerialReader object."""
self.callback = callback
self.recv_buf = ''
def __call__(self):
return self
def data_received(self, data):
"""Append newly received serial data to the line buffer."""
try:
str_data = data.decode('UTF-8')
self.recv_buf += str_data
# We may get anything between \r\n, \n\r and simple \n newlines.
# We assume that \n is always present and use str.strip to remove leading/trailing \r symbols
# Note: Do not call str.strip on lines[-1]! Otherwise, lines may be mangled
lines = self.recv_buf.split('\n')
if len(lines) > 1:
self.recv_buf = lines[-1]
for line in lines[:-1]:
self.callback(str.strip(line))
except UnicodeDecodeError:
pass
#sys.stderr.write('UART output contains garbage: {data}\n'.format(data = data))
class SerialMonitor:
"""SerialMonitor captures serial output for a specific amount of time."""
def __init__(self, port: str, baud: int, callback):
"""
Create a new SerialMonitor connected to port at the specified baud rate.
Communication uses no parity, no flow control, and one stop bit.
Data collection starts immediately.
"""
self.ser = serial.serial_for_url(port, do_not_open=True)
self.ser.baudrate = baud
self.ser.parity = 'N'
self.ser.rtscts = False
self.ser.xonxoff = False
try:
self.ser.open()
except serial.SerialException as e:
sys.stderr.write('Could not open serial port {}: {}\n'.format(self.ser.name, e))
sys.exit(1)
self.reader = SerialReader(callback = callback)
self.worker = serial.threaded.ReaderThread(self.ser, self.reader)
self.worker.start()
def close(self):
"""Close serial connection."""
self.worker.stop()
self.ser.close()
if __name__ == '__main__':
got_data = False
step = 0
def parse_line(line):
global got_data
match = re.match('Anemometer Count = ([^ ]+)', line)
if match:
got_data = True
wind_clicks = float(match.group(1))
windspeed_kmh = wind_clicks * 2.4 / 10
requests.post('http://influxdb:8086/write?db=sensors', data='anemometer,area=hm17_,location=balkon windspeed_kmh={}'.format(windspeed_kmh))
monitor = SerialMonitor('/dev/serial/by-path/platform-fd500000.pcie-pci-0000:01:00.0-usb-0:1.1:1.0-port0', 57600, parse_line)
try:
while True:
time.sleep(5)
step += 1
if step == 4:
if not got_data:
print('Error: received no data for 20 seconds', file=sys.stderr)
sys.exit(1)
got_data = False
step = 0
except KeyboardInterrupt:
monitor.close()
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