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Python script for tuning rtl_fm using input from WxToImg
#!/usr/bin/python3
import serial
import socket
import time
import subprocess
"""
DC0;SQ0000;FA00137100000;MD4;FA00137102450;FA00137102440;FA00137102436;...
Sent over serial by WxToImg for doppler tuning if below is set;
Options > Recording Options >
receiver type = Kenwood
receiver port = /dev/ttyAMA0
receiver baud rate = 9600
Short Raspberry Pi UART TXD/RXD pins together
"""
IN_DEV = "/dev/ttyAMA0"
BAUD = 9600
END_MSG = ";"
RTL_RATE = "60k"
class rtl_fm_remote(object):
"""
For remote control of rtl_fm command line program
"""
def __init__(self,
host="localhost",
port=6020):
self._host = host
self._port = port
self._s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
self._s.connect((self._host, self._port))
def set_freq(self, freq):
self.send_cmd(0, freq)
def set_mode(self, mode):
self.send_cmd(1, mode)
def set_squelch(self, squelch):
self.send_cmd(2, squelch)
def set_gain(self, gain):
self.send_cmd(3, gain)
def send_cmd(self, cmd, param):
cmd_bytes = (cmd).to_bytes(1, "little")
param_bytes = (param).to_bytes(32, "little")
self._s.send(cmd_bytes + param_bytes)
def __del__(self):
self._s.close()
rtl_proc = None
play_proc = None
rtl_remote = None
last_rx_time = 0
ser = serial.Serial(port=IN_DEV, baudrate=BAUD)
buffer = ""
rx_freq = 0
while True:
time.sleep(.1)
buffer += ser.read(ser.inWaiting()).decode("UTF8")
if END_MSG in buffer:
lines = buffer.split(END_MSG)
buffer = ""
for line in lines:
if len(line) > 0 and line.startswith("FA"):
str_freq = line[2:]
if str_freq.isnumeric():
last_rx_time = time.time()
rx_freq = int(str_freq)
if rtl_proc is None:
rtl_cmd = ["rtl_fm", "-M", "fm", "-f", str(rx_freq), "-s", RTL_RATE, "-E", "deemp", "-F", "9"]
play_cmd = ["play", "-r", RTL_RATE, "-t", "raw", "-e", "s", "-b", "16", "-c", "1", "-V1", "-"]
rtl_proc = subprocess.Popen(rtl_cmd, stdout=subprocess.PIPE)
time.sleep(1)
play_proc = subprocess.Popen(play_cmd, stdin=rtl_proc.stdout)
time.sleep(1)
rtl_remote = rtl_fm_remote()
else:
rtl_remote.set_freq(rx_freq)
if rtl_proc is not None:
if time.time() - last_rx_time > 60:
del(rtl_remote)
rtl_remote = None
play_proc.kill()
play_proc.wait()
play_proc = None
rtl_proc.kill()
rtl_proc.wait()
rtl_proc = None
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