[python] tool to read data from hotwire anemometer PCE-423 (#2851)

sw/ground_segment/python/anemometer_PCE423.py

@@ -0,0 +1,124 @@
+#!/usr/bin/python3
+#
+# This file is part of PPRZLINK.
+# 
+# PPRZLINK is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# PPRZLINK is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with PPRZLINK.  If not, see <https://www.gnu.org/licenses/>.
+#
+
+#
+# capture data from hot-wire anemometer PCE-423 (through USB cable)
+# 
+
+import serial
+import struct
+import logging
+import time
+
+logger = logging.getLogger("anemometer_PCE423")
+
+STX_A = 0xAA
+STX_B = 0xBB
+
+STATE_SYNC = 0
+STATE_GOT_A = 1
+STATE_GOT_B = 2
+
+FRAME_LENGTH = 80
+DATA_LENGTH = FRAME_LENGTH - 2 # frame - STX
+
+PCE423_BAUDRATE = 9600
+
+class AnemometerPCE423():
+    def __init__(self, device='/dev/ttyUSB0', callback=None):
+        self.state = STATE_SYNC
+        self.callback = callback
+        self.running = True
+        self.speed = 0. # airspeed in m/s
+        self.temperature = 0. # temperature in °C
+        self.line_1 = 0. # data displayed on line 1
+        self.line_2 = 0. # data displayed on line 2
+        self.time = 0. # timestamp
+        try:
+            self.ser = serial.Serial(device, PCE423_BAUDRATE)
+        except:
+            logging.error("unable to open serial port '{}'".format(device))
+            exit(0)
+
+    def stop(self):
+        logger.info("Stop reading PCE-423")
+        self.running = False
+        self.ser.close()
+
+    def __del__(self):
+        try:
+            self.ser.close()
+        except:
+            pass
+
+    def run(self):
+        """Star reading frames from PCE-423"""
+        while self.running:
+            c = self.ser.read(1) # read data to find sync bytes
+            b = struct.unpack("B", c)[0]
+            if self.state == STATE_SYNC and b == STX_A:
+                self.state = STATE_GOT_A
+            elif self.state == STATE_GOT_A:
+                if b == STX_B:
+                    self.state = STATE_GOT_B
+
+                    # sync OK
+                    self.time = time.time()
+                    data = self.ser.read(DATA_LENGTH)
+                    if len(data) >= DATA_LENGTH:
+                        sub = data[0:4*4]
+                        self.line_1, self.line_2, self.speed, self.temperature = struct.unpack('ffff', sub)
+                        if self.callback is not None:
+                            self.callback(self.time, self.speed, self.temperature)
+                        logging.debug('{:f} {:f} {:f} {:f}'.format(self.line_1, self.line_2, self.speed, self.temperature))
+                    else:
+                        # error, not enough data
+                        logging.error("frame error")
+                    # goto sync
+                    self.state = STATE_SYNC
+                else:
+                    # sync error, b != STB_B
+                    self.state = STATE_SYNC
+            else:
+                logging.info("wait sync")
+
+    def get_speed(self):
+        return self.speed
+
+    def get_temperature(self):
+        return self.temperature
+
+
+if __name__ == '__main__':
+    import argparse
+
+    parser = argparse.ArgumentParser()
+    parser.add_argument("-d", "--device", help="device name", dest='dev', default='/dev/ttyUSB0')
+    args = parser.parse_args()
+
+    def cb(time, speed, temp):
+        print("time: {:.2f}, speed: {:.4f}, temperature: {:.2f}".format(time, speed, temp))
+
+    print("Starting interface for PCE-423 anemometer")
+    pce423 = AnemometerPCE423(args.dev, cb)
+    try:
+        pce423.run()
+    except (KeyboardInterrupt, SystemExit):
+        print('Shutting down...')
+        pce423.stop()
+