Merge pull request #190 from mexon/sample-python-script

Add Python program to scan for reflashed LYWSD03MMC

contrib/python/README.md

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+# Quick Thermometer scan in Python
+
+This is intended as a demo of how to read BLE announcements in Python.  It is based on [bluepy](https://github.com/IanHarvey/bluepy).
+
+## Usage
+
+```
+❯ pip3 install bluepy
+[...]
+❯ python3 scan-thermometer.py
+{"timestamp": "2021-06-10T20:36:50+02:00", "mac": "A4:C1:38:XX:XX:XX", "temperature": 23.4, "humidity": 52, "battery_percent": 85, "battery_volt": 0.328, "count": 22}
+```
+
+The program terminates after reading one value, or after 10s.
+
+The scan is performed in passive mode.

contrib/python/scan-thermometer.py

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+from bluepy.btle import Scanner, DefaultDelegate, BTLEInternalError
+import json
+from datetime import datetime
+
+class ScanDelegate(DefaultDelegate):
+    def __init__(self):
+        DefaultDelegate.__init__(self)
+
+    def handleDiscovery(self, dev, isNewDev, isNewData):
+        for (sdid, desc, val) in dev.getScanData():
+            if self.isTemperature(dev.addr, sdid, val):
+                print(json.dumps(self.parseData(val)))
+                exit()
+
+    def isTemperature(self, addr, sdid, val):
+        if sdid != 22:
+            return False
+        if len(val) != 30:
+            return False
+        return True
+
+    def parseData(self, val):
+        bytes = [int(val[i:i+2], 16) for i in range(0, len(val), 2)]
+        return {
+            'timestamp': datetime.now().astimezone().replace(microsecond=0).isoformat(),
+            'mac': ":".join(["{:02X}".format(bytes[i]) for i in range(2,8)]),
+            'temperature': (bytes[8] * 16 + bytes[9]) / 10,
+            'humidity': bytes[10],
+            'battery_percent': bytes[11],
+            'battery_volt': (bytes[12] * 16 + bytes[13]) / 1000,
+            'count': bytes[14],
+        }
+
+scanner = Scanner().withDelegate(ScanDelegate())
+scanner.scan(10.0, passive=True)