add timeout when waiting for weight to stabilize and separate callbac…

…ks for different characteristics

README.md

@@ -21,6 +21,7 @@ There also seem to be some identical scales with a different branding on the mar
 
 ## Versions / Changelog
 
+- v0.2.0: Wait for weight to stabilize with a timeout and add command line arguments
 - v0.1.1: Use asyncio.sleep() instead of dev. info requests to keep notifications incoming
 - v0.1.0: The client is able to get the weight from the scale.
 

src/crenot-gofit-s2.py

@@ -19,11 +19,13 @@ class CrenotGofitS2:
     print_svc_info = False
 
     is_weight_stable = False
+    wait_stable_timeout = 10
     weight           = 0 # in grams
 
-    def __init__(self, print_dev_info=False, print_svc_info=False):
+    def __init__(self, print_dev_info=False, print_svc_info=False, timeout=10):
         self.print_dev_info = print_dev_info
         self.print_svc_info = print_svc_info
+        self.wait_stable_timeout = timeout
 
     async def run(self):
         name = "Crenot Gofit S2"
@@ -38,16 +40,24 @@ async def run(self):
         if self.print_svc_info:
             await self.print_services()
 
-        await self.start_notification("FFB2")
-        # await self.start_notification("FFB3")
-        # await self.start_notification("2A05")
-
-        logging.info("Waiting for weight to stabilize")
-        while not self.is_weight_stable:
-            logging.debug(f"weight:{self.weight}")
-            await asyncio.sleep(1)
-
-        logging.info(f" - Weight: {self.weight/1000: .2f}kg")
+        await self.start_notification("FFB2", self.on_ffb2_notification)
+        # await self.start_notification("FFB3", self.on_ffb3_notification)
+        # await self.start_notification("2A05", self.on_2a05_notification)
+
+        logging.info(f"Waiting for weight to stabilize (timeout:{self.wait_stable_timeout}s)" )
+
+        try:
+            async with asyncio.timeout(self.wait_stable_timeout):
+                while not self.is_weight_stable:
+                    logging.debug(f"weight:{self.weight}")
+                    await asyncio.sleep(1)
+                logging.info(f" - Weight: {self.weight/1000: .2f}kg")
+        except asyncio.TimeoutError:
+            logging.error(f" - Timeout (Last weight: {self.weight/1000: .2f}kg)")
+        except asyncio.CancelledError:
+            logging.error(f" - Cancelled (Last weight: {self.weight/1000: .2f}kg)")
+        except Exception as e:    
+            logging.error("Waiting for stable weight failed with exception", e)
 
     ###
     # connect()
@@ -120,24 +130,30 @@ async def print_services(self):
     # start_notification()
     #  - triggers the scale to send notification/indication messages for the given uuid
     ###
-    async def start_notification(self, uuid):
+    async def start_notification(self, uuid, callback):
 
         logging.info(f"Starting notifications for uuid {uuid}")
-        await self.client.start_notify(uuid, self.notify_callback)
+        await self.client.start_notify(uuid, callback)
 
     ###
-    # notify_callback()
-    #  - called when notification/indication message is received
+    # on_xxxx_notififaction()
+    #  - called when notification/indication message of according uuid is received
     ###
-    async def notify_callback(self, sender: BleakGATTCharacteristic, data: bytearray):
-        logging.debug(f" - received data {data.hex()}")
+    async def on_ffb2_notification(self, sender: BleakGATTCharacteristic, data: bytearray):
+        logging.debug(f" - FFB2: received data {data.hex()}")
         if not self.is_weight_stable:
             # weight is stored in bytes 6, 7 and 8 but only 2 bits of byte 6 are used
             # therefore we extract the value by binary or operation 262143
             self.weight = int.from_bytes([ data[6], data[7], data[8] ]) & 262143
             if data[4] == 2:
                 self.is_weight_stable = True
 
+    async def on_ffb3_notification(self, sender: BleakGATTCharacteristic, data: bytearray):
+        logging.info(f" - FFB3: received data {data.hex()}")
+
+    async def on_2a05_notification(self, sender: BleakGATTCharacteristic, data: bytearray):
+        logging.info(f" - 2A05: received data {data.hex()}")
+
 
 
 # Execute when the not initialized from an import statement.
@@ -147,7 +163,10 @@ async def notify_callback(self, sender: BleakGATTCharacteristic, data: bytearray
     parser = argparse.ArgumentParser(description="Client application for 'Crenot Gofit S2' scale")
     parser.add_argument('--print_dev_info', action='store_true', help='enable output of device information')
     parser.add_argument('--print_svc_info', action='store_true', help='enable output of service information')
+    parser.add_argument('--timeout', type=float, default=10, help='timeout when waiting for weight to stabilize')
     args = parser.parse_args()
 
     logging.basicConfig(level=logging.INFO, format=" - %(levelname)s \t%(message)s")
-    asyncio.run(CrenotGofitS2(print_dev_info=args.print_dev_info, print_svc_info=args.print_svc_info).run())    
+    asyncio.run(CrenotGofitS2(print_dev_info=args.print_dev_info,
+                              print_svc_info=args.print_svc_info,
+                              timeout=args.timeout).run())