feat: make --device flag optional with 'any' default

When --device is omitted or set to 0, the bridge listens to all
broadcasting ANT+ trainers instead of filtering by a specific device.
The actual transmitting device ID is shown in data logs, allowing
users to discover and then filter specific trainers.

Also fix vendorID/productID not being assigned to config struct
which caused ListenForTrainer to receive 0 for both values.

README.md

@@ -119,13 +119,13 @@ The binary is built to `bin/bridge`.
 ## Usage
 
 ```bash
-# Use defaults (device 3001)
+# Listen to all trainers (default)
 sudo ./bin/bridge
 
-# Custom trainer device
+# Filter for a specific trainer
 sudo ./bin/bridge --device 0xbb9
 
-# Custom vendor/product IDs
+# Custom vendor/product IDs with specific device
 sudo ./bin/bridge --vendor 0x0fcf --product 0x1008 --device 3001
 ```
 
@@ -135,14 +135,14 @@ sudo ./bin/bridge --vendor 0x0fcf --product 0x1008 --device 3001
 |------|---------|-------------|
 | `--vendor` | `0x0fcf` | USB vendor ID (hex or decimal, e.g. `0x0fcf` or `4047`) |
 | `--product` | `0x1008` | USB product ID (hex or decimal) |
-| `--device` | `3001` | ANT+ device number (hex or decimal, e.g. `3001` or `0xbb9`) |
+| `--device` | `0 (any)` | ANT+ device number (hex or decimal). Use 0 or omit to listen to all devices |
 | `--help` | | Show help |
 | `--version` | | Show version info |
 
 ## Finding your trainer's ANT+ device number
 
-Most ANT+ cycling power trainers use device number `3001` (decimal) or `0xbb9` (hex). If that works, you can use the 
+The bridge listens to all broadcasting devices by default. When multiple ANT+ trainers are nearby, each will appear in the 
-bridge with default settings.
+log output as `ant: <device_id>: power: ...`. Use `--device <id>` to filter for a specific trainer.
 
 If you're unsure of your trainer's device number, you can discover it using another ANT+ device (e.g., a Garmin Edge 
 head unit). Connect the Garmin to your trainer and look for the device number in the ANT+ sensor list.
@@ -179,11 +179,14 @@ Your trainer's power and cadence data should now be available in the app.
 
 ```
 2026-05-26 11:00:34 ANT Bridge abc1234 built 2026-05-26T11:00:00
-2026-05-26 11:00:34 vendor: 0x0fcf/4047
+2026-05-26 11:00:34 usb: vendor: 0x0fcf/4047
-2026-05-26 11:00:34 product: 0x1008/4104
+2026-05-26 11:00:34 usb: product: 0x1008/4104
-2026-05-26 11:00:34 device: 0xbb9/3001
+2026-05-26 11:00:34 ant: device: any
-2026-05-26 11:00:34 BLE advertising...
+2026-05-26 11:00:34 ant: device opened
-2026-05-26 11:00:34 bt: watts: 150  rpm: 80  completedRevs: 1234  lastRevTime: 4890
+2026-05-26 11:00:34 bt: BLE advertising...
+2026-05-26 11:00:34 ant: scan mode started
+2026-05-26 11:00:34 ant: listening...
+2026-05-26 11:00:35 ant: 3001: power: 150W  cadence: 80 rpm
 ```
 
 The bridge logs a lot of output during normal operation — this is expected and helpful for debugging during this early 
@@ -191,9 +194,14 @@ stage of development.
 
 Key log lines:
 - `ANT Bridge ...` — Startup message with version and build time
-- `vendor: ...` / `product: ...` / `device: ...` — Configuration being used
+- `usb: vendor: ...` / `usb: product: ...` — USB dongle configuration
-- `BLE advertising...` — BLE service is ready and visible to other devices
+- `ant: device: ...` — ANT+ device filter (or `any` if listening to all devices)
-- `bt: watts: ...` — Power and cadence data being broadcast
+- `ant: device opened` — USB dongle opened successfully
+- `bt: BLE advertising...` — BLE service is ready and visible to other devices
+- `ant: scan mode started` / `ant: listening...` — ANT+ receiver is active
+- `ant: <id>: power: ...` — Power/cadence data with transmitting device ID
+- `bt: watts: ...` — Power/cadence data being broadcast over BLE
+- `ant: received msg from ignored device ...` — Message from non-matching device (when `--device` is specified)
 - `hciconfig ... failed` — Bluetooth adapter reset warnings (usually harmless)
 
 ## Development
@@ -230,10 +238,10 @@ make clean    # Remove build artifacts
 - Make sure the trainer is turned on and broadcasting
 - Use another device (e.g. Garmin Edge) to verify it is broadcasting. This also provides a way
   to get the device id.
+- The bridge listens to all devices by default. If multiple trainers are broadcasting, use
+  `--device <id>` to filter for a specific one
 - Make sure the dongle is close enough to the trainer (within 1-2 meters)
-- Verify the device number is correct (try `--device 3001`)
 - Check the log output for the `listening...` message
-- Try a different device number if available
 
 ### BLE connection drops
 

cmd/bridge/ant.go

@@ -56,8 +56,8 @@ func ListenForTrainer(vendorId uint16, productId uint16, deviceNumber uint32,
 
 	logMsg("ant: listening...")
 	for msg := range msgs {
-		if msg.DeviceNumber() != deviceNumber {
+		if deviceNumber != 0 && msg.DeviceNumber() != deviceNumber {
-			logPrintf("Received msg from ignored ant+ device %v\n", msg.DeviceNumber())
+			logPrintf("ant: received msg from ignored device %v\n", msg.DeviceNumber())
 			continue
 		}
 		//fmt.Printf("raw msg: device type=0x%02x device number=%d content=%x\n",

cmd/bridge/cli.go

@@ -52,19 +52,26 @@ This allows these trainers to be used with modern devices that don't support ANT
 			if err != nil {
 				return fmt.Errorf("invalid --product %q: %w", c.product, err)
 			}
-			deviceNumber, err := parseHex(c.device, 32)
+			c.vendorID = uint64(vendorID)
-			if err != nil {
+			c.productID = uint64(productID)
-				return fmt.Errorf("invalid --device %q: %w", c.device, err)
+			if c.device != "" {
+				deviceNumber, err := parseHex(c.device, 32)
+				if err != nil {
+					return fmt.Errorf("invalid --device %q: %w", c.device, err)
+				}
+				c.deviceNumber = uint32(deviceNumber)
 			}
 
-			c.vendorID = vendorID
+			deviceNumber := c.deviceNumber
-			c.productID = productID
-			c.deviceNumber = uint32(deviceNumber)
 
 			logMsgf("ANT Bridge %s built %s", Version, BuildTime)
 			logMsgf("usb: vendor: 0x%04x/%d", vendorID, vendorID)
 			logMsgf("usb: product: 0x%04x/%d", productID, productID)
-			logMsgf("ant: device: 0x%03x/%d", deviceNumber, deviceNumber)
+			if deviceNumber == 0 {
+				logMsgf("ant: device: any")
+			} else {
+				logMsgf("ant: device: 0x%03x/%d", deviceNumber, deviceNumber)
+			}
 
 			if err := exec.Command("hciconfig", "hci0", "down").Run(); err != nil {
 				logPrintf("bt: hciconfig down failed: %v\n", err)
@@ -83,7 +90,7 @@ This allows these trainers to be used with modern devices that don't support ANT
 
 	rootCmd.Flags().String("vendor", "0x0fcf", "USB vendor ID (hex, e.g. 0x0fcf)")
 	rootCmd.Flags().String("product", "0x1008", "USB product ID (hex, e.g. 0x1008)")
-	rootCmd.Flags().String("device", "3001", "ANT+ device number (hex or decimal, e.g. 3001 or 0xbb9)")
+	rootCmd.Flags().String("device", "", "ANT+ device number (hex or decimal). Use 0 or omit to listen to all devices")
 	if err := rootCmd.Execute(); err != nil {
 		os.Exit(1)
 	}