Garmin shows 0.0 speed sent by esp32 over BLE

Hi..

I've been working on esp32 project to get treadmill speed sent to my Gamin Fenix5.

The idea is simple. Esp32 reads the speed from flywheel via reed relay and transmits the speed data over BLE to my watch. The Garmin connects to esp32 but doesn't show the speed. The reading is 0.0.

nRF connect shows this:

nRF Connect, 2022-03-20
Footpod(3C:61:05:30:B2:06)
V 08:45:07.813 Connecting to 3C:61:05:30:B2:06...
D 08:45:07.813 gatt = device.connectGatt(autoConnect = false, TRANSPORT_LE, preferred PHY = LE 1M)
D 08:45:08.039 [Callback] Connection state changed with status: 0 and new state: CONNECTED (2)
I 08:45:08.039 Connected to 3C:61:05:30:B2:06
D 08:45:08.065 [Broadcast] Action received: android.bluetooth.device.action.ACL_CONNECTED
I 08:45:08.412 Connection parameters updated (interval: 7.5ms, latency: 0, timeout: 5000ms)
V 08:45:08.751 Discovering services...
D 08:45:08.751 gatt.discoverServices()
D 08:45:08.771 [Callback] Services discovered with status: 0
I 08:45:08.771 Services discovered
V 08:45:08.776 Generic Attribute (0x1801)
- Service Changed [I] (0x2A05)
   Client Characteristic Configuration (0x2902)
Generic Access (0x1800)
- Device Name [R] (0x2A00)
- Appearance [R] (0x2A01)
- Central Address Resolution [R] (0x2AA6)
Running Speed and Cadence (0x1814)
- Sensor Location [R] (0x2A5D)
- RSC Measurement [N] (0x2A53)
   Characteristic User Description (0x2901)
   Client Characteristic Configuration (0x2902)
D 08:45:08.777 gatt.setCharacteristicNotification(00002a05-0000-1000-8000-00805f9b34fb, true)
D 08:45:08.780 gatt.setCharacteristicNotification(00002a53-0000-1000-8000-00805f9b34fb, true)
I 08:45:08.907 Connection parameters updated (interval: 35.0ms, latency: 0, timeout: 5000ms)
V 08:45:12.723 Enabling notifications for 00002a53-0000-1000-8000-00805f9b34fb
D 08:45:12.723 gatt.setCharacteristicNotification(00002a53-0000-1000-8000-00805f9b34fb, true)
D 08:45:12.725 gatt.writeDescriptor(00002902-0000-1000-8000-00805f9b34fb, value=0x0100)
I 08:45:12.860 Data written to descr. 00002902-0000-1000-8000-00805f9b34fb, value: (0x) 01-00
A 08:45:12.860 "Notifications enabled" sent
V 08:45:12.868 Notifications enabled for 00002a53-0000-1000-8000-00805f9b34fb
I 08:45:13.916 Notification received from 00002a53-0000-1000-8000-00805f9b34fb, value: (0x) 03-BB-06-01-01-00-0A-00-00-00
A 08:45:13.916 "Speed: 6.73 m/s, Candence: 1 RPM,
Instantaneous Stride Length: 0.01 m,
Total Distance: 1.0 m,

Speed is sent but Garmin won't show it.

I believe something is missing from BLE characteristics.

Any idea?

Thanks.

mzypt over 3 years ago

Maybe Garmin needs more than just these characteristic?

Running Speed and Cadence (0x1814)
- Sensor Location [R] (0x2A5D)
- RSC Measurement [N] (0x2A53)
Characteristic User Description (0x2901)

mzypt over 3 years ago

I dont't have real footpod to compare but atleast Garmin HRM sends far more stuff than my esp32 "footpod"

8:37:37.882 Generic Access (0x1800)

- Device Name [R] (0x2A00)

- Appearance [R] (0x2A01)

- Peripheral Preferred Connection Parameters [R] (0x2A04)

- Central Address Resolution [R] (0x2AA6)

Generic Attribute (0x1801)

- Service Changed [I] (0x2A05)

Client Characteristic Configuration (0x2902)

Unknown Service (6a4e2401-667b-11e3-949a-0800200c9a66)

- Unknown Characteristic [N] (6a4ecd28-667b-11e3-949a-0800200c9a66)

Client Characteristic Configuration (0x2902)

- Unknown Characteristic [WNR] (6a4e4c80-667b-11e3-949a-0800200c9a66)

Device Information (0x180A)

- Manufacturer Name String [R] (0x2A29)

- Model Number String [R] (0x2A24)

- Serial Number String [R] (0x2A25)

- Hardware Revision String [R] (0x2A27)

- Firmware Revision String [R] (0x2A26)

- Software Revision String [R] (0x2A28)

Battery Service (0x180F)

- Battery Level [R] (0x2A19)

Heart Rate (0x180D)

- Heart Rate Measurement [N] (0x2A37)

Client Characteristic Configuration (0x2902)

- Body Sensor Location [R] (0x2A38)

jim_m_58 over 3 years ago in reply to mzypt

When your app is scanning, does it see it and then pair? Until that happens you can't read any characteristics.

See https://forums.garmin.com/developer/connect-iq/w/wiki/19/getting-started-with-connect-iq-ble-development

Also, the Nordic Thiny52 samples in the SDK. I would suggest getting the Nordic nRF52 DK (~$40US) or nRF52840 dongle (~$12US) so you can debug/test in the CIQ sim.

Make sure you are looking for the correct UUID. You need to use the proper base UUID. Here's the heartrate service (180D) and characteristic (2a37) for example

var HR_SERVICE = Ble.longToUuid(0x0000180D00001000L, 0x800000805F9B34FBL);
var HR_CHAR = Ble.longToUuid(0x00002a3700001000L, 0x800000805F9B34FBL);

Here's a test app you can use on your watch to make sure it can see your device and not just nRfConnect:

BleScan: https://apps.garmin.com/en-US/apps/9bcc8b66-8385-4afb-b93e-f69e01422284

and a blog post I did for interfacing with a Raspberry Pi: https://forums.garmin.com/developer/connect-iq/b/news-announcements/posts/would-you-like-some-raspberry-pi-with-your-connect-iq

mzypt over 3 years ago in reply to jim_m_58

BOTH nRF connect AND my Garmin can see and Pair the ESP32. But Garmin does NOT show the speed. nRF can see it

mzypt said:
08:45:13.916 "Speed: 6.73

jim_m_58 over 3 years ago in reply to mzypt

Are you doing reads or have you enabled notify for the characteristic? Are you getting the data in onCharacteristicRead() or onCharacteristicChanged() and maybe just not using the byte array correctly?

jim_m_58 over 3 years ago in reply to mzypt

You have the UUIDs for the service and characteristic defined when you do the BluetoothLowEnergy,registerProfile(), correct?

mzypt over 3 years ago in reply to jim_m_58

But something must be correct since nRF app reads the speed just fine. Maybe some Garmin proprietary data is missing?

mzypt over 3 years ago in reply to jim_m_58

jim_m_58 said:
You have the UUIDs for the service and characteristic defined when you do the BluetoothLowEnergy,registerProfile(), correct?

Correct. And for nRF it shows the speed. I also installed zwift..and it shows the speed.

The Garmin also pairs but the speed shows only zero value 0.0 as in photo

jim_m_58 over 3 years ago in reply to mzypt

What about doing a read vs notify?

jim_m_58 over 3 years ago in reply to mzypt

With nRFConnect, you can do both reads and notifies.

If you don't have the HW to test this in the sim, add println calls, build a sideload, and create the needed log file.