Torque and phase via bluetooth in Vector 3 power meter?

3919339 over 3 years ago

I am trying to get an advanced power data from Garmin Vector 3 power meter pedals via bluetooth protocol and it seems only basic stuff is available (such as power values, power balance and cadence). With that it seems Garmin own apps can extract way more out of Vector 3 (not sure if only via ANT+ or via BT as well with some secret characteristics). Any help with that subject will be highly appreciated!

jim_m_58 over 3 years ago

Not sure about ANT vs BLE, but in the case of the HRM-PRO, not everything available with ANT is available with BT.

Have you tried using Nordic's RfConnect to look at the service and characteristics?

3919339 over 3 years ago in reply to jim_m_58

I was using Power Cycling Features characteristic (2A65) and I've got only following (in 32 bit info word):

Pedal Power Balance Supported (bit 0)
Crank Revolution Data Supported (bit 3)
Offset Compensation Supported (bit 9)
Crank Length Adjustment Supported (bit 12)
Sensor Measurement Context (bit 16)
Distribute System Support (bit 20 and 21 - value is 1 = Not for use in a distributed system)

I presume the main issue is - frequency of data flow via bluetooth is too low to get real-time torques in various rotation angles... But if there is some way to get average angle for max torque or something like this - it would be very helpful...

3919339 over 3 years ago in reply to 3919339

Vector 3 only advartises following characteristics upon discovery: 2A65 (0x2), 2A63(0x10), 2A5D (0x2) and 2A66 (0x28)

jim_m_58 over 3 years ago in reply to 3919339

Using CIQ BLE, when you read a characteristic, you only see at most 22 bytes, no matter how much is sent.

3919339 over 3 years ago in reply to jim_m_58

I was not using SDKs - was using raw Bluetooth layer (in Apple iOS device). It allow to read anything which was supplied. Didn't have any issues with truncation of data... But it appears that advanced data just not provided by Bluetooth server (e.g. pedals' bluetooth HW/Firmware combo)... So I was thinking - maybe there is some secret ability to enable it via sending some code to 2A66 characteristic)? Or some characteristic that is not advertised, but knowing its GUID can be connected?

jim_m_58 over 3 years ago in reply to 3919339

As I've said, in the case of the HRM-PRO, there is data available with ANT that's not with BLE. ANT is the preferred method for that device.

jim_m_58 over 3 years ago in reply to jim_m_58

As what you want to do doesn't involve Connect IQ, have you tried asking in the Vector 3 forum?

https://forums.garmin.com/sports-fitness/cycling/f/vector-3

3919339 over 3 years ago in reply to jim_m_58

I haven't. Thank you for the suggestion! Will do now.