Send small amount of data from Edge 840 back to phone?

Dan 5 days ago

I created a DataField app for the Edge 840, which listens to ANT+ button events. This works great during my bike rides.

Now I wish to extend it, and control a Bluetooth Classic device (Sena Bikom 20) when a specific ANT+ button event comes in.

AFAIK Bluetooth Classic is impossible to use in user softwares. Is it true?

So I checked other options: DataField can NOT use Communications, is this true? More precisely it can only use it with at least 5 min delay.

BLE connections are possible, but it makes things harder: I have to create a phone app acting as a BLE Central exposing Characteristics for the DataField.

Is there any better approach I can use? Please note I need to use this when I'm running an activity, and Data Screen is active. Maybe I can have an app with background operations while it's not on the screen? Is it possible?

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jim_m_58 5 days ago in reply to Dan +1

With blescan you can try a simple connect. With nrfconnect, you can see services and characteristics. with CIQ you can turn on notify to a characteristic and write to one.

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jim_m_58 5 days ago

Try my blescan app and see if it sees the Sena device. If it does, your DF can probably talk to the sena directly - no phone involved. I have DFs that talk BLE for a couple different sensors

BleScan | Connect IQ Store

In the SDK samples, NordicThingy52CoinCollector is a DF that talks BLE.

Dan 5 days ago in reply to jim_m_58

jim_m_58 : worldclass reaction speed! Thank you

Sena (unfortunately) uses Classic BT, with RFCOMM (Bluetooth SPP). I managed to reverse-engineer their protocol, and I can control it with this app: https://play.google.com/store/apps/details?id=de.kai_morich.serial_bluetooth_terminal&pli=1

So no BLE control is known / available. Therefore I thought on sending back the button event to my phone, and just simply send the magic bytes to BT classic SPP to Sena.

jim_m_58 5 days ago in reply to Dan

So no BLE? Just BT? Did you try blescan on your 840?

Dan 5 days ago in reply to jim_m_58

It seems so yes. It actually has BLE, but I have no idea on how can I control it via BLE. I scanned it with my phone (nRF Connect):

Dan 5 days ago in reply to Dan

Do you have any idea what would worth trying via BLE? I also feel it would be much more feasible to connect directly to Sena from Edge.

Dan 5 days ago in reply to Dan

Wow! I managed to control it via BLE!

But there are 3 steps:

Connect to it
Enable notifications on a specific UUID
Send GATT Write

jim_m_58 5 days ago in reply to Dan

With blescan you can try a simple connect. With nrfconnect, you can see services and characteristics. with CIQ you can turn on notify to a characteristic and write to one.

Dan 4 days ago in reply to jim_m_58

By any chance: do you have a sample code for connecting and enabling notifications? I tried various methods, but "BluetoothLowEnergy.registerProfile" crashes for me on Edge 840.