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BLE4 as a RFCOMM/serial interface for $RC2/$RC3

edited August 23 in DIY builds
Hello,
i have an Arduino prototype for my car project and one of the features is to read raw CAN-bus data and send it via Bluetooth to Racechrono for logging.

The issue is that i cannot connect to my BLE4 device (HM-10 clone with CC2541 chip) from Racechrono. However, with the same setup, i was able to get it working with older Bluetooth2 and HC-05 module without issues, but connecting with RFCOMM method from Racechrono.

My findings:
I have the same issue as in this thread: https://racechrono.com/forum/discussion/1590/diy-data-collection-with-link-to-working-code-for-arduino-and-bluetooth
Cite: "tried AT09 (BT4/BLE) module in stead of HC05 (BT2). When using "Serial Bluetooth Terminal" on my Android phone I can see data is arriving (same with AT09 as with HC05), but with AT09: RaceChrono (on the same phone) always and forever get stuck with message "Connecting to Data logger..." and "Connecting... (waiting)"."

I'm able to connect via BLE if i change the UUID of my module to the one mentioned in your DYI:00001ff8-0000-1000-8000-00805f9b34fb
but then, i have only option of CAN-BUS and GPS. But i need the RFCOMM/Serial (RC2/RC3) option.

Finally: What is the SERVICE UUID for being able to connect LE device as RC2/RC3 into RaceChrono ? :)
according to: https://www.bluetooth.com/specifications/assigned-numbers/service-discovery/
both 0x1101 (serialport) and 0x0003 (rfcomm) does not show up my LE in the list to being able to connect.

my sample data:
$RC2,,1457,,,,2107,2,,,,,,,,*3E
$RC2,,1458,,,,2100,2,,,,,,,,*36
$RC2,,1459,,,,2100,2,,,,,,,,*37
$RC2,,1460,,,,2100,2,,,,,,,,*3D
$RC2,,1461,,,,2100,2,,,,,,,,*3C
$RC2,,1462,,,,2100,2,,,,,,,,*3F
$RC2,,1463,,,,2107,2,,,,,,,,*39
$RC2,,1464,,,,2100,3,,,,,,,,*38
$RC2,,1465,,,,2100,3,,,,,,,,*39
$RC2,,1466,,,,2100,3,,,,,,,,*3A
$RC2,,1467,,,,2107,3,,,,,,,,*3C
$RC2,,1468,,,,2107,3,,,,,,,,*33
$RC2,,1469,,,,2100,3,,,,,,,,*35

Comments

  • RaceChrono does not support streaming $RC2/RC3 data through Bluetooth LE. It is supported only through Bluetooth RFCOMM. I guess there's no big reason why it could not be supported, but there probably will be some problems with bandwidth. I will consider this.
  • Thanks. I can go with raw CANbus, but I have also few sensors that are out of CANbus in the car, so anyway, I'll be processing the CANbus data on Arduino, mix it with the rest and then send it via $RC2/3 to RaceChrono.

    In my opinion, the bandwidth of CAN will be still higher on BLE anyway. I'm aiming for 10Hz on serial $RC2/3 of BLE that should be still fine.

    Looking forward to have this feature on BLE in upcoming releases, if you will consider it is worth it ;-) I expect the UUID will be the same, but there will be one more option for the $RC2/3.

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