How to Switch between Wifi and BLE on a Arduino nano IoT?

Question

I have got both BLE working to configure and setup the nano IoT, and WIFI working to send sensor data to a cloud DB.

I've found on Arduino Forum a possible solution it it https://forum.arduino.cc/t/coexistence-of-wifi-and-ble-in-arduino-nano-33-iot/676169

However I has a memory leak problem: every time I switch back to BLE it consumes roughly 500bytes of memory. This means all memory is exhausted within one hour or so and the Nano IoT crashes

Has anyone merged the two ideas. Have the Nano 33 IoT connected with both Wifi and BLE?

I know BLE and Wifi can't work in parallel on this board but can you easily and quickly switch between the two ?.

Miguel Silva Miguel Silva · Accepted Answer · 2021-09-01T08:38:35

In the meantime I've found an answer to the memory leak problem on the ArduinoBLE library:

It looks like the issue comes from the following file:

.\libraries\ArduinoBLE\src\utility\GATT.cpp

In void GATTClass::begin() a some objects are created with new. However they are not deleted in void GATTClass::end().

So the method need to be updated as follows:

void GATTClass::end()
{
  delete( _genericAccessService );
  delete( _deviceNameCharacteristic );
  delete( _appearanceCharacteristic );
  delete( _genericAttributeService );
  delete( _servicesChangedCharacteristic );
 _attributes.clear();
}

There's an open issue on GitHub https://github.com/arduino-libraries/ArduinoBLE/issues/192

Now back to the part of switch between BLE and WiFI. This is how to do it:

//Start Wifi
  wiFiDrv.wifiDriverDeinit();
  wiFiDrv.wifiDriverInit();
  status = WiFi.begin(ssid, pass);
  server.begin();

//...

// End Wifi    

  WiFi.end()     

//...

//Start BLE
    BLE.begin();
    BLE.scan(); 

//...

// End BLE
   BLE.stopAdvertise();   //don't think this is needed as I am reading other BLE devices
   BLE.stopScan();
   BLE.end();

BLEservice and BLEcharacteristics are done on the setup() part of the code.

How to Switch between Wifi and BLE on a Arduino nano IoT?

1 Answers