BLE_bluetooth Can't recieve data from arduino (esp32)

Questions about Thunkable
1

Hi,

I’m trying to recieve some response from arduino to thunkable. When I try to send to arduino ther’s no problem, recieving seems not to fire any erros but no response is shown.

image

I have arduino code:

/*
    Based on Neil Kolban example for IDF: https://github.com/nkolban/esp32-snippets/blob/master/cpp_utils/tests/BLE%20Tests/SampleWrite.cpp
    Ported to Arduino ESP32 by Evandro Copercini
*/

#include <BLEDevice.h>
#include <BLEUtils.h>
#include <BLEServer.h>
const byte ledG = 33;

// See the following for generating UUIDs:
// https://www.uuidgenerator.net/

#define SERVICE_UUID        "4fafc201-1fb5-459e-8fcc-c5c9c331914b"
#define CHARACTERISTIC_UUID "beb5483e-36e1-4688-b7f5-ea07361b26a8"


class MyCallbacks: public BLECharacteristicCallbacks {
    void onWrite(BLECharacteristic *pCharacteristic) {
      std::string value = pCharacteristic->getValue();

      if (value == "0") {
        digitalWrite(ledG, HIGH);
      } else {
        digitalWrite(ledG, LOW);
      }
    }

   void onRead(BLECharacteristic *pCharacteristic) {
      int MyResponse;
      
      if (digitalRead(ledG) == LOW){
        MyResponse = 1;
      } else { 
        MyResponse = 0;
      }

      pCharacteristic->setValue(MyResponse);
    }

    /*void onRead(BLECharacteristic *pCharacteristic) {
      struct timeval tv;
      gettimeofday(&tv, nullptr);
      std::ostringstream os;
      os << "Time: " << tv.tv_sec;
      pCharacteristic->setValue(os.str());
    }*/
};

void setup() {
  Serial.begin(115200);

  Serial.println("1- Download and install an BLE scanner app in your phone");
  Serial.println("2- Scan for BLE devices in the app");
  Serial.println("3- Connect to MyESP32");
  Serial.println("4- Go to CUSTOM CHARACTERISTIC in CUSTOM SERVICE and write something");
  Serial.println("5- See the magic =)");

  pinMode(ledG, OUTPUT);

  BLEDevice::init("MyESP32");
  BLEServer *pServer = BLEDevice::createServer();

  BLEService *pService = pServer->createService(SERVICE_UUID);

  BLECharacteristic *pCharacteristic = pService->createCharacteristic(
                                         CHARACTERISTIC_UUID,
                                         BLECharacteristic::PROPERTY_READ |
                                         BLECharacteristic::PROPERTY_WRITE
                                       );

  pCharacteristic->setCallbacks(new MyCallbacks());

  pCharacteristic->setValue("Hello World");
  pService->start();

  BLEAdvertising *pAdvertising = pServer->getAdvertising();
  pAdvertising->start();
}

void loop() {
  // put your main code here, to run repeatedly:
  delay(2000);
}
2

Hi @proximilius, hope you are having a great weekend. Our engineers made an update to our platform last night that should have resolved this. Can you please test this again?

3

Many thanks, now it works.

Maybe the problem was also my “onRead” function inside the arduino script. With the old script my information label on the app refreshed into a blank with no text. After a small change now everything seems to be working.

New arduino snippet (with un changed thunkable blocks):

void onRead(BLECharacteristic *pCharacteristic) {
      int MyResponse;
      
      if (digitalRead(ledG) == LOW){
        pCharacteristic->setValue("1");
      } else { 
        pCharacteristic->setValue("0");
      }
   }
4

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