Payload used as string, thus "prints" adds garbage

[Franck78]

Board

ESP32-S3

Device Description

homemade

Hardware Configuration

homemade

Version

latest master (checkout manually)

IDE Name

ARduino IDE

Operating System

linux

Flash frequency

40

PSRAM enabled

no

Upload speed

115200

Description

Hello
v2.0.6

this is the output of the demo program using BLE_client

https://github.com/espressif/arduino-esp32/blob/master/libraries/BLE/examples/BLE_client/BLE_client.ino

We are now connected to the BLE Server.
Notify callback for characteristic 0000ffe1-0000-1000-8000-00805f9b34fb of data length 2
data: AT⸮⸮⸮?�⸮$

The data length is correct, I recognize just an 'AT' command from the HC06.
Line 32 of the demo program uses the payload directly as a string (serial.print) .

Maybe just add a warning for readers: this is a payload interpreted wrongly as a string for simplicity of the demo.

arduino-esp32/libraries/BLE/examples/BLE_client/BLE_client.ino

Line 32 in b63f947

Serial.println((char*)pData);

Sketch

bool isNotify) {
    Serial.print("Notify callback for characteristic ");
    Serial.print(pBLERemoteCharacteristic->getUUID().toString().c_str());
    Serial.print(" of data length ");
    Serial.println(length);
    Serial.print("data: ");
    Serial.println((char*)pData);

Debug Message

x

Other Steps to Reproduce

No response

I have checked existing issues, online documentation and the Troubleshooting Guide

• I confirm I have checked existing issues, online documentation and Troubleshooting guide.

[SuGlider]

Are you sure that HC-06 can be used as BLE?!
As far as I know HC-06 is Bluetooth v2.0 (classic) only.
Therefore it can't be used as BLE device.

[SuGlider]

The S3 can only connect using BLE with another BLE device.
You may consider using another ESP32/C3/S3 to connect, or maybe, a BLE module such as the HM-10, instead of HC-06.

[Franck78]

well, I swear to you I'm using my HC06 with the app you pointed me (ble client ino)

May be the bug is line 32 if we say that the 'bluetooth' transports an array of byte and a size for that array.

What I call HC-06 is the small thing from aliexpress .
https://www.aliexpress.com/item/1005002168517770.html
chip is CSR BC417143 (https://www.aliexpress.com/item/32323413263.html)

apparently, original one was bt2.0
https://www.digikey.com/en/products/detail/BC417143B-IRN-E4/BC417143B-IRN-E4DKR-ND/2001050
and probably upgraded with 'core 4.0' as seen on some other datasheet

[SuGlider]

Considering that your HC06 works with BLE, I can tell you that BLE doesn't understand NULL terminated strings.

The sender will send a payload with a defined length.
The receiver side will read the length and then get the payload.

If you want to Serial.print(char *) the payload, you shall add the '\0' at pData[length].

[Franck78]

If you want to Serial.print(char *) the payload, you shall add the '\0' at pData[length].

it happens it is your app in need of this zero ;)

[SuGlider]

I'll add that to the example. Thanks.