### Author:  [@cola](https://discourse.processing.org/u/cola)
#### Post date: [February 8, 2025, 2:22pm UTC](https://discourse.processing.org/t/esp32-bluetooth-transmission-problem/45730/1 "2025-02-08T14:22:20Z")
Part of the Arduino function is as follows：
```auto
void sendDataThroughUART(void){
DataPacket[0] = ecgFilterout;
DataPacket[1] = ecgFilterout >> 8;
DataPacket[2] = resWaveBuff;
DataPacket[3] = resWaveBuff >> 8;
DataPacket[4] = globalRespirationRate;
DataPacket[5] = globalRespirationRate >> 8;
DataPacket[6] = globalHeartRate;
DataPacket[7] = globalHeartRate >> 8;
DataPacket[8] = 0;
//send packet header
for(int i=0; i<5; i++){
SerialBT.write(DataPacketHeader[i]);
}
//send 30003 data
for(int i=0; i> 8) ; // ignore the lower 8 bits out of 24bits
resWaveBuff = (int16_t)(ecgRespirationValues.sresultTempResp>>8) ;
SerialBT.printf("ECG: %d, Resp: %d\n", ecgWaveBuff, resWaveBuff); // 打印原始数据
if(ecgRespirationValues.leadoffDetected == false)
{
ECG_RESPIRATION_ALGORITHM.ECG_ProcessCurrSample(&ecgWaveBuff, &ecgFilterout); // filter out the line noise @40Hz cutoff 161 order
ECG_RESPIRATION_ALGORITHM.QRS_Algorithm_Interface(ecgFilterout,&globalHeartRate); // calculate
respFilterout = ECG_RESPIRATION_ALGORITHM.Resp_ProcessCurrSample(resWaveBuff);
ECG_RESPIRATION_ALGORITHM.RESP_Algorithm_Interface(respFilterout,&globalRespirationRate);
}else{
ecgFilterout = 0;
respFilterout = 0;
}
sendDataThroughUART();
}
}
}
```
In my serial port debugging, SerialBT.printf () displays normally, but in processing, no data is received. How can I debug this? I don’t know if it’s because of a problem with Bluetooth transmission or something else. I did not modify any transmission protocol, I just converted the serial port transmission to Bluetooth to see if it is feasible. Below is the serial port protocol connection.
> **[GitHub - Protocentral/protocentral\_openview: GUI for plotting/storing data from ProtoCentral...](https://github.com/Protocentral/protocentral_openview)**
>
> GUI for plotting/storing data from ProtoCentral breakouts
I hope someone can provide debugging suggestions, thank you very much! 🥲
---
### Author:  [@glv](https://discourse.processing.org/u/glv)
#### Post date: [February 8, 2025, 3:38pm UTC](https://discourse.processing.org/t/esp32-bluetooth-transmission-problem/45730/2 "2025-02-08T15:38:38Z")
Hello @cola,
> [@cola](#):
>
> In my serial port debugging, SerialBT.printf () displays normally, but in processing, no data is received.
Do you serial over Bluetooth set up correctly on your PC?
> **[Standard Serial over Bluetooth on Windows 10](https://community.element14.com/technologies/internet-of-things/b/blog/posts/standard-serial-over-bluetooth-on-windows-10)**
>
> I've recently been doing more work with BLE devices and communicating with them using my Windows PC. I've mainly been using WebBLE - most recently with the Nicla Sense ME.I've started using MIT App Inventor to create apps for my iOS and Android...
Try some simple code and just send a single character and try to receive that on Processing or any other _terminal emulator_ that connects to a serial port.
You must select correct COM port, BAUD rate, etc.
> **[List of terminal emulators](https://en.wikipedia.org/wiki/List_of_terminal_emulators)**
>
> This is a list of notable terminal emulators. Most used terminal emulators on Linux and Unix-like systems are GNOME Terminal on GNOME and GTK-based environments, Konsole on KDE, and xfce4-terminal on Xfce as well as xterm.
`:)`
---
### Author:  [@cola](https://discourse.processing.org/u/cola)
#### Post date: [February 9, 2025, 9:40am UTC](https://discourse.processing.org/t/esp32-bluetooth-transmission-problem/45730/3 "2025-02-09T09:40:39Z")
I used a simple example to test Bluetooth transmission, and everything worked fine. I think this may be related to the fact that serialBT.write() does not have its own delimiter when writing, because the data I see on the serial monitor is continuous.
The example to test Bluetooth transmission code:
```auto
#include "BluetoothSerial.h"
BluetoothSerial SerialBT;
// define deviceName
const char *deviceName = "ESP32_BT_Example";
// counter
int count = 0;
void setup() {
Serial.begin(115200);
// initial Bluetooth
if (!SerialBT.begin(deviceName)) {
Serial.println("Bluetooth initialization failed!");
while (1);
}
Serial.println("Bluetooth is activated, waiting for connection...");
Serial.print("deviceName：");
Serial.println(deviceName);
}
void loop() {
// waiting for connection
if (SerialBT.connected()) {
// send data
String message = "Hello World #" + String(count++);
SerialBT.println(message);
Serial.println("sendmessage：" + message);
senddata();
} else {
Serial.println("waiting for connection...");
}
delay(1000);
}
void senddata(){
const char DataPacketHeader[5] = {0x01, 0x02, 0x03, 0x04, 0x05};
for (int i = 0; i < 5; i++) {
SerialBT.write(DataPacketHeader[i]);
}
SerialBT.write(0x0A);
}
```
In addition, I also saw that the transmission packet on the Bluetooth transmission serial port complies with the transmission protocol.
This may be back to the previous transmission protocol problem.
---
### Author:  [@cola](https://discourse.processing.org/u/cola)
#### Post date: [February 9, 2025, 9:57am UTC](https://discourse.processing.org/t/esp32-bluetooth-transmission-problem/45730/4 "2025-02-09T09:57:31Z")
I can receive data but the waveform drawn is not ECG
🥲
And the data receiving speed is much slower than the serial port output.
---
### Author:  [@cola](https://discourse.processing.org/u/cola)
#### Post date: [February 9, 2025, 11:03am UTC](https://discourse.processing.org/t/esp32-bluetooth-transmission-problem/45730/6 "2025-02-09T11:03:04Z")
The redundant delay added during my Bluetooth transmission caused data transmission problems. Thanks for your answer, I solved my problem! 😳
---
### Author:  [@jafal](https://discourse.processing.org/u/jafal)
#### Post date: [February 9, 2025, 2:33pm UTC](https://discourse.processing.org/t/esp32-bluetooth-transmission-problem/45730/7 "2025-02-09T14:33:11Z")
> [@cola](#):
>
> I can receive data but the waveform drawn is not ECG
ECG/esp example
> **[ECG Monitoring system using AD8232 with Arduino or ESP32 IOT Based – Circuit...](https://www.circuitschools.com/ecg-monitoring-system-using-ad8232-with-arduino-or-esp32-iot-based/)**