Nevermind, I just fixed it.

Now the interrupt looks like this:

if (interruptCounter > 0) {
if (flag_data){
portENTER_CRITICAL(&timerMux);
interruptCounter--;
portEXIT_CRITICAL(&timerMux);
totalInterruptCounter++;

if (flag_samples<500){
dato[flag_samples] = analogRead(34);
flag_samples ...

You should check mit app inventor. There are a lot of examples on how to build an app that sends and receives data via BLE o classic Bluetooth.

For example: https://community.appinventor.mit.edu/t ... ide/1980/3

Hey there!
I'm having some troubles using more than one timer with my ESP32. The second interrupt works well, but I seem to be accessing the first one only one time. It must be some variable I'm forgetting to update, but I just can't get it to work.

It seems as if interruptCounter isn't increasing ...