Increment a button in an android application using bluetooth

Hello!, Iam currently making a self balancing robot but I have a hard time tuning the PID, so I wanted to control the PID using the bluetooth module. pls help me code, I wanted to have an increment values to PID whenever I push a button in the android application. Thank you very much

What have you tried? This is NOT the place to ask about Android programming, so you must already have an Android app that can send data to the bluetooth device connected to the Arduino.

Only you have any idea what that application sends, so only you can write the code to read, and use, that data.

yes yes I have the data but Im still confused on coding…
this is what I have write…

if (Serial.available() > 0) {serialA =;Serial.println(serialA);}
state= digitalRead (F);
switch (serialA) {
case ‘F’:
Serial.println (Speed);


but it doesnt do the increment by 1, I need to hold the button first before it counts onto the next number.

but it doesnt do the increment by 1

Gee I can't imagine why. Unless, just possibly, 0.1 is not the same as 1.

Take your snippets to