Keyestudio Smart Little Turtle Robot V3 Manual page 117

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Bluetooth
void setup() {
Serial.begin(9600);
}
void loop() {
if(Serial.available() > 0)
{
ble_val = Serial.read();
Serial.println(ble_val);
}
}
//***********************************************************************
(There will be contradiction between serial communication of code and
communication of Bluetooth when uploading code, therefore, don't link
with Bluetooth module before uploading code.)
After uploading code on development board, then insert Bluetooth
module, wait for the command from cellphone.
//make sure if there is data in serial buffer
//Read data from serial buffer
//Print
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