I'm trying to send and receive encrypted words/phrases/data from one arduino to another through bluetooth module hc05.
The problem I am facing is the following code.
The objective is to enter the right key to decryp the data I'm receiving.
When I enter A , it works perfectly and asks me for the second letter but then when I enter B it gives me the error, it enters the else: (B) Caracter errado. Reinicie o serial monitor. and also does not "reset" the code.
I'm calling this void on the void loop (no need to show it since I don't have anything else there, unless you really want me to! Let me know).
I tried this code on tinkercad and it worked 100% with no errors. All the letters worked perfectly well and if I entered the wrong one it would reset so I could enter the A letter again.
Not sure what I'm missing here!
Thanks in advance.
void desencript() {
Serial.println("Insira a chave para desencriptar: ");
delay(10000);
char data = Serial.read();
if (data == 'A')
{
Serial.println("Correto. Insira o 2º caracter");
delay(10000);
char data1 = Serial.read();
if (data1 == 'B')
{
Serial.println("Correto. Insira o 3º caracter");
delay(20000);
char data2 = Serial.read();
if (data2 == 'C')
{
Serial.println("Chave aceite.");
delay(20000);
Serial.println("Desencriptação iniciada.");
delay(500);
do
{
digitalWrite(12, HIGH);
}
while (data2 == 'C');
}
else {
digitalWrite(12, LOW);
Serial.println("(C) Caracter errado. Reinicie o serial monitor.");
}
}
else {
digitalWrite(12, LOW);
Serial.println("(B) Caracter errado. Reinicie o serial monitor.");
}
}
else {
digitalWrite(12, LOW);
Serial.println("(A) Caracter errado. Reinicie o serial monitor.");
}
//Serial.flush();
}
OK, so you receive an 'A' and straight after that you read again; who guarantees that there is anything available at that moment?
if (data == 'A')
{
Serial.println("Correto. Insira o 2º caracter");
delay(10000);
char data1 = Serial.read();
An other problem is
do
{
digitalWrite(12, HIGH);
}
while (data2 == 'C');
data2 will never change so you will get stuck in that while-loop
A very rough way to solve the first problem, not recommended.
if (data == 'A')
{
Serial.println("Correto. Insira o 2º caracter");
delay(10000);
while(Serial.available() == 0)
{
}
char data1 = Serial.read();
And the better way is to use a finite state machine / sequencer. You start with a state where you inform the user. Next you go to the next state/step and process the received character. This repeats. If there is an error, the variable state is set to 0 so the process starts from the beginning. In the last step, we simply ignore what is received and go back to the beginning.
void desencript()
{
// variable to remember the state/step
static byte state = 0;
// get serial data
int serialData = Serial.read();
// if nothing received
if (serialData == -1)
{
// nothing to do
return;
}
switch (state)
{
// tell user to start
case 0:
Serial.println("Insira a chave para desencriptar: ");
// go to next state / step
state++;
break;
// process first character
case 1:
if (serialData == 'A')
{
Serial.println("Correto. Insira o 2º caracter");
// next state / step
state++;
}
else
{
digitalWrite(12, LOW);
Serial.println("(A) Caracter errado. Reinicie o serial monitor.");
// back to the beginning
state = 0;
}
break;
// process second character
case 2:
if (serialData == 'B')
{
Serial.println("Correto. Insira o 3º caracter");
state++;
}
else
{
digitalWrite(12, LOW);
Serial.println("(B) Caracter errado. Reinicie o serial monitor.");
state = 0;
}
break;
// process third character
case 3:
if (serialData == 'C')
{
Serial.println("Chave aceite.");
Serial.println("Desencriptação iniciada.");
state++;
digitalWrite(12, HIGH);
}
else
{
digitalWrite(12, LOW);
Serial.println("(C) Caracter errado. Reinicie o serial monitor.");
state = 0;
}
break;
// process any character to stop and go to the beginning
case 4:
// if any new data is received in this state, we will go back to the beginning
state = 0;
break;
}
}
For other various example sketches for reading text from Serial take a look at my Arduino Software Solutions tutorial.
Has examples for single char reads as well as Strings both blocking and non-blocking examples.
