Hello I have this code I am trying to run alongside a python script and it sort of does what I want it to do but anything inside of the if data = 'x' statement will not run and the beeps continue as soon as the value is no longer being printed to the serial.
const int buzzerOne = 9;
const int buzzerTwo = 10;
bool inChair = false;
bool personFound = false;
int buzzTone1 = 1500;
int buzzTone2 = 3000;
void setup() {
Serial.begin(9600);
pinMode(buzzerOne, OUTPUT);
pinMode(buzzerTwo, OUTPUT);
}
void loop() {
while (personFound == false) {
int val;
val = analogRead(0);
if (Serial.available() > 0) {
String data = Serial.readString();
if (data == 'x') {
val = 0;
personFound = true;
}
}
if (val >= 1) {
tone(buzzerOne, buzzTone1);
delay(500);
noTone(buzzerOne);
tone(buzzerTwo, buzzTone2);
delay(500);
noTone(buzzerTwo);
}
}
}
Could you please help me figure out why this if statement isn't running at all?
I'm not an expert on the serial port but my guess is you are reading more than one byte from the serial port. Without knowing the source of the "x" I cannot comment on what might be at the serial port.
If you made:
if (Serial.available() > 0)
to
if (Serial.available() = 1)
You would read a byte as soon as the program got around to the serial part of the code.
Do you know what else might be coming in on the serial port? i.e. can you strip all but the 1st character?
C++ doesn't like strings, you should change "String" to an array of char. A quick google of "array of char" will give you much more info.
There is only one character coming through so it would probably be smarter to change to an array of char anyway. I will try your fix and see if it helps, thank you!
The String class has no problem although many are convinced to the contrary.
It is your sketch that contains several errors:
you are comparing a pointer to char with a char variable type: you should use double quotes and not single quotes.
BUT, the string is received from the serial line, so in addition to the character 'x' there will also be line terminators '\n' and '\r' (based on how you configured the terminal software).
the variable val will be different from 0 only in the case in which the potentiometer is completely closed (and it may not be so even in that case if the cursor is not precise) because you are reading again A0 just after some micorseconds.
Therefore the two buzzers will always be in operation by introducing a total delay of 1000 milliseconds which affects on receiving data in a heavy way. You should use a non-blocking approach (millis ()) for handling buzzers.
If don't work on your real hardware is because, as I stated, it depends of which type of line endings you selected. This is the reason why this way is not the best.
Please stop writing random lines of code and focus on what you are doing.
Once you understand the concept, everything will be easier: when you send some text from a serial connection (terminal or python script, is the same), one or two additional characters will be added as line ending.
Serial.available() return the numbers of total bytes you can read from the serial buffer.
When you add the buzzers piece of code, you will never be able to process the single byte because the delay introduced! Indeed in the mean time, the \r and the \n characters will be fitted in buffer, so Serial.available() will be != 1
This is char it can NEVER equate to String not in a million years. It is like saying I have a box of apples, why when I pick up one apple and compare it to oranges
