Arduino program. The serial monitor keeps rolling and always \"invalid input\".
ID: 3572350 • Letter: A
Question
Arduino program. The serial monitor keeps rolling and always "invalid input". Can't figure out why. Help.
String username;
void setup()
{
Serial.begin(9600);
//Green LED on D3
//Red LED on D4
pinMode(3,OUTPUT);
pinMode(4,OUTPUT);
digitalWrite(3,0);
digitalWrite(4,0);
}
void loop()
{
test_username();
}
//Character array to store data recorded from serial monitor char
charBuf[5];
//Recursive function to keep prompting till right username is displayed
void test_username()
{
Serial.print("Please enter your username or ID:");
delay(2000);
if(Serial.available()>0)
{
username=Serial.readString();
username.toCharArray(charBuf, 5);
}
if(strcmp(charBuf,"Tony")==0)
{
Serial.println("Hello Student");
//Display access granted and toggle LED
digitalWrite(3,1);
digitalWrite(4,0);
delay(500);
}
else
{
Serial.println("Invalid username");
digitalWrite(3,0);
digitalWrite(4,1);
delay(500);
test_username();
}
}
Explanation / Answer
This is because
if(strcmp(charBuf,"Tony")==0) => the entered name wil be compared with Tony. hence if you give Tony as input, the program will display welconme message and stop running.