CODEWITHSUNDEEP
c#arduinoserial-port
Amir Abbas
Amir Abbas

Reputation: 49

c# serial read doesn't do function on certain serial input

I have a program that reads serial data from an arduino through a com port. It works successfully when i program it to print the serial data onto a console, and it does so.

For example, the arduino says outputs "21", and the console writes "21".

But if I make an if statement saying If(data == "21"){/*dosomething*/} it doesnt work even if the data is printed as "21".

Here are the parts of my code related to this issue.

Arduino

if(digitalRead(i) == HIGH && stat[i-2] == false){
      Serial.print(i); Serial.println(1);
      stat[i-2] = true;
    }

The arduino code is kind of difficult to understand without the rest of the code, but all it does is scans all the ports to see if one of them is high. If it is, it prints the port number and a 1 next to it. For example if port 2 is high, it outputs "21". The same happens when port 2 is low, it outputs "20".

C# (an event handler)

private static void DataReceivedHandler(object sender, SerialDataReceivedEventArgs e)
        {
            SerialPort serialPort1 = sender as SerialPort;
            string dataString = (serialPort1).ReadLine();
            screen.clearline();
            Console.Write(dataString);

            if (dataString == "connectAlready")
            {
                connect.con();
            }
            if (dataString == "20")
            {
                Console.WriteLine("pdown");
            }
            if (dataString == "21")
            {
                Console.WriteLine("pup");
            }
        }

This is the event handler called when data is received. It prints data to the screen such as "21","20", but it does not perform the functions in the If statements.

Any help would be appreciated, thank you very much.

Upvotes: 0

Views: 404

Answers (1)

Malachi Willey
Malachi Willey

Reputation: 328

My guess is that the strings you are comparing aren't completely equal. Arduino's documentation for its println() function states that the serial print ends in a carriage return character ('\r'), followed by the newline character ('\n'). The SerialPort.ReadLine() function reads and returns the string "up to the NewLine value in the input buffer" (found here), so the '\r' character is probably still in dataString.

If this is your problem, you can solve it by removing the last character with something like: 

dataString = dataString.TrimEnd('\r');

Upvotes: 2

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