Java GUI和Arduino-从串行中提取信息

Question

I am currently working in an Arduino project. In which I need to read 5 analog sensors.

The arduino code for each sensor its really simple. But it is the following:

void setup() 
 {
  Serial.begin(9600);
 }

void loop() 
 {
 int sensor1 = analogRead(A0);
 float volt1 = sensor1 * (5.0 / 1023-0);
 Serial.print("The voltage on the sensor  1 is:   ");
 Serial.println(volt1);
 }

Using the Java documentation found on the Arduino Website http://playground.arduino.cc/Interfacing/Java I was able to set up the Rx and Tx libraries. And I was also able to get data from the serial port in the Java Console. What I need to do now is to extract that information from the console and display it on a GUI.

In the Java console I have:

The voltage on the sensor 1 is: X
The voltage on the sensor 2 is: Y The voltage on the sensor 3 is: Z
The voltage on the sensor 4 is: W
The voltage on the sensor 5 is: A

And I need to put the values of X, Y, Z, W and A each one on a different JTextField

Thanks for the help

Answer 1

Looking at your sample output data:

The voltage on the sensor 1 is: X
The voltage on the sensor 2 is: Y
The voltage on the sensor 3 is: Z
The voltage on the sensor 4 is: W
The voltage on the sensor 5 is: A

It sounds like you simply need to get the data after the : character and remove the whitespace around the value so you can parse it as an floating point value. This should be simple using the String class:

1. get the last ":" character using indexOf()
2. chop the last part of the string using substring()
3. clear whitespace using trim()

Here's a basic example:

String stringFromSerial = "The voltage on the sensor 1 is: X";
String valueString = stringFromSerial.substring(stringFromSerial.lastIndexOf(":")+1).trim(); 
System.out.println(valueString);

If it does what you want, you could encapsulate this in a function:

float extractFloat(String serialMessage){
  float result = Float.NaN;
  try{
    result = Float.parseFloat(serialMessage.substring(serialMessage.indexOf(":")+1).trim());
  }catch(Exception e){
    System.err.println("Oh-oh! Something went wrong trying to convert " + serialMessage);
    e.printStackTrace();
  }
  return result;
}

I'm not sure if it's worth sending so many characters though. You may want to consider sending the values separated by comma, as in a csv row.

Something along these lines:

Serial.print(volt1);
Serial.print(",");
Serial.print(volt2);
Serial.print(",");
Serial.print(volt3);
Serial.print(",");
Serial.print(volt4);
Serial.print(",");
Serial.println(volt4);

The nice thing about this is that in newer versions of Arduino( version 1.6.6 or above ) you should be able to use Tools > Serial Plotter .

Additionally, if you're not stuck to raw java and swing components, you might want to check out Processing and it's Serial library

Answer 2

I am not quite clear on specifics of your question, but I don't have enough points to comment, so I will answer at least part of it.

new JTextField(Float.toString(volt1));

Will create a JTextField with the value of the voltage. You can assign the created field to whatever variable you wish.

I am not sure why you would want to extract the value from the console when you have the value right there in a variable.

Does that help?

If not, could you be more specific in your requirements and why you want to get the value from the console?