查看“Resistance meter”的源代码

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==Objective==

The course will show you how to use Processing to display the graph of the ohmmeter value, and the ohmmeter will be achieved by microduino. 

==Equipment==
*'''[[Microduino-Core]]'''
*'''[[Microduino-FT232R]]'''

*Other Hardware Equipment 
**A USB cable 
**A 20k Ω resistor 
**A 104 ceramic capacitor 
**A bread board 
**A box of jumpers 



==Schematic Diagram==


[[File:ResistanceMeterSchematics.jpg|600px|center|thumb]]


==Program==

Referring to  ResistanceMeter

processingResistanceMeter

==Debugging==

Step 1：Building hardware environment according to the schematic diagram, just as follows: 
[[File:IResistanceMeterConnectionDiagram.jpg|600px|center|thumb]]


Step 2：Here is the code we need：

The code of two ends (Processing and Microduino) 

Microduino:

//Using filter algorithm to calculate resistance and displaying the data on Processing via serial output.   

  //filter Algorithm
  float filter()
  {
    float sum = 0;
    for(int count = 0; count < N; count++)
    {
      sum += r;
      delay(5);
    }
    return (float)(sum / N);
  }

Processing:

//After getting the data of the first serial port, you can define or cache the data if there is a new line. 

 // is always my Microduino, so I open Serial.list()[0].
 // Open whatever port is the one you're using.
 myPort = new Serial(this, Serial.list()[0], 9600);
 myPort.bufferUntil('\n'); // Trigger a SerialEvent on new line

//On the screeen, displaying the data received from Microduino in the form of graph and marking scale. 

  String val = myPort.readStringUntil('\n');
  if (val != null) {
    if ("Infinity!!".equals(val)) {
      unit="resistancetoo big";
    } 
    else {
      if ("K ohm".equals(val)) {
        unit="K ohm";
      }
      else if (" ohm".equals(val)) {
        unit=" ohm";
      }
      else {
        val = trim(val);
        println(val);
        resistance=Float.parseFloat(val);
      }
    }
  }
  vals[vals.length-1] = 200-resistance;
  //Display scale
  text ( "200-", 370, 10); 
  text ( "--", 370, 50); 
  text ( "100-", 370, 100);
  text ( "--", 370, 150); 
  text ( "0-", 370, 200); 
  //show current num
  text ( resistance+unit, 0, 10);

Step 3：Uploading the code and compiling it successfully. 

Step 4： Putting the resistor ready to measure between the yellow and the black lines on the graph, watching resistance on Processing. 

==Result==

The graph will display the current resistance.    
[[File:IResistanceMeterResult.jpg|600px|center|thumb]]


==Video==