查看“Simulate voltage meter”的源代码

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==Objective==

The course will show you how to simulate a multimeter with Microduino. The reading of the “multimeter” will be displayed on Processing.

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

*Other Equipment
**A USB cable 
**A bread board
**A resistor of 1M Ω 
**A resistor of 100K Ω
**A box of jumpers 

==Schematic Diagram==

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

The schematic diagram adopts A2 pin. There are four channels totally, corresponding to the pins of A0, A1, A2, A3 respectively.  The voltage reading will be displayed in Channel One. 

==Program==

Referring to  AnalogVoltmeter

AnalogVoltmeterProcessing

==Debugging==

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


Step 2：Here is  the code we need:

The code of the two ends (Processing and Microduino)
Microduino:

//The voltage value will be received by Processing via serial port output 
  void loop()
  {
      // take a number of analog samples and add them up
      while (sample_count < NUM_SAMPLES) {
          // sample each channel A2 to A5
          for (l_cnt = 0; l_cnt < 4; l_cnt++) {
              sum[l_cnt] += analogRead(A2 + l_cnt);
          }
          sample_count++;
          delay(10);
      }
      // calculate the voltage for each channel
      for (l_cnt = 0; l_cnt < 4; l_cnt++) {
          voltage[l_cnt] = ((float)sum[l_cnt] / (float)NUM_SAMPLES * V_REF) / 1024.0;
      }
    
      // each voltage is multiplied by the resistor network
      // division factor to calculate the actual voltage
      voltage[0] = voltage[0] * DIV_1;
      voltage[1] = voltage[1] * DIV_2;
      voltage[2] = voltage[2] * DIV_3;
      voltage[3] = voltage[3] * DIV_4;
    
      // send voltages to Processing application via serial port / USB
      // voltage 1 - A (pin A2)
      Serial.print("A ");
      Serial.print(voltage[0], 1);
      Serial.print("V ");
      // voltage 2 - B (pin A3)
      Serial.print("B ");
      Serial.print(voltage[1], 1);
      Serial.print("V ");
      // voltge 3 - C (pin A4)
      Serial.print("C ");
      Serial.print(voltage[2], 1);
      Serial.print("V ");
      // voltage 4 - D (pin A5)
      Serial.print("D ");
      Serial.print(voltage[3], 1);
      Serial.print("V ");
      Serial.println("");
      delay(10);
      // reset count and sums
      sample_count = 0;
      for (l_cnt = 0; l_cnt < 4; l_cnt++) {
          sum[l_cnt] = 0;
      }
  }

Processing:

//After getting the data of the first serial port 
    println(Serial.list());
    // modify Serial.list()[0] to select correct serial port
　　 ser_port = new Serial(this, Serial.list()[0], 9600);


Function Description:

Serial Event: 
serialEvent(Serial p)

Displaying the channel and voltage:  
voltage (int channel, String volts)

Drawing graph axis: 
DrawGraphAxis(int pos_x, int pos_y, int width, int height)

Drawing graph: 
DrawGraph (String voltage, int channel, int pos_x, int pos_y, int scale)

Drawing scale and radio box:   
DrawScaleSelect (int x_pos, int y_pos, int scale)



Step 3：Uploading the code and compiling successfully. 

Step 4：Finding a battery or something similar and putting it between the red and the black lines, then watching the reading on the screen. Please refer to the image above.

==Result==

The voltage reading of the A5 pin will be displayed in Channel Four on the screen, just as follows: 
[[File:AnalogVoltmeterResult.jpg|600px|center|thumb]]


==Video==


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