Nobuteru Asai

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6

Components

	ARDUINO_NANO null	x 1
	74HCU04D Toshiba	x 1
	DTC143ZMT2L ROHM(罗姆)	x 1
	7805	x 1
	TQ2-5V ATQ209 Panasonic	x 1

Tools, APP Software Used etc.

arduino IDE

Arduino

Description

LC meter of using the franclin oscillator アルディーノマイコンを使ったLCメーター

This LC meter is majorly composed by 74HCU04 Franclin oscillator and Arduino frequency counter.

The east German engineer of Dr.Hegewald had published this LC meter design principal. AADE and some suppliers introduced the products for HAMs. At the original design they used PIC. (Such information is kept on VK3BHR web site"https://sites.google.com/site/vk3bhr/home/lcm1/faq?pli=1")

I followed this method by using Arduino to recognize the principal of L or C measuring.

I had posted my sketch on GITHUB("https://github.com/Nobcha/ArduinoLCM"). I also explained how to get the value by measuring frequency of LC circuit.

As the calculated value is based on the difference of the frequency, the parasitical component along the real oscillating circuit shall be avoided. And the gotten value is referenced on the precise sample. Also measuring frequency is nearly the practical usage. This meter can be worked precisely nevertheless the simple structure. Please refer my WEB for assembling.("http://chitose6thplant.web.fc2.com/LCM/Arduino_LCM_EXP.htm")

My sketch is merely simple and please modify for your preference.

Thanks for reading.

nobcha

74HCU04でフランクリン発振器を構成し、Arduino nanoで制御計算するLCメータです。ガーバーファイルや、スケッチなどはGITHUB("https://github.com/Nobcha/ArduinoLCM")にアップロードしてあります。詳しくはブログ("http://chitose6thplant.web.fc2.com/LCM/Arduino_LCM_EXP.htm")も参照ください。操作例は次のYOUTUBEにあります。

Please visit YOUTUBE to see how to use it. https://youtu.be/LxzoExQPcYk:embed:cite

Code

LC meter by Arduino

Arduino

// updated 2021.11.20 
// Arduino LC meter V2.1 
//
// 2021.11.18 Franclin OSC timing
// 2021.11.15 i2cLCD_PCF8574_0x27
// 2021.10.10 Adopted dtostrf for xxx.xxxuH, decrease delay value
// 2021.09.17 Displaying with standard function Gate time 200ms
// LC meter Arduino  2020.07.09, 20200716 f1 ok, 20200717 f2 ok
// 20200718 xxxxxxxpF xxxxxuH OK  
// 20200718  if (test_value<1.000E+2)  xxxxxnH OK
// 2020.06.25 Frequency counter ; Many thanks for below sketch.
// Sample sketch（FreqCount_2017-0207-001-ok）
// "http://interface.khm.de/index.php/lab/interfaces-advanced/arduino-frequency-counter-library/"
//   Using Counter1 for counting Frequency on T1 / PD5 / digitalPin 5 
//   Using Timer2 for Gatetime generation
//   D5:FRQ input, D6:Driving the relay, D7：L/C select PINMODE setting
// Replace calling name for i2cLCD

// Based on PIC1827_main_c 
/*************************************************
 LC  METER  by PIC 
1602  display  by  4  bit  with  PIC16F1827 
By  nobcha  all  right  reserved
Ver  1.0  09/29/2010  for  PIC16F88 
Ver  2.0                for  PIC16F428
Ver  3.0  02/10/2012  for  PIC16F1827
Hitech  C  &  MPLAB  PIC16F1827  +  LCD 
MPLAB  IDE  V8.73a  HiTECH  C  V9.83
**************************************************/

#include <FreqCounter.h>
#include <Wire.h>
// AKIDUKI LCD[AQM0802A][AQM1602A] ST7032i
// http://zattouka.net/GarageHouse/micon//Arduino/LCD/I2CLCD.htm
#include <skI2CLCDlib.h> // For 0x3E AKIDUKI LCD

// i2c lcd instance
//  Thanks for giving information about i2c LCD adapter
//  https://github.com/marcoschwartz/LiquidCrystal_I2C
#include <LiquidCrystal_I2C.h>

int PIN_Led = 13;        // Gate timing LED lit port
boolean LED_Stat = 1;    // Gate ON/OFF timing LED
int SEL_SW = 7;          // L/C select SW
boolean SEL_SW_Stat = 1; 
int CAL_ON = 6;          // Caliblation relay
int ON = 1;
int OFF = 0;
// ST7032 lcd instance
  skI2CLCDlib LCD(0x3E, 16);  // ＬＣＤ i2c address, display column 16 characters
// initialize Serial, i2cLCD,  PCF8574
  LiquidCrystal_I2C lcdi2c(0x27,16,2);     // Adress*0x27, 16 columns, 2 lines



volatile unsigned long freq_d;
volatile unsigned long freq;
volatile boolean err;
char charbuf[16];                     // Character array for sprintf function
volatile unsigned char i, l_power,  l_digi,  l_unit,  c_power,  c_digi, c_unit;
volatile unsigned long  freq1, freq2, freq3; 
volatile float  c_int, l_int, l_inv, f_sq;
volatile float  c_cal=1.000e+3;
volatile float  test_value;


volatile unsigned long freq_count()
{
  FreqCounter::f_comp = 8;            // Set compensation to 12
  FreqCounter::start(200);            // Start counting with gatetime of 200ms
  while (FreqCounter::f_ready == 0);  // wait until counter ready
  freq_d = FreqCounter::f_freq;       // read result
  Serial.println(freq_d);             //  20210917 print freq_d@200ms
  if(freq_d<2000) err=1;              //  ?? too low, less than 10kHz
  return freq_d;                      // 
}


float freq_cal(unsigned long f1, unsigned long f2){
                                      //  Coefficient calculating
  return((float)(f1)/(float)(f2)*(float)(f1)/(float)(f2)-1);
}

void LCDSetCursor( int column, int line )
{
  LCD.SetCursor( column, line );
  lcdi2c.setCursor( column, line ) ;  
} 

void LCDPuts( char *const s )
{
  LCD.Puts( s ) ;  
  lcdi2c.print( s ) ; 
}

void setup() {
  Serial.begin(9600);         // connect to the serial port
  Serial.println("LCM on i2cLCD v2.0"); // Version 2.0
  pinMode(PIN_Led, OUTPUT);
  pinMode(SEL_SW, INPUT);
  pinMode(CAL_ON, OUTPUT);
  

  
// Initializing LCD mojule
// ICON OFF,contrast setting(0-63),VDD=5V
  LCD.Init(LCD_NOT_ICON,32,LCD_VDD5V) ; //Change to 5V on 20200612 
  
// PCF8574 LCD
// Iniatilize i2c LCD
  lcdi2c.init(); 
  lcdi2c.backlight();
   
  delay(100);

// Write
  LCDSetCursor(0,0) ;                // Starting point [00H]
  LCDPuts("LCM METER      ") ;       // [00H]
  Serial.println( "TEST2" );  
  delay(20);    
  LCDSetCursor(0,1) ;                // 2nd line [40H]
  LCDPuts("  i2cLCD v2.0  ") ;       // [40H]

  delay(20);

}

void  loop() 
{
//  START  SWITCH  CHECK
//  If  caliblration
  Serial.println("WAIT SEL SW ON");
  while( digitalRead(SEL_SW) == 0 ){ } //  CAL  switch  check
  delay(20);
  while( digitalRead(SEL_SW) == 0 ){ } //  Check  again
  delay(200);
  /*  Get  frequency  1  and  display */
  Serial.println("SEL SW ON");
  freq1=freq_count();             //  F1  get  
  freq1=5*freq_count();           //  F1 get again as freq_count()
//                                result is based on 200ms gate 
  Serial.println("F1 gotten");
  Serial.println(freq1);
  LCDSetCursor(3,0) ;            // Display position set on 4th column
  LCDPuts(" f1=");    
  sprintf( charbuf,"%ld", freq1, 7);
  LCDPuts(charbuf);
  LCDPuts("Hz   ");  //
// Relay on f2 getting
  digitalWrite( CAL_ON, ON);      //  Calibration  capasitor  on
  delay(200);                     //  Wait  100ms
  freq2=freq_count();             //  Get  F2 
  freq2=5*freq_count();           //  Get  F2 
  digitalWrite( CAL_ON, OFF);     //  Calibration  capasitor off
    Serial.println("F2 gotten");
    Serial.println(freq2);
 /*  F2  displaying */
    LCDSetCursor(0,1);            // Move cursur to the top of 2nd line
    LCDPuts("f2=");    
    sprintf( charbuf,"%ld", freq2, 7);
    LCDPuts(charbuf);
    LCDPuts("Hz    ");            //
    delay(50);
/*  Calculating  C  and  L  */
  c_int=(float)(c_cal)/freq_cal(freq1,freq2);
                                   // Calcurate c_int from F and F2 pF
  f_sq=(float)(freq1)*(float)(freq1)/+1.000E+2;
                                   // (F1*F1)
    Serial.println("freq_cal= ");
    Serial.println(freq_cal(freq1,freq2));
  l_inv=(+3.9438E+1)*f_sq*c_int;   // 
  l_int=(+1.000E+16)/l_inv;        // uH
/*  for  debugging  */
      Serial.println("C/L unit gotten");
      Serial.println("C=");
      Serial.println(c_int);
      Serial.println("L=");
      Serial.println(l_int);
      LCDSetCursor(0,1);           // Move cursur to the top of 2nd line
      LCDPuts("C=");    
      sprintf( charbuf,"%d", (int)c_int);
      LCDPuts(charbuf);
      LCDPuts("pF ");              //
      LCDPuts("L=");  
      sprintf( charbuf,"%d", (int)l_int);
      LCDPuts(charbuf);
      LCDPuts("uH   ");            //
// Calibration finished
      Serial.println("Calibration end ");
      LCDSetCursor(3,0) ;          // Move cursur to the 4th of 1st line
      LCDPuts(" Calibrated   ");      
      delay(1000);
// Measurement starting check
    while( digitalRead(SEL_SW) == 1 ){  }  //  Wait sw status changed
  while (1)        // Testing forever
  {    
    digitalWrite(PIN_Led, LED_Stat=!LED_Stat);   //  LED  on/off 
    delay(100);
    LCDSetCursor(4,0);         //  Move cursur to the 8th of 1st line
    LCDPuts("SET TEST    ");   //  Ask setting L or C
    delay(300);
    freq3=freq_count();         //  Get  F3
    freq3=5*freq_count();         //  Get  F3
    Serial.println("F3 gotten");
    Serial.println(freq3);
    LCDSetCursor(3,0);         //  Move  cursur  to  the  top  of 2nd  line
    LCDPuts(" f3=");    
    sprintf( charbuf,"%ld", freq3, 7);
    LCDPuts(charbuf);
    LCDPuts("Hz");             //
    delay(100);
  /*  displaying  value */
    LCDSetCursor(0,1);         //  Move  cursur  to  the  top  of 2nd  line
/*  Metric  unit  changing  further study */
/* uH/mH  l_power=1; mH,   l_power=1000; uH, 
   pF/uF  c_power=1; pF,   c_power=1000; nF,  
 */
      l_power=1;
      l_digi=1;
      l_unit='u';
      c_power=1;
      c_digi=0;
      c_unit='p';  
/*  Calculating value whether C position or L */
    if(digitalRead(SEL_SW) == 0)            // If SW==0, start L measuring 
    {                                       // L position
      if ( freq3> 1000 ){
        test_value= ((freq_cal(freq1,freq3))*l_int);
        int f_rate =  (freq_cal(freq1,freq3)*1000);
        Serial.println("f_rate");
        Serial.println(f_rate);
        LCDPuts("L=");
        dtostrf( test_value, 7, 3, charbuf);    // Changed to use dtostrf(**)
        LCDPuts(charbuf);
        LCDPuts("uH          ");     
      /*
      sprintf( charbuf, "%d", (long) test_value );
      LCD.Puts(charbuf);
      LCD.Puts("uH          ");
      if (test_value<1.000E+2)
      {
        LCD.SetCursor(0,1);         //  Move cursur to the top of 2nd line       
        LCD.Puts("L=");
        sprintf( charbuf, "%d", (long) (test_value*1.0E+3 ));
        LCD.Puts(charbuf);
        LCD.Puts("nH         ");   
      }
      */
        Serial.println("L=");
        Serial.println( test_value);
        Serial.println("uH");  
      }
      else {
        LCDPuts(" No inducter    ") ;
        Serial.println( " No inducter    ");          
      }
    }
    else
    {
      test_value=((freq_cal(freq1,freq3))*c_int/c_power);
      Serial.println("C=");
      Serial.println( test_value);
      Serial.println("pF");
      LCDPuts("C=");
      sprintf( charbuf, "%u", (long) (test_value ));
      LCDPuts(charbuf);
      LCDPuts("pF           "); 
    }
    delay (500);
  }
}

Schematic and Layout

LC meter circuit diagram

LCM_CIRC.png

CAD-Custom parts and enclosures

Assembled

LCM_shot.jpg

Download BOM(Bill of materials)

Nov 14,2022

1,873 views

LC meter of using the franclin oscillator アルディーノマイコンを使ったLCメーター

The franclin oscillator is based on LC resonator. The frequency meter by Arduiono leads the value for unknown L or C. 小さなインダクタンスも測れ、精度も良好

1873

Published: Nov 14,2022

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